Text Book Back Questions and Answers - Chapter 7 Human Health and Diseases 12th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

Human Health and Diseases

Text Book Back Questions and Answers

Question 1.
A 30 year old woman has bleedy diarrhoea for the past 14 hours, which one of the following organisms is likely to cause this illness?
(a) Streptococcus pyogens
(b) Clostridium difficile
(c) Shigella dysenteriae
(d) Salmonella enteritidis
Answer:
(c) Shigella dysenteriae

Question 2.
Exo-erythrocytic schizogony of Plasmodium takes place in __________
(a) RBC
(b) Leucocytes
(c) Stomach
(d) Liver
Answer:
(d) Liver

Question 3.
The sporozoites of Plasmodium vivax are formed from __________
(a) Gametocytes
(b) Sporoblasts
(c) Oocysts
(d) Spores
Answer:
(c) Oocysts

Question 4.
Amphetamines are stimulants of the CNS, whereas barbiturates are __________
(a) CNS stimulant
(b) both a and b
(c) hallucinogenic
(d) CNS depressants
Answer:
(d) CNS depressants

Question 5.
Choose the correctly match pair.
(a) Amphetamines – Stimulant
(b) LSD-Narcotic
(c) Heroin – Psychotropic
(d) Benzodiazepine – Pain killer
Answer:
(a) Amphetamines – Stimulant

Question 6.
The Athlete’s foot disease in human is caused by __________
(a) Bacteria
(b) Fungi
(c) Virus
(d) Protozoan
Answer:
(b) Fungi

Question 7.
Cirrhosis of liver is caused by chronic intake of __________
(a) Opium
(b) Alcohol
(c) Tobacco
(d) Cocaine
Answer:
(b) Alcohol

Question 8.
The sporozoite of the malarial parasite is present in __________
(a) saliva of infected female Anopheles mosquito.
(b) RBC of human suffering from malaria.
(c) Spleen of infected humans.
(d) Gut of female Anopheles mosquito
Answer:
(a) saliva of infected female Anopheles mosquito.

Question 9.
Where do the following events in the life cycle of Plasmodium takes place?
(a) Fertilization – __________
(b) Development of gametocytes – __________
(c) Release of sporozoites – __________
(d) Schizogony – __________
Answer:
(a) Fertilization – Gut of mosquito
(b) Development of gametocytes – Human RBC’s
(c) Release of sporozoites – From Mosquito to the human blood
(d) Schizogony – Human liver cells

Question 10.
Paratope is an __________
(a) Antibody binding site on variable regions
(b) Antibody binding site on heavy regions
(c) Antigen binding site on variable regions
(d) Antigen binding site on heavy regions
Answer:
(c) Antigen binding site on variable regions

Question 11.
Allergy involves __________
(a) IgE
(b) IgG
(c) IgA
(d) IgM
Answer:
(a) IgE

Question 12.
Spread of cancerous cells to distant sites is termed as __________
(a) Metastasis
(b) Oncogenes
(c) Proto-oncogenes
(d) Malignant neoplasm
Answer:
(a) Metastasis

Question 13.
AIDS virus has __________
(a) Single stranded RNA
(b) Double stranded RNA
(c) Single stranded DNA
(d) Double stranded DNA
Answer:
(a) Single stranded RNA

Question 14.
B cells that produce and release large amounts of antibody are called __________
(a) Memory cells
(b) Basophils
(c) Plasma cells
(d) killer cells
Answer:
(c) Plasma cells

Question 15.
Given below are some human organs.
Answer:
Identify one primary and one secondary lymphoid organ. Explain its role.
Liver, thymus, stomach, thyroid, tonsils Primary lymphoid organ – thymus Secondary lymphoid organ – tonsils Immunocompetency of T cells is achieved in Thymus Whereas tonsils help to fight viral and bacterial infections.

Question 16.
Name and explain the type of barriers which involve macrophages.
Answer:
Phagocytic barriers involves macrophages (monocytes, neutrophils) which phagocytose and . digest whole micro organisms.

Question 17.
What are interferons? Mention their role.
Answer:
Interferons are the antiviral proteins which induce antiviral state in the infected cells.

Question 18.
List out chemical alarm signals produced during inflammation.
Answer:
Serotonin, histamine and prostaglandins.

Question 19.
Explain the process of replication of retrovirus after it gains entry into the human body.
Answer:
After getting into the body of the person, the retrovirus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase. This viral DNA gets incorporated into the DNA of host cells and directs the infected cells to produce viral particles. The macrophages continue to produce virus and in this way acts like a HIV factory.

Question 20.
Explain the structure of immunoglobulin with suitable diagram.
Answer:
An antibody molecule is Y shaped structure that comprises of four polypeptide chains, two identical light chains (L) of molecular weight 25,000 Da (approximately 214 amino acids) and two identical heavy chains (H) of molecular weight 50,000 Da (approximately 450 amino acids). The polypeptide chains are linked together by di-sulphide (S-S) bonds. One light chain is attached to each heavy chain and two heavy chains are attached to each other to form a Y shaped structure. Hence, an antibody is represented by H₂ L₂ The heavy chains have a flexible hinge region at their approximate middles Antigen binding

Each chain (L and H) has two terminal They are C – terminal (Carboxyl) and amino or N-terminal. Each chain (L and H) has two regions. They have variable (V) region at one end and a much larger constant (C) region at the other end. Antibodies responding to different antigens have very different (V) regions but their (C) regions are the same in all antibodies. In each arm of the monomer antibody, the (V) regions of the heavy and light chains combines to form an antigen – binding

site shaped to ‘fit’ a specific antigenic determinant. Consequently each antibody monomer has two such antigen – binding regions. The (C) regions that forms the stem of the antibody monomer determine the antibody class and serve common functions in all antibodies.

Question 21.
What are the cells involved innate immune system?
Answer:
Cells involved in innate immunity are monocytes (macrophages), neutrophils, helper T-cells, B-cells, dendritic cells.

Question 22.
What is vaccine? What are its types?
Answer:
A vaccine is a biological preparation that provides active acquired immunity to a particular disease and resembles a disease causing microorganism and is often made from weakened or attenuated or killed forms of the microbes, their toxins, or one of its surface proteins. The vaccines are classified as first, second and third generation vaccines.

Question 23.
A person is infected by HIV. How will you diagnose for AIDS?
Answer:
A simple blood test is available that can determine whether the person has been infected with HIV. The ELISA test (Enzyme Linked Immunosorbent Assay) detects the presence of HIV antibodies. It is a preliminary test. Western blot test is more reliable and a confirmatory test. It detects the viral core proteins. If both tests detect the presence of the antibodies, the person is considered to be HIV positive.

Question 24.
Autoimmunity is a misdirected immune response. Justify.
Answer:
Autoimmune diseases : Autoimmunity is due to an abnormal immune response in which the immune system fails to properly distinguish between self and non-self and attacks its own body. Our body produces antibodies (auto antibodies) and cytotoxic T cells that destroy our own tissues. If a disease-state results, it is referred to as auto-immune disease. Thus, autoimmunity is a misdirected immune response.

Question 25.
List the causative agent, mode of transmission and symptoms for Diphtheria and Typhoid
Answer:

Question 26.
A patient was hospitalized with fever and chills. Merozoites were observed in her blood. What is your diagnosis?
Answer:
Appearance of merozoites in a patients blood may be an indication of malarial parasite – plasmodium.

Question 27.

1. Write the scientific name of the filarial worm that causes filariasis.

2. Write the symptoms of filariasis.

3. How is this disease transmitted?

Answer:

1. Scientific name of the filarial worm – Wuchereria bancrofti

2. Symptoms of filariasis – Inflammation of lymph nodes, obstruction of lymph vessels causes elephantiasis of limbs, genital etc.

3. Mode of disease transmission : Vector transmission (female Culex mosquito)

Question 28.
List the common withdrawal symptoms of drugs and alcohol abuse.
Answer:
The withdrawal symptoms may range from mild tremors or convulsions, severe agitation and fits, depressed mood, anxiety, nervousness, restlessness, irritability, insomnia, dryness of throat, etc, depending on the type of drug abuse.

Question 29.
Why do you think it is not possible to produce vaccine against ‘common cold’?
Answer:
Vaccines target specific pathogens and elicit immunity. In case of common cold, more than 200 strains of viruses are responsible for causing the disease. Hence it is practically difficult to develop vaccine against it.