Human Health and Disease - Class 12 Biology - Chapter 7 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Human Health and Disease | NCERT | Biology | Class 12
Consider the following statements:
Measles is caused by a virus in the paramyxovirus family, and it is normally passed through direct contact and through the air.
The virus infects the respiratory tract, then spreads throughout the body.
Which of the above statements is/are correct?
A) 1 Only B) 2 Only C) Both 1 and 2 D) Neither 1 nor 2
The correct answer is C) Both 1 and 2
Explanation:
Statement 1 explains that measles is caused by a virus belonging to the paramyxovirus family, which is transmitted through direct contact and airborne particles. This is accurate based on our understanding of the transmission and causative agent of measles.
Statement 2 notes that the measles virus first infects the respiratory tract and subsequently spreads throughout the body. This aligns with the pathophysiology of measles where initial respiratory infection leads to systemic spread.
Hence, both statements are correct.
Which of the following statements are not true about the sarcomere? I. The portion between consecutive Z-lines is the sarcomere. II. I band is also called the dark band. III. The Z-line bisects I-band. IV. The A-band is held together by the M-line.
A. I and II
B. I, III, IV
C. II and III
D. Only II
The correct option is D. Only II
The sarcomere is the functional unit of the muscle responsible for contraction and relaxation. It is defined as the segment between two successive Z-lines. Statement I is therefore true as it accurately describes the sarcomere.
The I-band is known as the light band or the isotropic band due to its appearance under a microscope. Consequently, Statement II is false because it incorrectly identifies the I-band as the dark band, which in reality is the A-band (also known as the anisotropic band).
Furthermore, the Z-line bisects the I-band, making Statement III true.
Lastly, Statement IV is accurate as well, since the A-band contains both actin and myosin filaments (thin and thick filaments, respectively), and it is indeed held together by the M-line.
Therefore, the only false statement among these is Statement II, making option D the correct answer.
Chronic use of drugs and alcohol may damage the liver, a condition known as:
A withdrawal
B addiction
C clotting
D cirrhosis
The correct answer is Option D: cirrhosis.
Cirrhosis is a medical condition that results from the chronic use of drugs and alcohol. This condition is characterized by the replacement of healthy liver tissue with non-functional scar tissue. Cirrhosis is typically associated with chronic alcoholism and other liver diseases, highlighting the detrimental impact of substance abuse on liver function.
The epithelial lining of the inner wall of the trachea bears cilia. What may be the purpose of this?
A Cilia help in pushing the air downwards.
B Cilia help in cleaning the air.
C Cilia beat upwards to push mucus out.
D Cilia are non-functional in the trachea.
The correct answer is Option B: Cilia help in cleaning the air.
Cilia on the inner surface of the trachea play a crucial role in maintaining respiratory cleanliness. They are involved in trapping and removing dust particles and microbial contaminants that are captured in the mucus secreted by epithelial cells. The cilia move rhythmically to push this mucus upwards towards the throat, where it is either swallowed or coughed out as phlegm, thus keeping the air passages clean.
A lymphocyte is most likely to encounter its specific antigen when it is in the
bone marrow
spleen
thymus
cardiac muscle
2. Spleen.
The spleen functions primarily as a filter for blood and plays a significant role in the immune system. It is here where lymphocytes are likely to encounter their specific antigens, as it acts as a site for immune responses to blood-borne pathogens. In contrast, the bone marrow and thymus are primarily involved in the production and maturation of lymphocytes, rather than antigen exposure, and the cardiac muscle is not directly involved in the immune system's response to pathogens.
Which one of the following statements is correct with respect to AIDS?
A) Drug addicts are least susceptible to HIV infection.
B) AIDS patients are being fully cured with proper care and nutrition.
C) HIV can be transmitted through eating food together with an infected person.
D) Causative HIV retrovirus attacks helper T-lymphocytes, thus reducing their numbers.
The correct answer is D: Causative HIV retrovirus attacks helper T-lymphocytes, thus reducing their numbers.
AIDS stands for Acquired Immuno Deficiency Syndrome indicating a deficiency in the immune system that is acquired during an individual's lifetime, rather than being congenital.
The mechanism in which HIV operates involves entering the helper T-lymphocytes, replicating itself, and producing progeny viruses. These progeny viruses are then released into the blood, where they continue to attack other helper T-lymphocytes. This leads to a progressive decline in the number of helper T-lymphocytes in the infected individual's body.
High-risk groups for HIV infection include individuals with multiple sexual partners and drug addicts who use intravenous drugs.
Since there is no cure for AIDS, prevention remains the most crucial approach.
Routes of HIV transmission include:
Sexual contact with an infected individual.
Transfusion of contaminated blood and blood products.
Sharing of infected needles, as seen among intravenous drug users.
From an infected mother to her child through the placenta.
Passive immunity is
A) inherited from the parent
B) acquired through the first exposure to the disease
C) achieved directly through ready-made antibodies
D) achieved through vaccination
The correct option is C) achieved directly through ready-made antibodies.
Passive immunity involves the direct acquisition of functional antibodies, rather than their production by the individual's immune system. This immunity can occur naturally (e.g., when maternal antibodies are transferred to the fetus through the placenta) or artificially (e.g., through the administration of high levels of antibodies specific for a pathogen or toxin, sourced from humans or animals).
Innate immunity differs as it is based on genetic predispositions and does not involve the transfer or creation of antibodies. On the other hand, acquired or adaptive immunity involves developing immunity through exposure to pathogens or by vaccination, leading to the body creating its own antibodies, a process referred to as active immunity.
Disorders caused due to thyroid hormone deficiency include: A. Cretinism B. Gull's disease C. Graves' disease D. Simple goitre
A) A, B, D
B) B & C
C) A, B, D
D) B, C, D
The correct answer is C) A, B, D.
Cretinism, Gull's disease, and simple goitre are all associated with hypothyroidism. Cretinism manifests in infants, leading to conditions such as dwarfism and mental retardation. Gull's disease, also known as myxoedema, typically occurs in adults and is characterized by symptoms like facial oedema and lethargy. Simple goitre arises due to an iodine deficiency, which is crucial for thyroid hormone production.
On the other hand, Graves' disease is a result of hyperthyroidism, marked by symptoms such as exophthalmia (eye bulging), weight loss, and increased restlessness. This disease is not related to a deficiency but rather an excess of thyroid hormone.
Which disease is caused in human beings due to depletion of the ozone layer in the atmosphere?
The disease caused in humans due to the depletion of the ozone layer is skin cancer.
AIDS can be prevented by:
A) Not touching the infected person
B) Not having sexual contact with the infected person
C) Not sharing needles and syringes with the infected person
D) Blood transfusion from the infected person
The correct answers are:
B) Not having sexual contact with the infected person
C) Not sharing needles and syringes with the infected person
Reasoning:
Option B highlights avoiding sexual contact with an infected person. HIV can be transmitted through direct contact with bodily fluids during unprotected sexual activities. Utilizing safe sex methods, like using condoms and maintaining monogamous relationships, can substantially reduce the risk of transmitting HIV.
Option C emphasizes not sharing needles and syringes. HIV can be spread through sharing syringes or needles that are contaminated with the virus. The promotion of single-use, disposable syringes, particularly in medical and similar settings, ensures a reduced transmission risk.
Additional Considerations:
Medical institutions reliably screen blood products for HIV, which helps prevent the virus from spreading through blood transfusions.
It's vital to note that simply touching an infected person does not transmit HIV, as the virus does not survive long outside the body and is not spread via casual contact.
Symptoms of a disease include excessive thirst, frequent urination at night, loss of weight, and fatigue. Which disease is this?
A. Uremia
B. Arthritis
C. Goitre
D. Diabetes
The correct answer is D. Diabetes.
Diabetes results from the malfunctioning of the pancreas, an organ responsible for producing insulin. Insulin is crucial for regulating blood sugar levels. When the pancreas does not function properly, it leads to an increase in sugar levels both in the blood and urine, causing symptoms such as excessive thirst, frequent urination at night, loss of weight, and fatigue.
Pair the following diseases with the respective organ/organ system they affect.
Column A | Column B |
---|---|
(1) Cholera | (a) Nervous system |
(2) Pneumonia | (b) Lungs |
(3) Tetanus | (c) Small intestine |
(A) 1-a, 2-b, 3-c
(B) 1-b, 2-a, 3-c
(C) $1- \mathrm{c}, 2- \mathrm{a}, 3- \mathrm{b}$
(D) $1- \mathrm{c}, 2- \mathrm{b}, 3- \mathrm{a}$
The correct option is (D) 1-c, 2-b, 3-a.
Cholera is a bacterial disease caused by Vibrio cholerae. This bacterium enters our bodies primarily through contaminated water or food and specifically targets the small intestine. The bacteria release a toxin that compels the body to secrete excess water and salts, leading to symptoms such as diarrhea and dehydration.
Pneumonia is triggered by the bacteria Streptococcus pneumoniae and impacts the lungs. It causes the lung tissues to become inflamed, leading to difficulties in breathing due to the reduced capability of the lungs to transfer oxygen.
Tetanus arises when a wound gets contaminated with spores of the bacterium Clostridium tetani, commonly present in soil. Upon entering the body, these spores produce a toxin that affects the nervous system, resulting in severe muscle spasms and nervous system disorders.
Which one of the following pairs of diseases is viral and transmitted by mosquitoes?
A Elephantiasis and dengue
B Yellow fever and sleeping sickness
C Encephalitis and sleeping sickness
D Yellow fever and dengue
The correct answer is D Yellow fever and dengue.
Yellow fever and dengue are both viral diseases transmitted by the Aedes aegypti mosquito.
Elephantiasis is caused by filarial worms, and although it is mosquito-borne, it is not viral.
Sleeping sickness is not mosquito-borne but transmitted by the tsetse fly and caused by a protozoan, Trypanosoma.
Encephalitis can be due to viral or bacterial infections and might be mosquito-borne or result from an autoimmune disorder; however, not all forms are mosquito-transmitted.
Which of the following is an example of an acute disease?
A. Common cold B. AIDS C. Cancer
The correct answer is A. Common cold.
An acute disease is characterized by its short duration and rapid development, often leading to recovery without long-term effects. Examples include the common cold and cough. In contrast, diseases such as AIDS and cancer are long-term, chronic conditions.
Khevna prefers to serve her granddad with sugar-free tea. What could be the disease her granddad is suffering from?
A. Cholera
B. Dysentery
C. Jaundice
D. Diabetes
The correct answer is D. Diabetes.
Diabetes is a medical condition characterized by elevated glucose levels in the blood over an extended period. This disease arises when the body is incapable of efficiently utilizing glucose, which is vital for energy production in cells. The regulation of blood sugar levels is managed by insulin, a hormone produced by the pancreas. Diabetes may develop due to insufficient insulin production or when the body's cells fail to respond adequately to the insulin. Consuming sugar-free foods is recommended to help manage and control blood sugar levels.
The AIDS test is known as:
A) ELISA
B) Australian antigen
C) HIV test
D) None of these
The correct answer is A) ELISA.
ELISA (Enzyme Linked Immunosorbent Assay) is a widely used method for detecting the Human Immunodeficiency Virus (HIV) that causes AIDS. This technique utilizes antibodies to identify the presence of an antigen associated with the virus.
There is a decrease in _____________ when a person is infected by the dengue virus.
A. RBC count
B. WBC count
C. platelet count
D. plasma
The correct answer is C. platelet count.
When a person is infected with the dengue virus, there is a notable decrease in the platelet count. This decrease weakens the body's immune response and can potentially lead to severe health issues. Low platelet count is a critical concern because it affects the blood's ability to clot, which in severe cases can be fatal.
Read the following statements (A-D): (A) Colostrum is recommended for the newborn because it is rich in antigens. (B) Chikungunya is caused by a Gram-negative bacterium. (C) Tissue culture has proved useful in obtaining virus-free plants. (D) Beer is manufactured by distillation of fermented grape juice.
How many statements are incorrect?
A) Two
B) Three
C) Four
D) One
The correct option is B) Three
Here's a breakdown of the accuracy of each statement:
Statement (A) states that colostrum is recommended for newborns because it is rich in antigens. This is incorrect because colostrum is valuable primarily due to its high concentration of antibodies, not antigens, which help in strengthening the immune system of the newborn.
Statement (B) claims that Chikungunya is caused by a Gram-negative bacterium. This is incorrect as Chikungunya is actually caused by a virus, not a bacterium.
Statement (C) mentions that tissue culture is useful in obtaining virus-free plants. This is correct. Utilizing tissue culture techniques, especially meristem culture, can indeed produce plants free of viruses. This result is achievable since the meristematic cells, typically not affected by viruses, can develop into new, virus-free plants.
Statement (D) suggests that beer is made by distillation of fermented grape juice. This is incorrect. Beer is produced through the fermentation of primarily barley (and sometimes other grains), not grape juice, and it does not involve the distillation process; that process is used in spirits production.
Thus, statements A, B, and D are incorrect, and statement C is correct. Therefore, three statements are incorrect.
Diseases caused by one or more abnormalities in the genome are known as:
A. Deficiency B. Genetic C. Metabolic D. None of the above
The correct answer is B. Genetic.
Genetic disorders are diseases caused by one or more abnormalities in the genome. These disorders can be very rare, often affecting one person in several thousand or even millions. Many of these conditions are hereditary, meaning they are transmitted from parents to their offspring.
Which of the following diseases are caused by viruses containing DNA as their genetic material?
A) Smallpox
B) Chickenpox
C) HIV
D) Herpes
The diseases caused by viruses with DNA as their genetic material include:
A) Smallpox
B) Chickenpox
D) Herpes
Viruses can either contain DNA or RNA as their genetic material. The diseases listed above, Smallpox, Chickenpox, and Herpes, are all caused by viruses that have DNA. In contrast, HIV (option C) is caused by a virus that has RNA as its genetic material, hence it does not belong to this list.
Jaundice is an illness that can be cured easily.
A) True
B) False
The correct answer is B) False.
Jaundice is not an illness that can be cured easily. It is essential to consult a doctor and adhere to the recommended medical advice, which may include complete rest for three weeks. Additionally, dietary adjustments are crucial, specifically limiting the intake of oily foods and products containing ghee or butter.
Distinguish between symptoms and signs of a disease.
Symptoms and signs of a disease are both indicators of health issues but differ in a few important ways:
Symptoms:
Subjective experiences felt by the patient.
Can suggest the presence of many different diseases.
Common examples include headache, nausea, shivering, and muscle fatigue.
Signs:
Objective indications observable by others.
Typically distinct and specific to particular diseases.
Examples include swelling, bleeding, and fractures.
In essence, symptoms are felt only by the patient and often cannot be measured directly, whereas signs can be seen or measured and are evident to healthcare providers or others observing the patient.
Ranikhet disease is concerned with:
A) cattle
B) fish
C) poultry
D) silk moth
The correct answer is C) poultry.
Ranikhet disease, also known as Newcastle Disease or Doyle's disease, is a serious condition that affects poultry. Below are key points about this disease:
Ranikhet disease is an acute, infectious, and highly contagious condition observed primarily in fowls.
The disease showcases symptoms such as respiratory distress and neurological issues, and it typically results in high mortality.
It is caused by the Newcastle Disease Virus (NDV).
This disease poses a significant threat to the global poultry industry, impacting not only chickens but also turkeys, pigeons, crows, ducks, geese, and other similar birds.
Besides poultry, it can affect other bird species including koel pheasants, guinea-fowl, partridges, and doves.
The avian influenza virus is spread to humans from
A) mice
B) birds
C) horses
D) cows
The correct option is B) birds.
Avian influenza virus, also known as bird flu, is transmitted to humans from birds. Infection can occur through direct contact with infected birds or by handling or consuming infected poultry.
What do ancient Ayurvedic books talk about?
A) They talk about medicine.
B) They talk about how humans can lead a balanced life.
C) They talk about how humans can lead a stressful life.
D) They talk about how humans can lead a healthy life.
The correct options are A, B, and D.
Option A: Ancient Ayurvedic books extensively discuss medicine, which is a core aspect of Ayurveda, the traditional Indian medical system.
Option B: These texts also provide insights on how individuals can maintain a balanced life, emphasizing both physical and mental well-being.
Option D: Furthermore, they address ways to lead a healthy life, including dietary guidelines, lifestyle choices, and preventive healthcare measures.
Ancient Ayurvedic texts like the Charaka Samhita and the Sushruta Samhita form the bedrock of Ayurvedic medicine, teaching not only therapeutic interventions for various ailments but also preventive measures to maintain overall health and balance in life.
Anxiety and eating spicy food together in an otherwise normal human may lead to:
A Diarrhea
B Vomiting
C Indigestion
D Jaundice
The correct answer is C Indigestion.
Anxiety and eating spicy food together in an otherwise normal individual can commonly result in indigestion.
Hygiene relates to:
A) Keeping dirty
B) Keeping clean
C) Eating junk food
D) None of these
The correct answer is B) Keeping clean.
Good hygiene is essential as it helps in maintaining both our physical environment and our body in a clean state. This practice is crucial for minimizing the chances of illness and preventing the spread of diseases.
What is Kessler Syndrome?
A. A disease where humans talk while sleeping.
B. A rare viral disease causing respiratory problems.
C. A problem found in space launch vehicles.
D. Proliferation of space debris in low Earth orbit.
The correct answer is D. Proliferation of space debris in low Earth orbit.
Kessler Syndrome, also known as the Kessler effect, is a scenario where the density of objects in Low Earth Orbit (LEO) is high enough to cause collisions between objects. This was proposed by NASA scientist Donald J. Kessler in 1978. Each collision generates more space debris, which then increases the likelihood of further collisions.
This cascading effect could make space exploration and satellite usage unfeasible for many generations due to the dense distribution of debris in orbit.
Which of the following factors can increase chances of spread of airborne diseases?
A. Overcrowded conditions
B. Poor ventilation
C. Poor drinking water quality
D. Sexual intercourse
The correct options that can increase the chances of the spread of airborne diseases are:
A. Overcrowded conditions
B. Poor ventilation
Airborne diseases spread via tiny pathogens in the air, which can originate from an infected person’s respiratory droplets. Overcrowded conditions create a scenario where people are in close proximity to each other, highly increasing the possibility of inhaling these droplets. Additionally, poor ventilation in a space hinders the circulation of fresh air; thus, airborne pathogens are more likely to stay in the air longer and be breathed in by healthy individuals. These environments are conducive to the spread of diseases like tuberculosis.
In higher vertebrates, the immune system can distinguish self-cells and non-self. If this property is lost due to a genetic abnormality and it attacks self-cells, then it leads to:
A) Allergic response
B) Graft rejection
C) Autoimmune disease
D) Active immunity
The correct answer is C) Autoimmune disease.
When the immune system fails to differentiate between self-cells and non-self due to a genetic abnormality, and begins to attack the body's own cells, this results in an autoimmune disease. In this condition, the body's immune system erroneously targets and damages its own tissues.
Consider the following statements regarding H9N2 virus:
It is a subtype of a virus that causes bird flu.
Unlike nCoVID-19, which can be detected by serologic test, H9N2 virus cannot be detected by the test.
It has the potential to become human-to-human transmissible.
Which of the statements given above are incorrect?
A) 1 and 2 only
B) 2 only
C) 1 and 3 only
D) 1, 2 and 3
The correct option is B - 2 only.
Explanation:
Statement 1 is correct: H9N2 is indeed a subtype of the influenza A virus, which is known for causing various influenzas including bird flu. It was first identified from turkey flocks in Wisconsin, US, in 1966.
Statement 2 is incorrect: Serologic tests can detect antibodies against a microorganism in the blood, indicating exposure to that microorganism. In the case of H9N2, such tests have successfully identified the virus, as performed by the National Institute of Virology in Pune.
Statement 3 is correct: The H9N2 virus has shown potential for human-to-human transmissibility due to its characteristic of having human virus receptors like specificity. Although it is primarily of avian origin, the presence in poultry increases the chances of avian-to-human transmission, and there is theoretical potential for adaptation to enable easier human-to-human transmission, albeit currently limited in actual occurrence.
What is incorrect about ringworm disease?
A) It is caused by Trichophyton fungi.
B) Constant itching results in the lesions getting worse.
C) It is transmitted by using objects touched or used by an infected person.
D) It is caused by the secretion of serotonin chemical.
Correct Answer: D
Statement: It is caused by the secretion of the serotonin chemical.
Serotonin primarily influences mood, behavior, appetite, digestion, sleep, memory, and other bodily functions. However, it has no role in causing ringworm infection. Ringworm is a fungal infection specifically caused by dermatophytes such as Trichophyton fungi, not by chemical secretions like serotonin. Hence, option D is incorrect regarding the cause of ringworm.
Unclean surroundings and unhygienic food habits cause disease.
A) True
B) False
The correct answer is A) True.
Unclean surroundings offer ideal conditions for the proliferation of pathogens, which are responsible for various diseases. Coupled with unhygienic food habits, these conditions significantly heighten our exposure to harmful pathogens, thus elevating the risk of disease transmission.
Examine the following statements: (i) None but the rich can afford air travel. (ii) Some of those who travel by air become sick. (iii) Some of those who become sick require treatment.
Which one of the following conclusions can be drawn from the above statements?
A. All the rich travel by air.
B. Those who travel by air become sick.
C. All rich persons become sick.
D. All those who travel by air are rich.
The correct option is D. All those who travel by air are rich.
From statement (i), "None but the rich can afford air travel," we can infer that only rich people have the ability to afford air travel. This can be expressed logically as: $$ \text{If someone travels by air, then they are rich.} $$ Thus, the direct conclusion is Option D: "All those who travel by air are rich."
We can verify that the other options:
A: "All the rich travel by air."
B: "Those who travel by air become sick."
C: "All rich persons become sick."
do not logically follow from the statements provided:
Option A is not justified because the original statement allows but does not require all rich people to travel by air.
Option B and C exceed the declarations of the latter two statements by asserting these outcomes as universal, whereas the premises state them only as possibilities (some, not all).
Hence, with the given premises, the most suitable conclusion is Option D.
Mental strain _____________ our health.
A does not affect
B adversely affects
C is good for
D is essential for
The correct answer is B adversely affects.
Mental strain adversely affects our health. Remaining in a state of worry, anxiety, or fear for prolonged periods is generally detrimental to one's well-being.
Match Column I with Column II and select the correct answer using the codes given below the columns.
Column I (Diseases) | Column II (Cause) |
---|---|
A. Smallpox | C. Malaria |
P. Bacteria | R. Deficiency of minerals |
B. Cholera | D. Anemia |
Q. Virus | S. Female mosquito |
A. A-S; B-Q; C-R; D-P
B. A-Q; B-P; C-S; D-R
C. A-S; B-R; C-Q; D-P
D. A-R; B-S; C-P; D-Q
The correct answer is B.
A-Q: Smallpox is caused by a virus.
B-P: Cholera is caused by bacteria.
C-S: Malaria is transmitted by the female mosquito and caused by Plasmodium.
D-R: Anemia is caused by a deficiency of minerals (specifically iron), resulting in low levels of hemoglobin.
Uric acid is the main excretory product of: (A) Insects (B) Birds (C) Terrestrial reptiles (D) Human beings
A A, B, and C are correct B A and B are only correct
C Only B and D are correct D Only A and C are correct
Uric acid is known to be the main excretory product of various organisms, particularly those looking to conserve water. The key advantage of excreting uric acid is its low toxicity and ability to be excreted in a solid state, which significantly minimizes water loss. This is especially crucial for organisms living in environments where water conservation is essential.
The organisms that primarily excrete uric acid include:
Insects
Birds
Terrestrial reptiles
These organisms convert their nitrogenous waste into uric acid, which is less toxic and conserves water by reabsorbing almost all the water during the excretion process. This makes uric acid an efficient excretory product for maintaining hydration in dry environments.
On the other hand, humans excrete urea rather than uric acid as the primary nitrogenous waste. Humans are referred to as "ureotelic" organisms because their main form of nitrogenous waste excretion is urea, which is different in composition and requires more water to be expelled.
Given this understanding, the correct answer to the question "Uric acid is the main excretory product of:" with the options being insects, birds, terrestrial reptiles, and human beings, would be: (A) Insects, (B) Birds, and (C) Terrestrial reptiles.
So the correct choice for the question provided would be: A) A, B, and C are correct.
If a rat is given an injection of sodium iodide with radioactive iodine, then in which of the following would most of the iodine be incorporated?
A. Cartilage
B. Thyroid
C. Parathyroid
D. Lymph nodes
The question asks where most of the iodine would be incorporated if a rat is given an injection containing sodium iodide with radioactive iodine. To address this, we need to consider the biological role and distribution of iodine in the body.
Iodine is crucial for the function of the thyroid gland, where it is used to synthesize thyroid hormones. These hormones play a significant role in the body, particularly in the metabolism of carbohydrates, fats, and proteins. If there is not enough iodine, the thyroid gland can enlarge, a condition known as goiter, due to a lack of thyroid hormone production.
Since iodine's primary function in the body centers around the thyroid gland’s role in hormone synthesis, the radioactive iodine in the injection would predominantly accumulate in the thyroid. This helps in tracing and confirming that the thyroid sapecifically uses iodine for hormone synthesis.
Thus, the correct answer to the question would be: B. Thyroid.
Involuntary muscles are not found in:
A) Iris
B) Bronchi of lung
C) Tongue
D) Heart
In the question provided, you are asked to identify where involuntary muscles are NOT found among the given options. Involuntary muscles are those that function without our conscious control, and they are not directly controlled by our brain or central nervous system.
Here's a breakdown of the options:
Option A: Iris
The iris contains two layers of smooth muscle, which are involuntary. Therefore, this option is incorrect.Option B: Bronchi of the lung
Involuntary muscles are not present in the bronchi of the lungs. So, this is the correct answer, as these muscles are not involved directly in the involuntary actions regulating respiratory functions which are controlled primarily by other parts of the respiratory system.Option C: Tongue
The tongue consists of multiple muscles and some of these are controlled voluntarily and others could potentially be influenced indirectly by involuntary reflexes. However, prominent control is voluntary, using skeletal muscles, which indicates that involuntary muscles as a primary component are not dominant here. Still, there are aspects of involuntary control in muscle actions related to reflexes yet primarily it's voluntary which could confuse with concerns to the question's phrasing.Option D: Heart
The heart prominently features involuntary muscle, specifically cardiac muscle which operates without conscious control.
The correct answer to the question "Involuntary muscles are not found in:" is Option B: Bronchi of the lung.
Which of the following is not controlled by the medulla in the hindbrain? A. Blood pressure B. Salivation C. Body posture D. Vomiting
Firstly, let's understand the role of the medulla. The medulla is part of the hindbrain and is responsible for managing various involuntary functions. These functions include activities that are not under conscious control, such as:
Blood pressure regulation
Salivation
Vomiting
These processes are crucial involuntary actions regulated by the medulla to maintain basic bodily functions without conscious effort.
On the other hand, body posture and balance are primarily managed by another part of the brain, known as the cerebellum. The cerebellum is crucial for coordinating voluntary movements, maintaining posture, and balance, ensuring smooth and balanced muscular activity.
Given this information, option C (Body posture) is the correct answer, as it is not controlled by the medulla but by the cerebellum. This is in contrast to blood pressure, salivation, and vomiting, which are indeed regulated by the medulla.
The brain is responsible for:
A. Thinking
B. Regulating the heartbeat
C. Balancing the body
D. All of the above.
The question pertains to the responsibilities of the brain. To understand this, let's delve into the function and the pivotal role that the brain plays in the human body.
The brain is a complex and large organ that essentially controls and regulates numerous functions and systems within the body. It involves a comprehensive network of neurons and synaptic connections that facilitate communication across the body. Neurologically, it operates with billions of neurons and trillions of synapses, making its task vastly intricate and highly coordinated.
When considering the specific responsibilities mentioned in the options:
Thinking: The brain is responsible for cognitive processes which include planning, problem-solving, perception, and decision-making among other intellectual functions.
Regulating the heartbeat: Through the autonomic nervous system, the brain helps to regulate the heartbeat, maintaining it within normal limits.
Balancing the body: It coordinates sensory input and motor functions that facilitate balance and physical coordination.
Thus, considering the roles specified, the answer to whether the brain is responsible for thinking, regulating the heartbeat, or balancing the body, can be established. Each option falls under the extensive umbrella of functionalities managed by the brain.
Therefore, the correct answer is: D. All of the above.
Which of the following diseases cannot be sexually transmitted?
A. Cholera
B. HIV/AIDS
C. Syphilis
D. Gonorrhoea
The question asks which of the given diseases cannot be transmitted sexually. To answer this, it's critical to understand the modes of transmission for each disease listed. The diseases provided are:
HIV/AIDS
Syphilis
Gonorrhoea
Cholera
HIV/AIDS, Syphilis, and Gonorrhoea are all well-known sexually transmitted diseases (STDs). HIV/AIDS is caused by the Human Immunodeficiency Virus (HIV), which can be transmitted through sexual contact, among other routes like blood transfusion and shared needles. Syphilis is caused by the bacterium Treponema pallidum, and its primary transmission route is through sexual contact, including both direct contact with a syphilis sore and other sexual activities. Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae and is also primarily spread through sexual contact, including vaginal, anal, and oral sex.
However, Cholera, which is a waterborne disease caused by the bacterium Vibrio cholerae, is typically spread through contaminated water or food, and not through sexual contact. Its primary mode of transmission is the ingestion of water or food contaminated with the Vibrio cholerae bacteria, which is quite different from the transmission of the STDs listed.
Therefore, the correct answer to the question, "Which of the following diseases cannot be sexually transmitted?" would be:
A. Cholera
In conclusion, cholera cannot be transmitted sexually, unlike HIV/AIDS, Syphilis, and Gonorrhoea, making it the correct choice in this context.
What is the time of rest in the heart? A. Never B. While sleeping C. Between two beats D. While doing yogasana
The question revolves around identifying when the heart is at rest. This might seem simple, but it’s important to understand the basic functionality of the heart to answer accurately.
The heart is a vital motor organ that plays the central role in the circulatory system. In humans, the heart is divided into four chambers, which supports a double circulation system ensuring efficient blood flow. The heart beats approximately 6200 times per minute in a normal, healthy individual.
Now, considering the options provided:
A. Never
B. While sleeping
C. Between two beats
D. While doing yogasana
It’s crucial to note that the heart never truly "rests" in the conventional sense, as it continuously pumps blood throughout the body, regardless of whether a person is awake, asleep, or engaging in any activities including yoga. Therefore, even during the brief moments between beats, the heart is involved in the cycle of contracting and relaxing, which is vital for blood circulation and not an actual rest.
Based on this understanding, the correct answer to the question "What is the time of rest in the heart?" is:
A. Never
This is because the heart is consistently active, working ceaselessly day and night to maintain the blood circulation necessary for the transport of gases and nutrients throughout the body.
Exchange of gases in humans occurs in:
A. Trachea
B. Pleura
C. Bronchi
D. Alveoli
The correct answer to the question regarding where gas exchange occurs in humans is option D: Alveoli.
The alveoli are the sites in the lungs where the exchange of gases occurs. Oxygen and carbon dioxide, along with other gases, are exchanged between the blood and the lung air spaces in these tiny sacs. This process happens across the alveolar membrane, which interfaces closely with the blood capillaries. Here, oxygen from the breathed-in air passes through the alveolar membrane and enters the blood in the capillaries, while carbon dioxide collected from the bloodstream is expelled back into the lungs to be breathed out.
Thus, while the trachea, pleura, and bronchi play essential roles in the respiratory system, they are not the locations of gas exchange. The alveoli, which are the functional units of the lungs, uniquely enable this critical process, making D (Alveoli) the correct answer.
Deficiency of one of the under mentioned vitamins causes cracking of lips in human beings:
A Vitamin A B Vitamin B2 C Vitamin K D Vitamin C
Cracking of lips in human beings, which is medically termed as cheilitis, can occur due to a deficiency of certain vitamins. The question we're addressing is which specific vitamin deficiency is primarily responsible for this condition.
Among the options provided:
Vitamin A mainly affects vision and skin health.
Vitamin C is important for the immune system and tissue repair.
Vitamin K is key for blood clotting processes.
However, Vitamin B2, also known as Riboflavin, directly contributes to the maintenance of healthy skin, including the lips. A deficiency in Riboflavin often results in cracked lips, amongst other symptoms such as sore throat and swelling of mucous membranes. This condition underscores the importance of maintaining adequate levels of Vitamin B2 in your diet.
Consequently, the correct answer to the question is:
B) Vitamin B2
Deficiency of vitamin A causes:
A. Beri-Beri
B. Anaemia
C. Night blindness
D. Scurvy
The question focuses on identifying a condition caused by the deficiency of Vitamin A. This particular vitamin deficiency presents a variety of symptoms, chief among which is night blindness. Night blindness, or difficulty seeing in dim light or in the dark, is a direct consequence of inadequate Vitamin A.
Let's break down the options given using the known deficiencies associated with other vitamins:
Beri-Beri: This is caused by a deficiency of Vitamin B1 (thiamine) and manifests as symptoms affecting the cardiovascular and neurological systems.
Anaemia: While there are different types of anaemia, Vitamin A deficiency is not a common cause. Iron, folate, or Vitamin B12 deficiencies are more typically linked to anemia.
Scurvy: As highlighted in the discussion, scurvy arises due to a lack of Vitamin C and is noted for symptoms like swollen, bleeding gums and reopening of previously healed wounds.
Therefore, the correct answer to the question "Deficiency of vitamin A causes:" is:
C. Night blindness
Sexually transmitted disease is:
A Malaria
B Diarrhoea
C AIDS
D Hepatitis
Firstly, to define a sexually transmitted disease, it is an infection that is predominantly transferred from one person to another through sexual contact. If an infected partner engages sexually with another, the infection can be transmitted to the second partner.
Let’s analyze the options:
Malaria is caused by the protozoa Plasmodium, and it is spread by the bite of an infected Anopheles mosquito, not through sexual contact. Thus, malaria is a vector-borne disease rather than sexually transmitted.
Diarrhoea can result from various causes including infections spread by contaminated food, water, or from person-to-person contact due to poor hygiene, but it is not classified as an STD.
Hepatitis (specifically types A and B mentioned in general understanding) can also be spread through contaminated food and water and some types through bodily fluids, but its primary association is not as a sexually transmitted disease.
AIDS (Acquired Immunodeficiency Syndrome), on the other hand, is caused by the Human Immunodeficiency Virus (HIV), which effectively attacks the white blood cells. AIDS/HIV can indeed be transmitted through sexual contact, making it a directly and commonly known sexually transmitted disease.
Hence, the correct answer is: C. AIDS
Deficiency of which hormone causes diabetes mellitus?
A. Thyroid
B. Insulin
C. Relaxin
D. Parathormone
Deficiency of the hormone insulin is primarily responsible for diabetes mellitus. Insulin plays a critical role in regulating blood glucose levels. When there is a deficiency or malfunction in insulin production or activity:
Blood sugar levels remain high, which can lead to various health issues.
To cope with insulin deficiency, artificial insulin is often prescribed to help maintain normal blood glucose levels in the human body.
It’s important to understand that insulin is produced by the pancreas and it helps decrease blood sugar levels by facilitating the uptake of glucose into cells. When insulin does not function correctly, glucose stays in the bloodstream, which results in high sugar levels, a condition known as hyperglycemia. This underlying issue of insulin deficiency or dysfunction leads to diabetes mellitus.
For your question regarding which hormone's deficiency causes diabetes mellitus, the correct answer is: B. Insulin.
The other options provided:
A. Thyroid: This hormone is related to growth and metabolism but not directly to the causal pathway of diabetes.
C. Relaxin: Mostly involved in pregnancy, affecting labor contractions and pelvic ligament relaxation.
D. Parathormone: This hormone regulates calcium levels in the blood and does not directly relate to diabetes.
Disease caused by virus, is: A. Malaria B. Diphtheria C. Chicken pox D. Leprosy
The question asks to identify which among the provided options is a disease caused by a virus. Let's analyze each option:
Malaria: This disease is caused by a group of protozoa known as Plasmodium. Therefore, it's not a viral disease.
Diphtheria: This is caused by a bacterium named Corynebacterium diphtheriae. So, it's also not a viral disease.
Chicken pox: This is indeed a viral disease caused by the varicella-zoster virus. It fits the asked criteria for being a viral disease.
Leprosy: Also known as Hansen's disease, leprosy is caused by the bacterium Mycobacterium leprae. Hence, it is not a viral disease.
Given the above analysis, the correct answer is: C. Chicken pox
Disease caused by deficiency of vitamin C is: A) Scurvy
The question is about identifying the disease caused by a deficiency of Vitamin C among the provided options. The disease associated with a lack of Vitamin C is Scurvy.
Scurvy is characterized by symptoms such as bleeding gums and difficulties with wound healing. It is crucially linked to Vitamin C deficiency because Vitamin C plays a significant role in the production and maintenance of collagen, which is vital for healthy skin, bones, and connective tissues.
Other mentioned deficiencies lead to different diseases:
Vitamin A deficiency causes night blindness or difficulty seeing in low light.
A deficiency in Vitamin B is known for causing problems like beriberi, which affects the nervous system.
Vitamin D deficiency is typically linked to issues such as weakened bones or conditions like rickets in children and osteomalacia in adults.
Thus, the correct answer here is: A) Scurvy
The causative agent of the disease sleeping sickness in human beings is an A) intracellular parasite found in RBC. B) extracellular parasite found in blood plasma. C) intracellular parasite found in WBC. D) platelets.
The causative agent of sleeping sickness in humans is a parasite belonging to the protozoa group. The specific parasite responsible for this disease is named Trypanosoma. This disease is particularly harmful as it attacks the human brain, leading to severe disruption in the sleeping patterns of the affected individuals. Some may experience prolonged sleep periods of up to 18-19 hours, while others might struggle to sleep at all. Apart from sleep disturbances, the disease severely affects other organs such as the heart, lungs, and kidneys, often resulting in serious complications.
Sleeping sickness is predominantly observed in regions such as Southern Africa, where the vector transmitting the disease, the tsetse fly, is commonly found. Importantly, Trypanosoma is an extracellular parasite that resides in the blood plasma, not inside the blood cells.
Thus, the correct answer to the question about the causative agent of sleeping sickness in humans is:
B) extracellular parasite found in blood plasma.
Prolonged exposure to the fumes released by incomplete combustion of coal may cause death of a human because of:
A. Inhalation of unburnt carbon particles. B. Continuous exposure to high temperature. C. Increased level of carbon monoxide. D. Increased level of carbon dioxide.
Prolonged exposure to fumes released by the incomplete combustion of coal can be extremely dangerous and potentially lethal due to one primary hazardous byproduct: carbon monoxide (CO).
In the scenario of incomplete combustion, there isn't sufficient oxygen to allow for the coal (which primarily consists of carbon) to burn completely. Ideally, with adequate oxygen, carbon would react to form carbon dioxide (CO₂). However, in oxygen-poor conditions, carbon only reacts with limited oxygen to form carbon monoxide, a much more dangerous compound.
The risk of carbon monoxide is mainly due to its ability to bind with hemoglobin in the blood. Hemoglobin typically carries oxygen throughout the body, but carbon monoxide binds to hemoglobin with a much greater affinity than oxygen. This binding produces a compound called carboxyhemoglobin, which significantly diminishes the blood's capacity to transport oxygen.
As a result, tissues and organs are deprived of oxygen, leading to oxygen depletion (hypoxia), which can fatally interrupt critical biological processes required for energy production and survival.
Hence, the correct answer to the question is: C. Increased level of carbon monoxide.
Always ensure that rooms where coal is burned are well-ventilated to prevent the serious risk posed by carbon monoxide accumulation.
Match the items in column I with those in column II, and select the correct choice
Column I | Column II |
---|---|
(A) Smallpox | (I) Bacteria |
(B) Cholera | (II) Virus |
(C) Malaria | (III) Deficiency of minerals |
(D) Anemia | (IV) Female mosquito |
A. $A-IV, B-II, C-III, D-I$
B. $A-II, B-IV, C-I, D-III$
C. $A-IV, B-III, C-II, D-I$
D. $A-II, B-III, C-I, D-IV$
To match each disease or condition from Column I with the appropriate cause or characteristic from Column II, we analyze as follows:
Smallpox is known to be caused by a virus. This matches (A) from Column I to (II) from Column II.
Cholera is caused by contamination with bacteria (Vibrio cholerae). Therefore, (B) matches with (I).
Malaria is transferred through female mosquitoes (specifically female Anopheles mosquitoes). This correctly links (C) to (IV).
Lastly, Anemia is often caused by a deficiency of minerals (iron deficiency being a common cause), so (D) should be matched with (III).
So, based on the items' connections:
(A) viruses => smallpox,
(B) bacteria => cholera,
(C) female mosquito => malaria,
(D) deficiency of minerals => anemia.
The correct choice from the options provided is:
Option B: $(A-II, B-I, C-IV, D-III)$
This matching sequence aligns with how each disease or condition is caused or characterized, confirming that option B is the correct answer.
Observe the flow chart below.
Which of the following best explains the observed results? A. Iodine helps to produce thyroxine B. Iodine inhibits thyroid gland activity C. Absence of iodine leads to starvation D. Iodine promotes cell growth and division
The flow chart indicates that tadpoles in water without iodine remain tadpoles, whereas tadpoles in water with iodine transform into frogs. This observation strongly supports the importance of iodine in the development and transformation of tadpoles into frogs.
Here’s the breakdown of the explanation:
Iodine plays a critical role in the production of thyroid hormones, including thyroxine, which is essential for normal growth and development in vertebrates like frogs.
Thyroxine, produced by the thyroid gland, influences the growth and development processes. In the absence of iodine, there is insufficient thyroxine, which leads to the halted development of tadpoles, preventing them from metamorphosing into frogs.
When iodine is present in the water, it facilitates the production of sufficient thyroxine, enabling the normal transformation from tadpole to frog.
Thus, the best explanation for the observed results in the flow chart is:
A. Iodine helps to produce thyroxine
This option is correct as it aligns with the known biological role of iodine in enabling the thyroid gland to produce thyroxine, which is essential for the growth and transformation observed in the tadpoles. The remaining options do not accurately explain the role of iodine based on the depicted results.
In the human body, the temperature control center is: A. Epithalamus B. Hypothalamus C. Thalamus D. Medulla oblongata
The correct answer to the question concerning the control center for temperature regulation in the human body is: B. Hypothalamus.
Here is a simplified explanation:
Epithalamus: This part of the brain is primarily connected with the limbic system and does not control body temperature.
Hypothalamus: This is the crucial area in the brain responsible for various autonomic functions, including temperature regulation. It actively works to maintain the body's homeostasis, or stable internal conditions, encompassing body temperature.
Thalamus: Acts mainly as a relay station for sensory and motor signals to the cerebral cortex, and not directly involved in temperature regulation.
Medulla Oblongata: Controls involuntary actions such as heartbeat and breathing, but does not regulate body temperature.
Thus, the right answer which identifies the temperature control center in the human body is Hypothalamus, making option B correct.
In which organ, bile juice formation takes place
A Liver
B Gall bladder
C Pancreas
D Stomach
The question posed is where bile juice formation occurs. The organ responsible for the production of bile is the liver. The liver is primarily known as the site where bile is produced. This bile is essential for breaking down fats into a simpler form. Once broken down, these fats dissolve more easily.
Additionally, the gallbladder acts as a storage site for bile, where it is held until needed.
The pancreas also plays a vital role in the body but is unrelated directly to bile production. It is involved in the secretion of other enzymes and insulin, which help manage blood sugar levels.
Furthermore, certain digestive enzymes are released in the stomach, which also contributes to the digestive process but, like the pancreas, is not involved in bile production.
Therefore, the correct answer to where bile juice formation occurs is the liver.
Cholera disease is caused by which pathogen:
A) Virus
B) Bacteria
C) Fungus
D) Protozoa
Cholera is a disease known for causing acute diarrhea. It is an illness centered around an infection of the intestines. The pathogen responsible for cholera is a toxigenic bacteria known as Vibrio cholerae. This bacterium creates a severe infection that can lead to the symptoms associated with cholera.
Given the options:
A) Virus
B) Bacteria
C) Fungus
D) Protozoa
The correct answer is B) Bacteria. Cholera is not caused by viruses, fungi, or protozoa, but by a bacterial agent.
Identify the symptoms of anaemia:
A. Pale skin
B. Diarrhea
C. Severe headache
D> Vomiting
Correct Options:
A. Pale skin
C. Severe headache
D. Vomiting
Explanation:
Anaemia is a medical condition characterized by a low haemoglobin count in the blood. Some of the common symptoms of anaemia include:
Pale skin
Severe headache
Vomiting
Chilling fever
In case of dengue and chikungunya, the insects bite during ______
A. daytime
B. night time
C. all the time
D. dawn and dusk
Correct Answer: A Daytime
Explanation:
The Aedes aegypti mosquito, which is a primary carrier for diseases like dengue and chikungunya, is known as a day-biting mosquito. This mosquito is most active during:
Approximately two hours after sunrise
Several hours before sunset
Additionally, these mosquitos tend to rest indoors during the day, often in dark places like closets.
Pick the odd one out based on the host organism.
Root rot
Rubella
Mosaic
Rust
The correct option is B Rubella.
Rubella is a human disease, whereas the others are plant diseases.
Mosaic: Viral plant disease.
Root rot: Fungal plant disease.
Rust: Fungal plant disease.
Thus, Rubella stands out as the odd one.
BCG vaccine is effective in children against which type of disease.
The BCG vaccine is administered to protect children from tuberculosis (TB). By receiving the BCG vaccine, children gain significant immunity against this disease and are less likely to contract TB.
What measures will you take if your friend is bleeding from nose?
A. Press her forehead
B. Press her nostrils
C. Blow her nose
D. Ask her to lie down
The correct option is B: Press her nostrils.
When dealing with a nosebleed, follow these steps:
Make the victim sit upright on a chair while leaning forward. This helps prevent blood from flowing down the throat which can cause choking or vomiting.
Press the nostrils firmly with fingers until the bleeding ceases. This helps in applying pressure to the bleeding vessel.
Apply an ice pack to the nose and forehead. The cold helps constrict blood vessels, which can stop the bleeding more quickly.
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Ask Chatterbot AINCERT Solutions - Human Health and Disease | NCERT | Biology | Class 12
What are the various public health measures, which you would suggest as safeguard against infectious diseases?
Various public health measures to safeguard against infectious diseases include:
Proper Disposal of Waste: Implement efficient waste management systems to prevent contamination and breeding grounds for pathogens.
Decontamination of Drinking Water: Ensure the purity of drinking water through regular testing and treatment to remove pathogens.
Control of Vectors: Implement measures to control vectors such as mosquitoes, including the use of insecticides, mosquito nets, and eliminating stagnant water where mosquitoes breed.
Vaccination and Immunization: Promote vaccination programs to build immunity in the population against common infectious diseases.
Public Hygiene: Maintain cleanliness in public spaces, including regular cleaning of water reservoirs, pools, cesspools, and tanks.
Health Education: Raise awareness about the importance of hygiene, vaccination, and other preventive measures through educational programs.
Screening and Early Detection: Implement programs for the early detection and treatment of infectious diseases to prevent their spread.
These measures are critical to reducing the incidence of infectious diseases and maintaining public health.
In which way has the study of biology helped us to control infectious diseases?
The study of biology has significantly helped us control infectious diseases in multiple ways:
Understanding Pathogens: Biology has enabled us to understand the nature and functioning of pathogens (bacteria, viruses, fungi, protozoans, helminths) that cause diseases.
Vaccination and Immunisation: Biological research has led to the development of vaccines that prepare the immune system to fight specific pathogens. Vaccination induces immunity, protecting individuals and populations from diseases such as polio, diphtheria, pneumonia, and tetanus.
Antibiotics and Drugs: The discovery and development of antibiotics and antiviral drugs have provided effective treatments to combat bacterial and viral infections. An example is the use of antibiotics to treat pneumonia caused by bacteria.
Diagnostic Methods: Techniques such as the Widal test for typhoid and ELISA for HIV help in the early detection and diagnosis of diseases, enabling timely treatment and preventing their spread.
Public Health Measures: Understanding the transmission and lifecycle of pathogens has guided public health measures such as vector control, sanitation, hygiene practices, and safe disposal of wastes to prevent diseases like malaria, amoebiasis, and ascariasis.
Biotechnology: Advances in biotechnology have led to the development of novel vaccines and genetically engineered drugs that are safer and more effective.
How does the transmission of each of the following diseases take place?
(a) Amoebiasis
(b) Malaria
(c) Ascariasis
(d) Pneumonia
(a) Amoebiasis
Amoebiasis is caused by the protozoan Entamoeba histolytica. It is transmitted through:
Contaminated food and water with fecal matter containing cysts of the parasite.
Mechanical carriers such as houseflies which transfer the parasites from feces to food.
(b) Malaria
Malaria is caused by the protozoan Plasmodium species. It is transmitted through:
Bite of an infected female Anopheles mosquito which introduces the infectious form (sporozoite) of the parasite into the human bloodstream.
(c) Ascariasis
Ascariasis is caused by the helminth Ascaris lumbricoides. It is transmitted through:
Ingestion of eggs present in contaminated soil, water, vegetables, and fruits.
(d) Pneumonia
Pneumonia is commonly caused by bacteria such as Streptococcus pneumoniae and Haemophilus influenzae. It is transmitted through:
Inhalation of droplets/aerosols from an infected person.
Sharing glasses and utensils with an infected person.
What measure would you take to prevent water-borne diseases?
To prevent water-borne diseases, you can take several important measures:
Ensure Clean Drinking Water: Always drink water from a safe and clean source. Use filters or purifiers if unsure about the quality of water.
Boil Water: Boiling water kills most bacteria and viruses. This is a simple and effective method to ensure the safety of drinking water.
Proper Disposal of Waste: Ensure proper disposal of human and animal waste to prevent contamination of water sources.
Use of Clean Containers: Store drinking water in clean, covered containers to prevent contamination.
Personal Hygiene: Practice good personal hygiene such as washing hands with soap and water before eating and after using the toilet.
Public Hygiene: Advocate for and participate in community efforts to maintain clean surroundings, such as regular disinfection of water reservoirs, pools, and tanks.
Avoid Stagnant Water: Prevent water stagnation around living areas to reduce breeding grounds for vectors like mosquitoes.
Sanitation: Use proper sanitation facilities and avoid open defecation.
Education and Awareness: Educate the community about the importance of clean water and proper sanitation.
Vaccination: In some cases, vaccination can provide protection against specific pathogens that cause water-borne diseases.
By implementing these measures, you can significantly reduce the risk of water-borne diseases.
Discuss with your teacher what does 'a suitable gene' means, in the context of DNA vaccines.
In the context of DNA vaccines, "a suitable gene" refers to a gene that codes for an antigen that elicits a protective immune response in the host without causing disease. Here are some key points to consider:
Antigen Selection: The gene must encode a protein that is recognized by the immune system. This antigen should be unique to the pathogen to distinguish it from the host's proteins.
Immunogenicity: The selected antigen should have the ability to stimulate both the B-cell (antibody-mediated) and T-cell (cell-mediated) immune responses.
Safety: The gene should not encode for any virulence factors that could cause disease or adverse effects in the host.
Stability and Expression: The gene should be stable within the DNA plasmid and should be efficiently expressed in the host cells after vaccination.
Cross-Protection: Ideally, the antigen should provide cross-protection against multiple strains or variants of the pathogen.
In summary, a suitable gene in DNA vaccines is one that ensures the production of a safe and effective immune response against the pathogen.
Name the primary and secondary lymphoid organs.
Primary Lymphoid Organs
Bone Marrow: The main lymphoid organ where all blood cells, including lymphocytes, are produced.
Thymus: A lobed organ located near the heart and beneath the breastbone; it provides micro-environments for the development and maturation of T-lymphocytes.
Secondary Lymphoid Organs
Spleen: A large bean-shaped organ that mainly contains lymphocytes and phagocytes; it acts as a filter of the blood by trapping blood-borne microorganisms.
Lymph Nodes: Small solid structures located at different points along the lymphatic system; they trap microorganisms or other antigens present in the lymph and tissue fluid, thereby activating lymphocytes.
Tonsils
Peyer's Patches: Found in the lining of the small intestine.
Appendix
Additionally, Mucosa-associated Lymphoid Tissue (MALT) constitutes about 50% of the lymphoid tissue in the human body and is located within the lining of major tracts like respiratory, digestive, and urogenital tracts.
The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:
(a) MALT
(b) $\mathrm{CMI}$
(c) AIDS
(d) $\mathrm{NACO}$
(e) HIV
(a) MALT: Mucosa-associated lymphoid tissue
(b) $\mathrm{CMI}$: Cell-mediated immunity
(c) AIDS: Acquired Immuno Deficiency Syndrome
(d) $\mathrm{NACO}$: National AIDS Control Organisation
(e) HIV: Human Immuno Deficiency Virus
Differentiate the following and give examples of each:
(a) Innate and acquired immunity
(b) Active and passive immunity
(a) Innate vs. Acquired Immunity
Feature | Innate Immunity | Acquired Immunity |
---|---|---|
Definition | Non-specific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. | Specific defense mechanisms that are tailored to precisely eliminate specific pathogens or antigens. |
Response Time | Immediate response (0-96 hours). | Slower response (days to weeks), involves a lag time between exposure and maximal response. |
Specificity | Non-specific; does not distinguish between different types of pathogens. | Highly specific to a particular pathogen; adapts to recognize specific antigens. |
Memory | No memory; response is the same with each exposure to the same pathogen. | Has memory; stronger and faster response upon subsequent exposures to the same pathogen. |
Components | Skin, mucous membranes, phagocytes, natural killer cells, inflammation, fever, complement system. | B and T lymphocytes, antibodies, antigen-specific receptors, memory B and T cells. |
Examples | Skin acts as a barrier to block the entry of pathogens. | Vaccination induces a memory response to a specific pathogen, enhancing protection against future infections. |
(b) Active vs. Passive Immunity
Feature | Active Immunity | Passive Immunity |
---|---|---|
Definition | Immunity developed by the body in response to exposure to a pathogen or to a vaccine containing the pathogen. | Immunity conferred by transferring antibodies or immune cells from an immune individual to a non-immune one. |
Source | Generated by the host’s own immune system after exposure to an antigen or vaccination. | Acquired from another individual or species that has already developed immunity against specific pathogens. |
Duration | Long-lasting; immune memory can last for years or even a lifetime. | Short-term; lasts only for a few weeks or months until the transferred antibodies are degraded. |
Development | Takes time to develop as the body needs to process the antigen and generate a specific immune response. | Immediate effect as the antibodies are introduced already formed into the body. |
Examples | Developing immunity after recovering from diseases like chickenpox or through vaccination against influenza. | Receiving anti-venom after a snake bite, or maternal antibodies transferred to a baby via breast milk. |
Draw a well-labelled diagram of an antibody molecule.
Here is a well-labelled diagram of an antibody molecule:
Labels:
Heavy Chains (H): Two longer peptide chains.
Light Chains (L): Two shorter peptide chains.
Antigen Binding Site: The region where the antigen binds to the antibody.
Constant Region (C): The part of the antibody's structure that remains constant.
Variable Region (V): The part of the antibody's structure that varies to accommodate different antigens.
This diagram represents the basic structure of an antibody, which plays a crucial role in the immune system by recognizing and binding to specific antigens.
What are the various routes by which transmission of human immunodeficiency virus takes place?
The transmission of Human Immunodeficiency Virus (HIV) occurs through various routes:
Sexual contact with an infected person.
Transfusion of contaminated blood and blood products.
Sharing of infected needles; this is common among intravenous drug abusers.
From an infected mother to her child through the placenta during pregnancy, childbirth, or breastfeeding.
These routes are highlighted in the AIDS section of the chapter.
What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?
The Human Immunodeficiency Virus (HIV), which causes AIDS, primarily targets the immune system, significantly reducing its effectiveness. After entering the body, HIV infects helper T-lymphocytes (T cells), which are crucial for immune response. The virus inserts its RNA into the host cell's DNA, prompting the cell to produce new virus particles. This viral replication leads to the eventual destruction of the T cells. Consequently, the infected individual experiences a dramatic decrease in immune competency, becoming susceptible to opportunistic infections. The loss of these vital cells impairs the body's ability to fight off diseases, leading to the weakened immune state characteristic of AIDS, marked significantly by reduced counts of helper T-lymphocytes.
How is a cancerous cell different from a normal cell?
Cancerous cells differ from normal cells in several key aspects:
- Uncontrolled Growth: Normal cells have regulated growth rates and stop growing when they make contact with other cells (contact inhibition). Cancerous cells lack this regulation and grow uncontrollably.
- Ability to Metastasize: Unlike benign cells that remain localized, malignant cancer cells invade nearby tissues and can spread to distant parts of the body (metastasis).
- Loss of Normal Functions: Cancer cells often lose the ability to perform the regular functions of the cell type from which they originate.
- Immortality: Normal cells have a lifespan and undergo programmed cell death (apoptosis), but cancer cells can evade apoptosis, leading to their immortality.
- Genetic Changes: Cancerous cells have alterations in their DNA that lead to these changes in growth and behaviour.
Explain what is meant by metastasis.
Metastasis refers to the process by which cancerous cells spread from their original site to other parts of the body. This is a hallmark of malignant tumors and distinguishes them from benign tumors. Here are key points regarding metastasis:
Primary Tumor: Cancer cells originate in a specific location, forming a primary tumor.
Spread: These cells break away from the primary tumor and enter the bloodstream or lymphatic system.
New Sites: Cancerous cells travel to distant organs or tissues, where they lodge and start to grow, forming secondary tumors.
Invasion: The cells invade and damage surrounding tissues at the new site.
Nutrient Competition: Metastatic cells compete with normal cells for nutrients, often leading to the starvation and death of normal cells.
Metastasis is considered one of the most dangerous characteristics of cancer because it makes the disease more difficult to treat and significantly worsens the prognosis.
List the harmful effects caused by alcohol/drug abuse.
The abuse of drugs and alcohol can lead to severe health, social, and psychological issues. Major health consequences include liver damage (cirrhosis), brain damage, heart problems, and an increased risk of cancer. Consuming these substances can lead to risky behaviors such as reckless driving, leading to accidents and injuries. Socially, abuse can result in broken relationships, social isolation, and issues with work and finances. Psychological effects involve depression, anxiety, and a higher risk of suicide. Those who use drugs intravenously may also face diseases like HIV and Hepatitis B due to needle sharing. Overdosage can lead to coma or fatal outcomes. Education, awareness, and timely intervention are crucial in managing these risks.
Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Yes, friends can significantly influence one's decision to take alcohol or drugs, particularly during adolescence and young adulthood. Peer pressure is a powerful force, as fitting in and feeling accepted are crucial during this stage. To protect oneself from such influence, it's important to choose friends wisely, opting for those who prioritize healthy habits and who respect your personal choices.
Setting clear personal boundaries is also crucial. Be confident in saying no and stay firm in your decisions despite peer pressure. Engaging in healthy and constructive activities like sports, arts, or volunteer work can also provide positive outlets and reduce the temptation to engage in harmful behaviours. Education on the dangers of drug and alcohol abuse is essential; understanding the risks helps resist peer pressure effectively.
Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.
Once a person starts taking alcohol or drugs, it becomes difficult to discontinue the habit due to addictive nature of these substances. They cause a physical and psychological dependence. This dependence is characterized by a strong craving for the substance and withdrawal symptoms upon cessation, making it challenging to quit. Repeated use leads to increased tolerance, requiring higher doses for the same effect, which escalates use. These substances also alter brain chemistry, particularly affecting the reward system, reinforcing the behaviors associated with use. The cycle of craving and relief from withdrawal symptoms becomes a compulsive pattern. Therefore, understanding these dynamics is crucial, and professional help in managing addiction is often necessary.
In your view what motivates youngsters to take to alcohol or drugs and how can this be avoided?
Curiosity, stemming from a natural desire to explore the unknown, often motivates youngsters to experiment with alcohol or drugs. Peer pressure also plays a significant role, pushing them to conform to group norms to feel accepted and valued. The need for escapism, whether from personal problems, stress, or the pressure to perform in academia or social settings, can drive youth toward substance use as a temporary relief.
To avoid this, open communication about the risks and consequences of substance abuse is crucial. Healthy alternatives for stress relief and recreation, such as sports, arts, and other hobbies should be encouraged. Strong support systems from family and peers can provide guidance and help youngsters resist negative influences. Education and awareness programs in schools can also effectively inform students about the dangers of drug and alcohol use.
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Notes - Human Health and Disease | Class 12 NCERT | Biology
Human Health and Disease Class 12 Notes: Comprehensive Guide
Understanding Health
A healthy state goes beyond just the absence of disease and encompasses complete physical, mental, and social well-being. When we are healthy, we are more efficient at work, resulting in higher productivity and economic prosperity. Good health also increases longevity and reduces infant and maternal mortality.
Common Diseases in Humans
Diseases can be broadly classified into infectious and non-infectious diseases.
Infectious Diseases
- Bacterial Diseases: Typhoid and pneumonia are caused by bacteria like Salmonella typhi and Streptococcus pneumoniae respectively.
- Viral Diseases: Common cold is caused by rhino viruses, which infect the nose and respiratory passage but not the lungs.
- Protozoan Diseases: Malaria, caused by Plasmodium, results in chills and recurring high fever.
- Helminthic Diseases: Ascariasis is caused by Ascaris, resulting in internal bleeding and intestinal blockage.
- Fungal Infections: Ringworm, caused by fungi like Microsporum, manifests as dry, scaly lesions on the skin.
Non-Infectious Diseases
- Genetic Disorders: These include deficiencies inherited from parents or those present from birth.
- Lifestyle Diseases: Conditions like diabetes and heart disease are often influenced by dietary habits, physical activity, and other lifestyle choices.
Immunity
Types of Immunity
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Innate Immunity: Present at birth and non-specific. It includes:
- Physical barriers: Skin and mucous membranes.
- Physiological barriers: Stomach acid, saliva, and tears.
- Cellular barriers: White blood cells like neutrophils and macrophages.
- Cytokine barriers: Proteins like interferons that protect non-infected cells.
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Acquired Immunity: Pathogen-specific and characterised by memory. It involves B-lymphocytes producing antibodies and T-lymphocytes aiding this immune response.
Vaccination and Immunisation
Vaccination introduces antigenic proteins or inactivated pathogens (vaccines) into the body, leading to the production of antibodies. This process generates memory B and T cells that can quickly recognise pathogens upon subsequent exposures, leading to faster and more effective immune responses.
Specific Diseases
AIDS
AIDS is caused by the Human Immunodeficiency Virus (HIV) and is transmitted through sexual contact, blood transfusions, shared needles, and from mother to child. It weakens the immune system, making the body susceptible to infections. Prevention includes safe sex practices, proper screenings before blood transfusions, and the use of disposable syringes.
Cancer
Cancer results from uncontrolled cell growth and can spread to other parts of the body (metastasis). It is caused by physical, chemical, and biological agents (carcinogens). Treatment includes surgery, radiation therapy, and chemotherapy, often in combination.
Drugs and Alcohol Abuse
Understanding Drug Abuse
Commonly abused drugs: Opioids (e.g., heroin), cannabinoids (e.g., marijuana), and cocaine. These drugs can lead to addiction and have severe physical and mental health consequences.
Alcohol Abuse: Leads to dependency and a host of health issues like liver damage and impaired cognitive functions.
Addiction and Dependence
Addiction is a psychological attachment to the effects of drugs or alcohol, while dependence includes physical withdrawal symptoms when the substance is not consumed.
Prevention and Control Measures
Personal Hygiene
Maintaining cleanliness, consuming clean water and food, and following healthy lifestyle habits are essential for disease prevention.
Public Health Measures
Proper waste disposal, decontamination of drinking water, and control of vectors like mosquitoes are necessary for maintaining public health.
Role of Education and Counselling
Parents and teachers play crucial roles in educating and counselling adolescents to resist peer pressure and avoid drug and alcohol abuse. Seeking professional help is vital for overcoming addiction.
Summary and Recap
Human health encompasses physical, mental, and social well-being. Preventive measures, maintaining personal and public hygiene, vaccinations, and understanding the role of immunity are essential in combating diseases. Education and counselling play significant roles in promoting healthy lifestyles and preventing drug and alcohol abuse.
By maintaining good health practices and being aware of potential health risks, you can lead a healthy and prosperous life.
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