RBSE Class 12 Biology Important Questions Chapter 8 Human Health and Disease

Rajasthan Board RBSE Class 12 Biology Important Questions Chapter 8 Human Health and Disease Important Questions and Answers.

RBSE Class 12 Biology Chapter 8 Important Question Human Health and Disease

Multiple Choice Questions

Question 1.    
Antigens are present 
(a) inside nucleus
(b) on the cell surface
(c) inside cytoplasm
(d) on nuclear membrane
Answer:
(b) on the cell surface

Question 2.    
Which of the following is not a hereditary disease?
(a) Cretinism    
(b) Cystic fibrosis
(c) Thalassemia    
(d) Haemophilia
Answer:
(a) Cretinism

Question 3.    
Black lung disease is common is
(a) farmers
(b) refinery workers
(c) petrochemical industry
(d) coal mines
Answer:
(d) coal mines

Question 4.    
Antigen - binding site in an antibody is found between
(a) two light chains
(b) two heavy chains
(c) one heavy and one light chain
(d) either between two light chains or between one heavy and one light chain.
Answer:
(c) one heavy and one light chain

Question 5.    
Memory cells are formed from:
(a) monocytes    
(b) eosinaphils
(c) neutrophils    
(d) lymphocytes
Answer:
(d) lymphocytes

Question 6.    
Disease associated with secretion of toxin is
(a) TB    
(b) AIDS
(c) tetanurs    
(d) food poisoning
Answer:
(d) food poisoning

Question 7.    
BCG vaccine is a preventive measure against
(a) tuberculosis    
(b) typhoid
(c) AIDS    
(d) cholera
Answer:
(a) tuberculosis

Question 8.    
Kala azar is transmitted by
(a) sandfly    
(b) tse - tse - fly
(c) housefly    
(d) mosquitoes
Answer:
(a) sandfly

Question 9.    
Aflatoxin is produced by
(a) virus    
(b) fungus
(c) bactrian    
(d) nematode
Answer:
(b) fungus

Question 10.    
Which part of poppy plant yields opium?
(a) Latex from unripe capsules
(b) Dried roots
(c) Dried leaves
(d) Dried seeds 
Answer:
(a) Latex from unripe capsules

Question 11.    
In AIDS, which of affected?
(a) B - cells 
(b) T - cells
(c) Monocytes
(d) Neutrophils
Answer:
(b) T - cells

Question 12.    
Cancer cells are
(a) Hela cells
(b) CD4cells
(c) plasma cells
(d) Memory cells
Answer:
(a) Hela cells

Question 13.    
Screening test for AIDS is
(a) Western blot    
(b) ELISA
(c) PCR    
(d) Southern blot
Answer:
(b) ELISA

Question 14.    
The vector of break bone fever is
(a) Anopheles    
(b) Aedes
(c) Culex    
(d) None of these
Answer:
(c) Culex

Question 15.    
Ascaris is most commonly found in:
(a) men    
(b) women
(c) children    
(d) a and b
Answer:
(c) children

Question 16.    
Black foot disease is caused due to
(a) nitrate    
(b) fluoride
(c) arsenic    
(d) sulphur
(e) mercury
Answer:
(c) arsenic

Question 17.    
Bacterium, which is concerned with pertusis is:
(a) Bordetella pertussis
(b) Bacillus
(c) Diplococcus
(d) Mycobacterium tuberculum
Answer:
(a) Bordetella pertussis

Question 18.    
Hepatits - B is also called
(a) epidemic jaundice 
(b) serum jaundice 
(c) catarrhal jaundice 
(d) None of these 
Answer:
(b) serum jaundice 

Question 19.    
Which of the following pairs in correct?
(a) E. coli - Entamoeba hisolytica
(b) Culex - Elephatiasis
(c) Bed bug - kala azar
(d) Plasmodium - sleeping sickness.
Answer:
(b) Culex - Elephatiasis

Question 20.    
The main barrier that prevents the entery of microorganisms into our body is 
(a) antibodies    
(b) macrophages
(c) moncytes    
(d) skin 
Answer:
(d) skin 

Very Short Answer Type Questions

Question 1. 
A person free of disease is not necessarily healthy. Why?
Answer:
Health is a state of complete physical, mental and social well being and not merely absence of disease.

Question 2. 
What is disease?
Answer:
Any condition which interferes with the normal functioning of the body and impairs the health, is called disease.

Question 3.
Name two biological agents that cause disease.
Answer:

• Virus and 
• Bacteria.

Question 4. 
Name two diseases caused by bacteria.
Answer:

• Cholera - Vibrio cholarae
• Pneumonia - Streptococcus pneumoniae.

Question 5. 
Name two fungal disease.
Answer:

• Ringworm - Trichophyton
• Athlete’s food - Tinea rubrum.

Question 6. 
Name two protozoan disease and their causal organisms.
Answer:

• Malaria - Plasmodium vivax
• Kala - azar - Leishmania donovani.

Question 7. 
Name two viral disease and their causal viruses.
Answer:

• Chicken Pox - Varicella herpes virus
• AIDS - HIV virus.

Question 8. 
Name the vector of Kala azar and cholera
Answer:
Kala azar - sandfly (Phlebotomus)
Cholera - House fly (Musca domestica).

Question 9. 
Write the full form of ELISA and NACO 
Answer:
ELISA: Enzyme Linked Immuno - Sorbent Assay. 
NACO: National AIDS Cpntrol Organisation.

 
Question 10.
What is sporogony in malarial parasite?
Answer:
Sporogony is the phase of asexual multiplication of Plasmodium which occurs in the mosquito.

Question 11.
What is Cancer?
Answer:
Cancer is an abnormal and uncontrolled division of cells that invade and destroys the surrounding tissues. 

Question 12. 
Write two causes of cancer.
Answer:

• Chemical agents such as formaldehyde.
• Smoking and chewing tobacco.

Question 13.
Skin injury should not be neglected. Why? 
Answer:
The bacteria that causes tetanus and blood poisoning enter our body from the soil through cuts and injuries.

Question 14. 
Secondary immune response is very quick and intense. Why?
Answer:
The memory B - cells persisting from primary immune reaction quickly from antibodies to deal with microbes.

Question 15. 
Name two opioid and two canabinoid drugs.
Answer:
Opioid drugs - 

• morphine 
• Heroin

Canabinaoid drugs - 

• Ganja 
• Bhang. 

Question 16. 
How do cytokinin barriers help in evading viral infection?
Answer:
Cytokinin are virus infected cells which secreate protein called interferons. They protect non - infected cells from further viral infection by inhibiting their replication and making cells resistant to further infection.

Question 17. 
Retroviruses have DNA. However, the DNA of infected host cells does possess viral DNA. How is it possible?
Answer:
Retroviruses have RNA as their genetic material. After geting into the body of a person, the virus enters the mecrophages. Here RNA is replicated to form viral DNA by using enzyme reverse transcriptase. The viral DNA now, get incorporated into the host cell’s DNA and directs the infected cells to produce viruses.

Question 18. 
Write down the name of typhoid causing pathogen.
Answer:
Typhoid causing organism is Salmonella typhi. 

Question 19. 
Name two drugs obtained from poppy plant. “These drugs are medically useful but are often abused.” Taking the mentioned example” justified by giving reasons.
Answer:

• Morphine 
• Heroin.

Heroin is actually obtained by a cetylation of morphine. Thus, both heroin and morphine are related.. Morphine acts as an effective sedative and pain killer while heroin acts as depressant and slow down body functions.

Question 20. 
Suggest a method to ensure an anmnestic response in humans.
Answer:
Anamnestic response is the quick and intense response, which occurs when an individual encounters a particular antigen for the second time. It is added by the memory of primary response started in B - lymphocytes. By the administration of a died or attenuated pathogen in the body of person, a secondary immune response can Be ensured due to the presence of memory cells in the body.

Question 21. 
How do cytokine barriers provide innate immunity in humans.
Answer:
Cytokine barriers include interferons, which are secreted by virus infected cells. They provide protection to non - infected cells from further same viral infection. 

Question 22. 
Name two diseases whose spread can be controlled by the dication of Aedes mosquitoes.
Answer:

• Dengue fever and 
• Chikungunya are two diseases, whose spread can be controlled by the eradication of Aedes mosquitoes.

Question 23. 
Name any two physiological barriers that provide innate immunity.
Answer:

• Lysozyme - present in saliva, sweat, mumps etc.
• Cerumen - present in ear.

Question 24. 
State the function of interferons.
Answer:
Interferons protect non - infected cells from the other viral infected cells by releasing cytokine barriers.

Short Answer Type Questions - I

Question 1.
What are congenital diseases? Give two example of congenital diseases.
Answer:
Congenital disease are caused due to genetic disorder or abnormalities and are inherited from one generation to next generation. Hence they are called congenital diseases.
Example: 

• Sickle cells anaemia
• Haemophila.

Question 2. 
Differentiate between congenital diseases and acquired diseases with example.
Answer:
Differentiate between congenital diseases and acquired diseases:

Congenital Diseases	Acquired Diseases
1. They occur from birth.	1. They occur offer birth and during the life span of an individual.
2. They inherited from parents to offspring.	2. Not inherited.
3. Caused due to gene mutation or chromosomal mutations.	3. Caused due to pathogens or deficiency or nutrients or hormone etc.
4. Example : Haemophilia	4. Example : Typhoid.

Question 3. 
Differentiate between Acute diseases and Chronic diseases.
Answer:
Difference between Acute diseases and Chronic diseases:

Acute Diseases	Chronic Diseases
1. These occur very rapidly but last for only short period (e.g.) a few days).	1. These last for a long time and may be dangerous.
2. Do not cause major effect on general health and become well within a weak or so.	2. Have prolonged and major effects.
3. Example: common cold, cough.	3.Example: Tubuculosis, cancer.

Question 4. 
What is vector? Name the vectors who spread Trypanosoma and Wuchereria.
Answer:
Vectors: Vectors are those living organisms that spread pathogens from an infected person to a healthy person but themselves are not affected.

• Trypanosoma - Glossina (Tse - Tse fly)
• Wuchereria - Culex and Aedes mosquitoes. 

Question 5.
Name the causal organism of the following:
(i) plague 
(ii) cholera 
(iii) sleeping sickness 
(iv) athletic foot.
Answer:
(i) Plague - Posteurella pestis (Bacterium)
(ii) Cholera - Vibro Cholerae (Bacterium)
(iii) Sleeping Sickness - Trypanosoma gambiense (Protozoan)
(iv) Athlete’s foot - Tinea rubrum (Fungus)

Question 6. 
Certain pathogen are tissue / organ specific. Justify the statement with suitable example.
Answer:
Pathogen are tissue / organ specific because they have to adopt to the life within the environment of the host tissue or organs. For examples: 

1. Bacterium Salmonella typhi (typhoid causing bacteria) infects intetsine.
2. Protozoan Plasmodium (Malarial parasite) infects blood cell and liver cells.

Question 7. 
Many microbial pathogens enter the gut of human along with food. What are the preventive barriers to protect the body from such pathogens? What type of immunity do you observe in this case?
Answer:
Preventive barriers against microbes entering along with food:

• Saliva in mouth and HCl in gastric juice kill bacteria in food and prevent microbial growth in buccal cavity and stomach.
• The mucus secreted by goblet cells in lining of alimentary canal forms a coating on the epithelial lining of gut and traps microbes entering along with food. Immunity of this type called innate immunity.

Question 8. 
What does the terms ‘Memory’ of the immune system mean?
Answer:
After the human body has recovered from a disease, B - Lymphocytes produce memory cells that remain silent in the blood and attack the disease causing organism of it invades again. This second response is much quicker than the first response. As a result symptoms of the disease do not appear.

Question 9. 
Why cannabinoids are banned in sports and games?
Answer:
Cannobinoids are psychoactive chemicals such as hashish and marijuana. They are banned because they are performance enhancing and increase heart beat and reduce inhibition. Their use is banned in sport because this affacts atheletes performance.

Question 10.
Differentiate between antibodies and interferons.
Answer:
Difference between antibodies and interferons:

Antibodies	Interferons
1. Antibodies act slow.	1. Interferons act quickly.
2. Their period of action is long lasting.	2. Their period of action is temporary.
3. They act outside the cells.	3. They act inside the cells.
4. They act against bacterial and viral infection.	4. They act against only viral infection.

Question 11. 
What is innate immunity? How many types of barriers are present in innate immunity? Write down their names.    
Answer:
The immunity which is present from birth and is inherited from the parents is called innate immunity. The barriers'present in innate immunity:

• Physical Barriers: E.g., mucous membrane, Nasal hair, sweat etc.
• Physiological Barriers: E.g. Lysozyme, cerumen, bile, acidity of stomach.
• Cellular Barriers: E.g., WBCs, macrophage, natural killer cels etc.
• Cytokin Barriers: E.g., interferons.

Question 12. 
Name the causative organism of the disease amoebiasis. List three symptoms.
Answer:
The causativa organism of the diseases amoebiasis or amoebic dysentery is Entamoeba histolytica. It is found in large intestine of human.
Symptoms:

• Constipation.
• abdominal pain and cramps.
• Stool with excess mucous and blood clots.

Question 13. 
(a) Name the source plant of heroin drug. How is it obtained from the plant? 
(b) Write the effects of heroin on the human body.
Answer:
(a) Heroin is obtained from poppy plant (Papaver somniferum). It is extracted from the latex of the plant.
(b) Heroin is a depressant and slow down body function.

Question 14. 
Differentiate between the rates of B - lymphocytes and T - lymphocytes in generating immune response.
Answer:
B - Lymphocytes or B - cells produc an army of proteins (in response to pathogens) called antibodies in blood. Antibodies destroy antigens.

Question 15. 
It has often observed that the chances of a person suffering from measles in his or her lifetime are low if he or she has suffered from the disease in their early childhood. Justify the statement.
Answer:
A child who had suffered from measles in childhood may not contract disease in hir / her adulthood. It is because during the first encounter with pathogen (measles)specific antiboides (by humoral immune response are produced to counter to attack. During this attck memory cells are also produced. Due to this, on subsequent exposure to the same pathogen, the immune response is more rapid and intense. That is why, second exposure to the measles does not cause disease. It is known as acquired immunity of the body.

Short Answer Type Question - II

Question 1. 
Which are communicable diseases? Write any two ways for direct transmission of communicable diseases.
Answer:
The diesease which are caused by pathogen, and are transmitted form infected person to a healthy person are called communicable dieases. 
Ways for direct transmission:

1. Droplet Infection: Diseases like diphtheria, influenza, common cold etc. are spread by droplet infection (germs in tiny droplets of mucus) from sneezing, coughing spilting or even taking of infected reason.
2. Direct Contact: Some disease like chicken pox, leprosy, ring worm etc. are spread by physical contact between a infected person and a healthy person.

Question 2. 
Differentiate between infectious and non - infectious disease.
Answer:

Infectious or Communicable Diseases	Non - Infectious or Non - communicable diseases
1. These diseases are transmitted from infected person to healthy persons.	1. These diseases can not pass from one person to another person.
2. Causative means are micro - Organisms also called pathogens.	2. Brought about due to various reason.
3. Public health and domestic hygiene can reduce the incidence.	3. Counseling may be useful.
4. Examples: All viral, bacterial, protozoan, fungal and helminth diseases.	4. Examples: Cancer, vitamin deficiency, diabetes, Marasmus etc.

Question 3. 
Name the pathogen and their carrier for following diseases:
(i) AIDS 
(ii) Leprosy 
(iii) Tetanus 
(iv) Malaria 
(v) Tuberculosis
(vi) Aspergillosis.
Answer:

Infectious Diseases	Pathogens	Agents
1. AIDS	Human Immuno Deficiancy virus (HIV)	Direct contact
2. Leprosy	Mycobectruim leprae	Direct contact
3. Tetanus	Clostridium tetani	Soil
4. Malaria	Plasmodium spp.	Anopheles (female mosquito)
5. Tuberculosis	Mycobacteria tuberculosis	Air
6. Aspergillosis	Aspergillus fumigates	Airborn (conidia)

Question 4. 
Answer the question according to instruction.
(a) Typhoid: Pathogen name, mode of transmission, incubation period.
(b) Pneumbnia: Pathogen name, mode of transmission, incubation period.
Answer:
(a) It is common bacterial disease with world-wide distribution. It is epidemic in many parts of world. Its main cause of spread is poor sanitation and the presence of carriers. This disease is common in children of age of 1 - 15 years. However, it is found in adult also. In our country, it is a most common communicable disease. About 2.5 million people suffer from typhoid every year. 
Pathogen: Typhoid is caused by gram - negative, rode shaped, motile bacterium, Salmonella typhi.


Mode of Transmission (Epidemiology): The disease is spread by food and water contaminated with faeces of the patient. Houseflies may carry the pathogens from the faeces to the food, milk and water.
Incubation period: About 1 - 3 weeks.

Symptoms: Main symptoms of typhoid are:

• Common symptom of typhoid is high temperature about 103° - 104° F. Typhoid fever rises to the maximum in the afternoon. In first week, it increases with each day. Fever remains high in second week. But in third and fourth week, it gradually decreases.
• Sever body pain, headache, and stomach pain.
• Loss of appetite, constipation and inflammation in ileum and colon.
• Extreme weakness, coated tongue, liver and spleen become enlarged.
• In serves cases intestinal perforation and death may occur.

Preventive Measures (Prophylaxis):

• Proper community sanitation, cleaned and chlorinated water supply system and personal hygiene.
• Prevention of food contaminated by flies and dust.
• Cooks and food handlers in eating establishment should be pressed upon to wash their hand with soap and water before food handling.
• TAB - Vaccine provides immunity for about 3 years.
• Typhoral - oral vaccine should be given. 

Treatment: Typhoid fever can be diagnosed by 'Widal test’. Ampicillin and Chloromycetin are the effective drugs against typhoid. Long time treatment is necessary to completely eradicate typhoid bacteria.

(b) Pneumonia:
It is serious bacterial disease of lungs which affects mainly the infants and old people, but it can affect the people of any age.

Pathogen: In human beings pneumonia is caused mainly by Streptococcus pneumoniae commonly called Pneumococcus. Some other bacteria like Haemophiles influenzae, Diplococcus pneumoniae and Mycoplasma and viruses also cause pneumonia.

Epidemiology: A healthy person gets infection:

• By inhaling droplets released by the infected person in air.
• By sharing, glasses, utensil, food or water with an infected person.
• By bacterial cysts released with sputum of the infected person.

Incubation Period: Incubation period is about 1 - 3 days. 
Symptoms: Due to the infection, alveoli get filled with fluid, leading to severe problem in breathing. Difficulty in respiration is associated with many other symptoms, like:

• Fever, chills, cough and headache.
• In severe cases, lips and finger nails may turn grey to bluish in colour.
• Bloody and rusty sputum.
• Abdominal distension.

Prophylaxis: Isolation of the infected persons. 
Treatment: Pneumococci are identified by bile solubility test from bile, penicillin, ampicillin, erythzomycin etc. antibiotics are recommended in this diseases.

Question 5. 
Differentiate between B - lymphocyte and T - Lymphocytes.
Answer:

B - Lymphocytes (B - Cells)	T - Lymphocytes (T - cells)
1. This form humoral or antibody mediated immune system (AMIS).	1. These form cell - mediated immune system (CMIS).
2. These are differentiated in gut - associated bursal lymphoid tissues (tonsil, Peyer’s patches, appendix).	2. They are differentiated in thymus gland.
3. They form by division of plasma cells.	3. They form by division lymphoblasts of three types - killer, helper and suppressor cells.
4. Plasma cells do not move to the site of infection.	4. Lymphoblasts move to the site to infection.
5. They defend against some viruses, encapsulated bacteria and toxin that enter the blood and lymph.	5. They defend against viruses, protists, fungi and some bacteria which enter the cells.
6. Plasma cells donot react against transplant and cancer cells.	6. Killer cells react against transplants and cancer cells also.
7. Plasma cells secrete antibodies that pass into the blood and lymph and dispose off the antigens.	7. Killer cells on reaching the site of infection secrete perform that kills microbes by puncturing their cells membrane.
8. Plasma cells have no inhibitory role on immune system.	8. Suppressor cells inhibit the immune system form attacking body’s own cells.

Question 6. 
Differentiate between benign tumors and malignant tumors.
Answer:
Difference between benign tumors and malignant tumors:

Benign Tumors	Malignant Tumors
1. Benign tumors are single mass of cells enclosed in capsule.	1. Malignant tumors are mass of proliferating neoplastic cells without capsule.
2. Cells grow slowly.	2. Cells grow very rapidly.
3. Cells are non migratory, hence do not migrate from place of origin.	3. Cells have pseuopodia like processes, hence are migratory.
4. Cells remain combined to the site of their origin.	4. Cells invade and damage the surrounding normal tissues and lymphatic vessels to be carried to remote areas of body.
5. They are non - cancerous.	5. They are cancerous.

Question 7. 
“Prevention is better than cure.” Comment.
Answer:
“Prevention is better than cure,” means it is better to take care or check disease from happening. This can be supported by following examples:

1. We can keep our teeth and gums healthy by brushing teeth twice.
2. Malaria and dengue can be prevented by protecting from mosquito bite if house have netted doors and windows or there is stagnant water for mosquitoes to breed.
3. Stomach upset can be avoided by washing hand properly before eating or by not eating uncovered food.

Question 8. 
What are tranquilizers? Explain two of tranquilizers.
Answer:
Tranquillizers:
These are antianxiety drugs and as the name suggests peace the mind and relieve from worries. These bring relaxation, feeling of well being and may be some loss of inhibition but do not induce sleep or sedation. Tranquillizers are synthetic drugs. These are phenothiazines and benzodiazipines.

(a) Phenothiazines: These are antipsychotic drugs. In a psychotic patient, these drugs decrease aggressiveness and lower anxiety. Phenothiazine is the precursor compound for synthesis of  antipsyphotic drugs such as chloropromazine, thioridazine and reserpine etc. Reserpine is obtained from the roots of plant Rauwolfia species.

(b) Benzodiazipines: These are antianxiety drugs. These are mor popular barbiturates because these are more effective and almost no side effects and mild withdrawl symptoms. Benzodiazipines are precursor compounds for synthesis of many antiarixiety drugs like diazepam, oxazepam, chlonazepam, alprozolam and lerzepam.

The benzodiazepines are the worlds most highly used drugs. They produce their calming effect indirectly by increasing the action of Y - amino butyric acid. These drugs are available in the form of tablets, capsule and injections. But these should be taken in small doses and should be given when needed.
Withdrawal Symptoms: Withdrawal from tranquillizers can be as dangerous and painful as withdrawal from barbiturates. Combining the tranquillizing drugs with other, including alcohol is a highly dangerous form of abuse. Each drug, reinforce the effect of other drugs. Sudden pause after prolonged use results in insomnia, anxiety, irritability, restlessness, delirium, decreased appetite, sweating and trembling.
Rehabilitation: Gradual reduction of drug over a period of about 2 months under the supervision of physician.

Question 9. 
(i) Differentiate between benign and malignant tumors.
(ii) Why is colostrum a boon to the newborn baby. 
Answer:
(i) 

Benign Tumors	Malignant Tumors
1. Benign tumors are single mass of cells enclosed in capsule.	1. Malignant tumors are mass of proliferating neoplastic cells without capsule.
2. Cells grow slowly.	2. Cells grow very rapidly.
3. Cells are non migratory, hence do not migrate from place of origin.	3. Cells have pseuopodia like processes, hence are migratory.
4. Cells remain combined to the site of their origin.	4. Cells invade and damage the surrounding normal tissues and lymphatic vessels to be carried to remote areas of body.
5. They are non - cancerous.	5. They are cancerous.

(ii) The milk produced during the initial few days of lactation is called colostrum, which contains IgA antibodies. These are essential to develop resistance in newborn babies as they provide passive immunity. Thus, breast - feeding druing initial period of infant growth is recommended by doctors for bringing up a healthy baby.

Question 10. 
(a) It is generally observed that the children who had suffered from chicken - pox in their childhood may not contract the same disease in their adulthood. Explain giving reasons the basis of such an immunity in a individual. Name this kind of immunity.
(b) What are interferons? Mention their role.
Answer:
(a) A child who had suffered from chicken pox in childhood may not contract disease in his / her adulthood. It is because during the first encounter with pathogen (chicken pox virus) specific antibodies (By humoral immune response) are produced to counter the attack. During this attack, memory cells are also produced. Due to this, on subsequent exposure to the same pathogen, the immune response is more rapid and intense. That is why, second exposure to the chicken pox does not cause disease. It is known as acquired immunity of the body.

(b) Interferons are special type of proteins secrete by virus infected cells. They protect the healthy cells from the virus attacks.

Question 11. 
Name a human disease. Its causal organism, symptom (any three and vector spread by intake of water and food contaminated by human faecal matter. 
Answer:
Amoebiasis is a disease spread by intake of water and food contaminated by human faecal matter.
Causal organism: Entamoeba histolytica.
Symptoms: 

• Abdominal pain
• Constipation with cramp
• Faecal with excess mucus 

Vector: Housefly.

Question 12. 
Medically it is advisdedto all young mother that breast feeding is the best for their newborn babies. Do yo agree? Give reason in support of your answer.
Answer:
Yes, medically it is advised to all young mother that breast feeding is the best for their newborn babies. Because breast milk has valuable immunoglobulin which improves the immune power of the newborn. It has a good amount of Ig A initially along with water, fat, carbohydrates, protein, vitamins and mineral, amino acids, enzymes and white cells.

Question 13. 
(a) Name the causative agents of pneumonia and common cold.
(b) How do these differ in their symptom?
(c) Mention two symptoms common to both.
Answer:
(a) Pneumonia = Streptococcus pneumoniae
Common cold = Rhinoviruses
(b) Different Symptoms:

• Pneumonia: Chills, lips fingers turning grey to black, fluid in lungs.
• Common Cold: Infected nose and respiratory passage. Sore throat and horseness are common symptoms.

(c) Common Symptoms of Pneumonia and Common Cold: Cough and headache.

Question 14. 
(a) Write the scientific name of the causative agent and vector of malaria, and write its symptoms.
(b) Name any two diseases spread by Aedes sp.
Answer:
(a) The causative agent of malaria is Plasmodium. The species of Plasmodium may differ. It may be Plasmodium vivax, P. falciparum, P. ovale or P. malariae.
Vector: Anopheles mosquito (female).
Symptoms: High fever, chills and sweating.

(b) Aedes species of mosquito can lead to spreading of dangue and chickungunya.

Question 15. 
What are hallucinogens? Comments upon LSD and canabinoids.
Answer:
These are those drugs which change thought, feeling and perceptions of an individual who claims that he can ‘See Saunds’ and ‘hear Calour’. They have a strong effect on the cerebellum and sense organs. Besides they cause nightmares, floating sensation, chronic psychosis, dilation of pupil, increased sugar level in blood and increased frequency of urination. These drugs included LSD, Mescaline, psilocybin of products of Hemplant (Cannabis sativa) which include Charas, Ganja Bhang and Marijuana and some synthetic drugs like phencyclidine piperidine (PCP) Methylenedioxy Methamphetamine (MDMA).

LSD (Lysergic Acid Diethylamide): It is most dangerous hallucinogen causing chromosomal and foetal abnormalities. It causes Psychedelic effects in the concentration of pg/kg of body weight. LSD is derived from dried fruiting body, called Sclerotium of Ergot Fungus (Claviceps purpurea) parasitizing the ovary of flowers of rye. It also causes damage to CNS.

LSD causes floating sensation, chronic sensation, hallucination, high blood pressure, rapid heartbeat and high body temperature, vomiting and diarrhoea. It cause several mental disorders. Its continuous use causes chronic psychosis and damage to the CNS. It may cause ineome- sciousness and even death. The pathological, conditions caused by LSD or by eating grain affected by ergot is called ergotism.

Long Answer Types Questions

Question 1. 
Describe the disease common cold on the following heads:
(a) Pathogen
(b) mode of transmission
(c) Symptoms 
(d) prevention 
(e) Treatment. 
Answer:
(a) Pathogen: Common cold is one of the most common communicable disease. It is caused by several strains of Rhino viruses. There are more than 200 types of viruses which can cause common cold. This virus infects nose and nasal passage. Hence, it is also called pneumotropic viral disease. It does not infect the lungs.

(b) Mode of Transmission (Epidemiology): The infection transmits from discharge of nose or sneeze at an infected person inhaled directly. It also spread though contaminated object such as pens, books, door knobs, utensils etc.

(c) Symptoms: Following are symptoms of common cold:

• It is characterised by nasal congestion and discharge.
• Headache, restlessness,slight fever.
• Sore throat, harshness, cough, burning in nose.
• these characters lasts for 3 - 7 days.

(d) Prevention: These include:

• Avoid direct contact of infected person.
• Belongings of infected person should not be used. 

(e) Treatment: Common cold occurs in epidemic form.There is no particular treatment for common cold, mostly, antibiotics are given to check the secondary infection.

Question 2. 
Describe the schizogony in life cycle of malaria parasite.
Answer:
Life cycle of Malarial Parasite (Plasmodium vivax):
Life cycle of Plasmodium is complete in two hosts, hence called digenetic life cycle.    

1. The asexual part of the life cycle is completed in man, hence, man is regarded as the Secondary host (Earlier, man was considered as the primary host because gametocytes are formed in the human body).
2. The sexual cycle of Plasmodium is completed in female Anopheles mosquito. Hence, mosquito is considered as the primary host. Although mosquito acts as a vector in the spread of the diseases.

There are three phases of life cycle of Plasmodium:

1. Schizogony: Phase of asexual multiplication of Plasmodium inside human body.
2. Gamogony: Sexual phase which starts in man and is completed in mosquito.
3. Sporgony: An asexual multiplication in mosquito.

Asexual Phase of Life - Cycle in Man Inoculation of Infection in Man: Infected female Anopheles mosquito introduces sporozoites in the blood of a-healthy person along with its saliva while sucking human blood, The mosquito contains anticoagulant to prevent coagulation of blood while feeding and a local sedative anophilin. 

Schizogony: Once inside the human body by the bite of an infected Anopheles, Plasmodium multiples by asexual reproduction called Schizogony. It consists of two sub - phases.

• Exoerythrocytic or Hepatic schizogony    
• Erythcytic schizogony.

Exoerythrocytic or Hepatic Schizogony: It occurs in the liver cells of man. Within half an hour of inoculation, sporozoite enter the liver cells hepatocytes from blood stream and start liver schizogony or hepatic sclizogeny. Here they change into feeding stage and become spherical and are called cryptozoits. Inside the live cells, each sporozoite grows and forms a large, roughly rounded structure, the Schizont or Meroni. It undergoes multiple fission with its nucleus undergoing repeated divisions forming numerous nuclei, each gathering a bit of cytoplasm around it. This results in the formation of about 800 - 1000 cryptomerozoits in a schizont. With the rupture of live cells and schizont, cyptomerozoits are liberated into liver sinusoids. 


The eryptomerozoits enter the new liver cells to, start a new cycle of hepatic schizogony, called exoerythrocytie schiogzony. They convert into feeding metacryptoziots, each of which divides to produce either 64 large Macro - metacryptomeroziotes or 800 - 1000 micro metaeryptomerozoites. The marco - metaeryptomerozoites invade the fresh liver cells to repeat the exoerythrocytie cycle. The micro - metacryptomerozoites enter the blood stream and enter RBCs to start erythocytic sehizogony.
Erythrocytic Schizogony: In this sub - stages micro - metacrytomerozoits enter the RBCs (erythrocytes). Inside the RBCs they change into rounded disc-like trophozoites. They feed on the protein part of haemogloin and some cytoplasm and grow. The nuclei of trophozoites are pushed to one side forming a bulge and the cytoplasm form a thin layer around it. This stage is called signet-ring stage, because of the ring - like appearance of the trophozoit.

Soon vacuale disappears and the each trophozoit becomes amoeboid. It feeds upon cytoplasm of RBC and grows in size. At this stage, a toxic substance Haemozoin is produced by parasites by the digestion of hemoglobin of the host RBCs. When released in host blood due to rupture of the exhausted RBCs, haemozoin granules cause chill, body pain and malarial fever.

The trophozoites now fill almost the entire RBC and is called Schizont. Its nucleus divides by mitosis into 6 - 24 daughter nuclei. The cytoplasm surrounds each nucleus to produce 6 - 24 merozoits or Schizozoites. Now, the exhausted RBCs rupture liberating merozoites and haemozoin granules in the blood. The liberated merozoits enter new RBCs to start erythrocyte cycles afresh. The ghost RBCs (ruptured RBCs) are eliminated by spleen.

Question 3. 
Describe the Gamagon and asexual phase of malaria parasite.
Answer:
Gamogorty (Formation of Gametocytes): After repetition of a few cycles of erythrocytic schizogony, some of merozoites in the RBCs grow into Gametocyte or gamonts. These are of two types:

• Smaller male Microgametocytes with large central nucleus and
• Large female Macrogametes with reserve food and ecentric smaller nucleus.

Further growth of gametocytes can occur only in the stomach of female Anopheles mosquito because they can survive only at a temperature of about 25°C. If they fail to enter the mosquito within 48 - 72 hours, the gametocyts degenerate in man’s body. This gamogony is completed partly in man and partly in mosquito.

Question 4. 
Give a brief discription of Amoebic dysentery on th following heads:
(i) Pathogen
(ii) infection 
(iii) Transmission
(iv) Treatment.
Answer:
(i) Pathogen: Amoebiasis is cause by the infection of a protozoan parasite, Entamoeba histolytica. This parasite inhabits the anterior part (colon) of large intestine of man. Russian scientist, Losch discovered this parasite in 1875.

(ii) Infection: Entamoeba histolytica infests the upper part of the colon inside the intestine, it feeds on bacteria etc. and causes frequent diarrhoea and constipation. It invades intestinal wall, destroy mucosa and feeds upon RBCs, tissues debris and bacteria. It causes ulcers. The ulcers bust releasing blood and mucus which comes out with stool, causing acute amoebic dysentery.

(iii) Mode of Transmission (Epidemiology): The disease spreads directly through contaminated food and water and raw vegetables that have cysts of the parasite. Housefly and cockroach act as passive vectors (carriers) and carry the cysts of the parasite from the faeces, of their patients to food, water, and green vegetables. 

(iv) Treatment: Adult worms can be removed by administering a mixture of chenopodium oil and tetrachloro ethylene or hexylresarcinal crystals in gelatin capsule. Mebendazole, and Albendazole etc. are also given. 

Question 5. 
Write preventive measures against infections (communicable diseases).
Answer:
Preventive measures are precautionary steps taken to check the transmission of communicable or infectious diseases. These measures are taken at two levels: Personal hygiene and public hygiene.
Personal Hygiene: Personal hygiene can be taken by:

1. Maintaining personal cleanliness such as brushing teeth in morning and evening, washing hand before every breakfast or meal, taking bath daily.
2. Maintaining domestic hygiene by proper washing of vegetables, fruits and keeping food covered to keep away flies and making house mosquitoes and flies free.
3. Proper cleanliness and neatness of house and other usable things.
4. Taking balanced diet and avoiding malnutrition or starvation or overeating.
5. Avoiding use of alcohol, tobacco and other narcotics.
6. Sustained regular exercise that improve blood circulation to the muscles, increase stroke.

Public Hygiene: It can be improved by sanitation and public health measures.

1. Proper sanitation of public places such as parks, cinema halls, school, offices and hospitals should be taken care of. 
2. Proper disposal of waste and excreta. Garbage containers should be properly covered and garbage is not be allowed to litter on the streets or garbage collection sites.
3. Standard practices of hygiene at public catering. Eating at places such as road - side dhabas and rehris should be checked for cleanliness.
4. No stagnation of water around residential areas and drain should be covered to reduce chances of breeding of flies and mosquitoes.
5. Periodic cleaning and disinfection of water reservoir, ponds, cesspools, and tanks.
6. Insecticides should be sprayed in residential areas of regular intervals to reduce the number of mosquitoes.
7. People should be vaccinated against various infections such as cholera, typhoid, tuberculosis, whooping cough and other diseases.
8. Breeding places of disease carrying insects should be destroyed and adult vector killed by spraying insecticides.

Question 6. 
From which plant is cocoa alkaloid or cocaine obtained? What are its effect on the human body? Write the chemical structure of morphine.
Answer:
Cocoa alkaloid or cocaine in obtained from the young leaves and twigs of a shrub Erythroxylan coca found in South Ameria.
Effect on Human body:

1. Cocain is a CNS stimulant.
2. It increases mental alertness and physical strength.
3. I gives a delayed feeling.
4. It reduces sleep and appetite.
5. It addiction ultimately leads to irritational behaviour, sweating, dilation of pupils, flushed face, blurred vision and faster heart beat.

Question 7. 
Describe AIDS disease on the basis following point:
(i) Name of pathogen
(ii) Test for confirmation of disease
(iii) Main symptoms of disease
(iv) Ways of prevention
(v) Diagram of replication of retrovirus.
Answer:
(i) Human Immuno - deficieny virus (HIV) caused AIDS in human beings.

(ii) Symptoms of disease: At early stage an infected person might appear to be in good health, and may just show symptoms of ‘the flu’ i.e. simple fever, cough etc. After five to 10 years, a lot of chronic disorder develop that fare shadow AIDS emergence.

Typically, they include chronic diarrhoea, chronic weight loss, fever, many enlarged lymph nodes, short breath, fatigue, bed drenching night sweats, lethargy, pharyngitis, nausea headache etc. These may be signs of AIDS. Among others are yeast infection of mouth, vagina, oesophagus and elsewhere, and of pneumonia caused by Pneumocystis carini. Such persons show opportunistic infections i.e. they are infected by bacteria, other viruses, protozoans and fungi etc., to which a person with normal immune system resists. 

(iii) Way of transmission: AIDS is not contagious disease. It does not spread through contact, caring of infected persons, sharing meals, kissing, mosquito bites, handshake, bite of insect, etc. But AIDS can transmitted in following ways:

1. Sexual Intercourse: Unprotected sexual intercourse with an infected partner, (if there is tissue injury to permit blood contact).
2. Sharing Needles: Use of contaminated needles and syringes to inject drugs or vaccines.
3. Sharing Utensils: Use of contaminated razors for shaving.
4. Transfusion of Blood and blood Products: Transfusion of HIV contaminated blood can infect the recipient.
5. Mother to Child: A woman infacted with HIV may spread the disease through breast feeding.
6. Use of contaminated needles for boring pinnae.
7. Organ Transplant: The organs of infected person spread HIV to recipient through organ transplant.
8. Perturition from mother to baby due to rupturing of blood vessels.

(iv) Diagram of replication of Retrovirus: 

Question 8. 
Describe Typhoid disease on the basis of following points:
(i) Name of pathogen
(ii) Test for confirmation of disease
(iii) Way of infection
(iv) Main symptoms of disease
(v) Diagram showing structure of an antibody molecule.
Answer:
(i) Pathogen: Salmonella typhi.
(ii) Test for confirmation of disease: WIDAL test
(iii) Ways of infection: The bacteria spread from the digestive tract to the bloodstream (causing bacteremia) and may infect distant organs such as the following:

1. Liver, spleen, and gallbladder
2. Lungs (causing pneumonia)
3. Joints (causing infectious arthritis)
4. Kidneys (causing glomerulonephritis)
5. Heart valves (causing endocarditis)
6. Genital tract
7. The tissues covering the brain and spinal cord (causing meningitis)
8. Bone (causing osteomyelitis)

These infections develop mainly when people are not treated or when treatment is delayed.
(iv) Main symptoms: Main symptoms of typhoid are:

• Common symptom of typhoid is high temperature about 103° - 104° F. Typhoid fever rises to the maximum in the afternoon. In first week, it increases with each day. Fever remains high in second week. But in third and fourth week, it gradually decreases.
• Sever body pain, headache, and stomach pain.
• Loss of appetite, constipation and inflammation in ileum and colon.
• Extreme weakness, coated tongue, liver and spleen become enlarged.
• In serves cases intestinal perforation and death may occur.

(v) Structure of antibody Molecule: 
 

Question 9. 
(a) Differentiate between active and passive immunity.
(b) Comment on the role of vaccination and immunization in keeping human population healthy.
Answer:
(a) Difference between active and passive Immunity: 

Active Immunity	Passive Immunity
1. It is slow and provide relief only after long period.	1. It provides immediate relief.
2. It is long lasting.	2. It is short lived.
3. It has no side effect.	3. It may cause reaction.
4. It is developed by an individual's own cells in response to an infection or a vaccine.	4. It is development when ready made antibodies are inoculated from outside.

(b) The process of introducing a vaccine in the body to develop immunity against a particular disease or pathogen is called Vaccination or Immunisation. The principle of vaccination is based on the property of ‘memory’ of the immune system. Immunity develops due to formation of memory cells by the immune system. The vaccine can be introduced in the body mostly by injection and sometimes orally, e.g. polio drops. Vaccination provides immunity without infection through the introduction of weak or killed antigenic pathogen and its toxoid into a healthy person. When a vaccinated person is infected by a pathogen, the existing memory, T or B - cells recognise the antigen and induce a massive formation of T - cells and antibodies for eliminating the invader.

Question 10. 
Under polio prevention programme, infants in India were given polio vaccines on a large scale at regular intervals to eradicate polio from the country.
(i) what is vaccine? Explain, how does it import immunity to the child against the disease.
(ii) With the help of one example each differentiate between active and passive immunity.
Answer:
(i) Vaccine is a preparation of inactivated or weakened pathogen of polio virus protein that is injected into a person to provide protection against disease. During vaccination for a particular disease, an antigen or antigenic protein or weak pathogen which is on inactive form is introduced into the body to induce mild immune response. The vaccine generate antibodies that neutralises the toxin/ pathogen and produce memory, B - lymphocytes (B - cells) or T - lymphocytes (T - cells) which recoginise the pathogen in the subsequent encounters and produce antibodies.

(ii) For difference between active and passive immunity:

Active Immunity	Passive Immunity
1. It is slow and provide relief only after long period.	1. It provides immediate relief.
2. It is long lasting.	2. It is short lived.
3. It has no side effect.	3. It may cause reaction.
4. It is developed by an individual's own cells in response to an infection or a vaccine.	4. It is development when ready made antibodies are inoculated from outside.