Important Questions for Class 12 Biology 8th Chapter Human Health and Disease MCQ, Very Short, Short Type, Long Type
CBSE Class 12 Important Questions for Class 12 Biology Chapter 8 Human Health and Disease all MCQ Type, Very Short Type, Assertion Reason Type, Case Study, Short Type and Long Type Questions with Answers by Expert. Important Questions for Section A, B, C, D Class 12 Biology Chapter 8.
- MCQs
q.1) Assertion: chill and high fever recurring every three to four daysin malaria
Reason: The rupture of RBCs is associated with release of a toxic substancehaemozoin
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
q.2) Assertion: The secondary lymphoid organs are bone marrow and thymus
Reason: the major function of secondary lymphoid organs is maturation of immature lymphocytes
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
q.3) Transmission of HIV-infection generally occurs by all except
(a) sexual contact with infected person
(b) by transfusion of contaminated blood and blood products
(c) by sharing infected needles as in the case of intravenous drug abusers and
(d) by coughing or sneezing by aids infected individual
q.4) Assertion: Contact inhibition is the virtue by which contact with other cells inhibits their uncontrolled growth
Reason: Cancer cells appears to have the property of contact inhibition
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
q.5) The causative agent of filariasis is
a.) W. bancrofti
b.) Microsporum
c.) Trichophyton
d.) Epidermophyton
q.6) Assertion: it should be borne in mind that use of drugs even once, can be a fore-runner to addiction.
Reason: Thus, the addictive potential of drugs and alcohol, pull the user into a vicious circle leading to their regular use (abuse) from which he/she may not be able to get out.
a.) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.) Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion.
c.) If assertion is true but the reason is false.
d.) If both assertion and reason are false.
q.7) Which is very effective sedative and painkiller, and is very useful in patients who have undergone surgery?
a.) cocaine
b.) barbiturates
c.) amphetamines
d.) Morphine
q.8) A widely used diagnostic test for AIDS is
a.) Widal Test
b.)Enzyme linked immuno-sorbent assay
c.) MRI
d.) X-ray
q.9) physiological barriers of immunity include
a.)acid in stomach
b.) Mucus coating of the epithelium lining the respiratory
c.) Virus-infected cells secrete proteins called interferons
d.) types of leukocytes (WBC)
10) antibodies are produced by _________
a.) T cells
b.) B cells
c.) polymorpho-nuclear leukocytes
d.) natural killer
- Answer in one sentence
Q.1) Name the causative agent of disease pneumonia in humans?
Ans. Bacteria such as Streptococcus pneumoniae and Hemophilus influenzae cause pneumonia in humans.
Q.2) State the symptoms of Pneumonia
Ans. Pneumonia symptoms include fever, chills, cough, and headache. In severe cases, the lips and fingernails may turn grey or bluish.
Q.3) What is allergy and allergens?
Ans. Allergy is defined as an overactive immune system reaction to particular antigens in the environment. Allergens are the chemicals that elicit such an immunological response.
q.4) Name different species of plasmodium that cause malaria.
Ans. Different Plasmodium species i.e., Plasmodium vivax, Plasmodium malaria, and Plasmodium falciparum cause various kinds of malaria. Malignant malaria, caused by Plasmodium falciparum, is the most dangerous of all, and it can even be fatal.
q.5) State the function of secondary lymphoid organs
Ans. The secondary lymphoid organs serve as locations for lymphocytes to engage with antigen before proliferating to become effector cells.
Q.6) what is metastasis?
Ans. Splintered cells from tumour travel through the bloodstream to other parts of the body, where they create a new tumour. Malignant tumourhave the above feature and it is termed as metastasis.
q.7) what is biological response modifiers?
Ans. Biological response modifiers, such as -interferon, are administered to the patients, which boost their immune system and aid in the tumor’s destruction.
- Answer in short
Q.1) What are major factors which affect health of an organism?
Ans. (i) Genetic problems – deficiencies with which a child is born and deficiencies/defects inherited from parents from birth;
(ii) infections; and
(iii) lifestyle factors such as the food and water we consume, the rest and exercise we give our bodies, the habits we have or lack, and etc.
Q.2) Describe the causes of Cancer.
Ans. 1.) Physical, chemical, or biological factors can cause normal cells to transform into malignant neoplastic cells.
2.) These substances are known as carcinogens.
3.) Ionizing radiations such as X-rays and gamma rays, as well as non-ionizing radiations such as UV, induce DNA damage, which leads to neoplastic transformation.
4.) Tobacco smoke contains chemical carcinogens, which have been established as a primary cause of lung cancer.
5.) Oncogenic viruses, which cause cancer, have genes known as viral oncogenes.
6.) Furthermore, numerous genes known as cellular oncogenes or proto-oncogenes have been found in normal cells that, when activated under particular conditions, can lead to the cells’ oncogenic transformation.
Q.3) Describe the broad classification of disease?
Ans. 1.) Infectious and non-infectious diseases can be divided into two categories.
2.) Infectious diseases are diseases that can easily spread from one person to another.
3.) Infectious diseases are fairly frequent, and we all get sick from them at some point in our lives.
4.) Some infectious diseases, such as AIDS, are lethal.
5.) Cancer is the leading cause of death among non-infectious diseases. Abuse of drugs and alcohol has a negative impact on our health.
Q.4) What is the causative agent of typhoid? State its symptoms and portal of entry of typhoid.
Ans. 1.) Salmonella typhi is a pathogenic bacterium that causes human typhoid fever.
2.) These pathogens usually enter the small intestine by contaminated food and drink, and then travel to other organs via the bloodstream.
3.) The symptoms of this condition include a persistent high temperature (39° to 40°C), weakness, stomach pain, constipation, headache, and loss of appetite.
4.) In severe cases, intestinal perforation and death may result.
Q.5) Short note: amoebiasis
Ans. 1.) Entamoeba histolytica is a protozoan parasite that causes amoebiasis in humans.
2.) It lives in the large intestine (amoebic dysentery).
3.) Constipation, abdominal pain and cramps, faeces with extra mucus, and blood clots are all symptoms of this condition.
4.) Houseflies serve as mechanical carriers, transmitting the parasite from infected people’s faeces to food and food products, infecting them.
5.) The main sources of infection are contaminated drinking water and feces-infected food.
Q.6) What is active and passive immunity?
Ans. 1.) Antibodies are created in the host body when it is exposed to antigens, which can be living or dead microorganisms or other proteins.
2.) Active immunity is the term for this form of immunity.
3.) Active immunity is a slow process that requires time to fully activate.
4.) Active immunity is induced by purposely injecting germs during vaccination or by infectious organisms obtaining entry to the body during spontaneous infection.
5.) Passive immunity occurs when the body receives ready-made antibodies to protect it from outside invaders.
Q.7) What is tumor? state its types?
Ans. 1.) Cancerous cells simply continue to divide, resulting in tumor-like aggregates of cells.
Tumors are classified as benign or malignant.
2.) Benign tumours are benign tumours that stay in one place and do not spread to other parts of the body, causing little damage.
3.) On the other hand, malignant tumours are a mass of growing cells known as neoplastic or tumour cells.
- Answer in brief
Q.1) Describe the disease Ascaris in detail.
Ans. 1.) Some of the helminths known to be pathogenic to humans are Ascaris, the common round worm, and Wuchereria, the filarial worm.
2.) Ascariasis is caused by the intestinal parasite Ascaris.
3.) Internal bleeding, muscular discomfort, fever, anaemia, and intestinal blockage are all symptoms of these diseases.
4.) The parasite’s eggs are excreted in the faeces of infected people, contaminating soil, water, and plants.
5.) A healthy person gets this sickness through polluted water, veggies, fruits, and so on.
Q.2) Explain the barriers of Innate immunity?
Ans. the 4 barriers of immunity are as follows:
- Physical barriers: Our skin is the primary barrier that stops microorganisms from entering our bodies. The mucus coating of the epithelium lining the respiratory, gastrointestinal, and urogenital tracts also aids in the capture of germs entering our bodies.
- Physiological impediments: Microbial development is inhibited by stomach acid, saliva in the mouth, and tears in the eyes.
- Cellular barriers: Certain types of leukocytes (WBC) in human bodies, such as polymorphonuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (types of lymphocytes) in the blood and macrophages in tissues, can phagocytose and eliminate germs.
- Cytokine barriers: Infected cells secrete proteins known as interferons, which protect non-infected cells from future viral infection.
Q.3) What is mechanism behind auto immune disorders?
Ans. 1.) The ability to distinguish alien organisms (e.g., pathogens) from self-cells evolved memory-based acquired immunity in higher animals.
2.) This is caused by 2 parameters stated below
3.) Higher vertebrates, for example, can discriminate between alien molecules and foreign species.
4.) The majority of experimental immunology is concerned with this feature.
5.) apart from this, the body sometimes targets self-cells for unclear causes, such as genetics.
6.) Auto-immune disease is the result of this, and it causes damage to the body.
7.) Rheumatoid arthritis is an auto-immune illness that affects a large number of people in modern society.
q.4) describe the various lymphoid organs in detail?
Ans. 1.) All blood cells, including lymphocytes, are created in the bone marrow, which is the principal lymphoid organ.
2.) The thymus is a lobed organ that lies beneath the breastbone and near the heart.
3.) The thymus is relatively large at birth, but it gradually shrinks with age, eventually shrinking to a very tiny size by the time puberty arrives.
4.) Both the bone marrow and the thymus provide microenvironments for T-lymphocyte growth and maturation.
5.) The spleen is a bean-shaped organ with a huge size. Lymphocytes and phagocytes make up the majority of the cells.
6.) By capturing blood-borne microorganisms, it works as a blood filter.
7.) Lymph nodes are tiny solid structures that are distributed throughout the lymphatic system. 8.) Microorganisms or other antigens that get into the lymph and tissue fluid are trapped in lymph nodes.
9.) Antigens trapped in lymph nodes activate lymphocytes present in the lymph nodes, resulting in an immunological response.
10.) Mucosaassociated lymphoid tissue is lymphoid tissue found within the lining of the major passages (respiratory, digestive, and urogenital tracts) (MALT).
11.) It makes up around half of the lymphoid tissue in the human body.
q.5) Explain the mechanism of division of HIV virus in the human host.
Ans. 1.) The virus enters the person’s body and enters macrophages, where the virus’s RNA genome replicates to generate viral DNA with the help of the enzyme reverse transcriptase.
2.) This viral DNA is incorporated into the DNA of the infected cells, directing them to generate virus particles. The macrophages continue to produce virus, acting as an HIV factory.
3.) Next, HIV penetrates helper T-lymphocytes (TH), replicates, and produces more new viruses at the same time. Other helper T-lymphocytes are attacked by the progeny viruses produced in the circulation.
4.) This cycle is repeated, resulting in a gradual decline in the number of helper T cells in the infected person’s body.
5.) The person experiences fever, diarrhoea, and weight loss throughout this time.
6.) Because the number of helper T cells in the body decreases, the person becomes susceptible to infections that may normally be avoided, such as those caused by bacteria, particularly Mycobacterium, viruses, fungi, and even parasites like Toxoplasma.
7.) The patient’s immune system deteriorates to the point that he or she is unable to defend against these illnesses.