Class 12 biology chapter 10 Human Health and Diseases Solutions

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Q. 1 Multiple Choice Questions
1. Which of the following is NOT caused by unsterilized needles?
 a. Elephantiasis
 b. AIDS
 c. Malaria
 d. Hepatitis B

2. Opium derivative is ..............
a. Codeine
b. Caffeine
c. Heroin
d. Psilocybin

3. The stimulant present in tea is .............
a. tannin
b. cocaine
c. caffeine
d. crack

4. Which of the following is caused by 
 a. Liver cirrhosis
 b. Pulmonary tuberculosis
 c. Emphysema
 d. Malaria

5. An antibody is ...............
 a. molecule that binds specifically an 
b. WBC which invades bacteria
 c. secretion of mammalian RBC
 d. cellular component of blood

6. The antiviral proteins released by a 
virus-infected cell are called ............ 
a. histamines
b. interferons
c. pyrogens
d. allergens

7. Both B-cells and T-cells are derived 
from .................... 
 a. lymph nodes
 b. thymus glands
 c. liver
 d. stem cells in bone marrow

8. Which of the following diseases can be 
contracted by droplet infection?
a. Malaria
b. Chicken pox
c. Pneumonia
d. Rabies

9. Confirmatory test used for detecting 
HIV infection is .................
b. Western blot
c. Widal test
d. Eastern blot

10. Elephantiasis is caused by ............ 
a. W. bancrofti
b. P. vivax
c. Bedbug
d. Elephant

11. Innate immunity is provided by ...........
 a. phagocytes
 b. antibody
 c. T- Lymphocytes
 d. B- Lymphocytes

Q. 2 Very Short Answer Questions 
1. What is the source of cocaine?
Answer :  Cocaine is a powerfully addictive stimulant drug. ingested coca leaves (Erythroxylon coca), the source of cocaine.

2. Name one disease caused by smoking?
Answer : Lung diseases caused by smoking include COPD, which includes emphysema and chronic bronchitis. Cigarette smoking causes most cases of lung cancer.

3. Which cells stimulate B-cells to form 
Answer : When na├»ve or memory B cells are activated by antigen (and helper T cells—not shown), they proliferate and differentiate into effector cells. The effector cells produce and secrete antibodies.

4. What does the abbreviation AIDS stand for?
Answer : AIDS stands for Acquired Immune Deficiency Syndrome.

5. Name the causative agent of typhoid 
Answer : salmonella typhi.

6. What is Rh factor?
Answer : Rhesus (Rh) factor is an inherited protein found on the surface of red blood cells. If your blood has the protein, you're Rh positive. If your blood lacks the protein, you're Rh negative.

7. What is schizont?
Answer : A schizont is a malaria parasite which has matured and contains many merozoites, which are the parasite stage that infects red blood cells.

8. Name the addicting component found in tobacco.
Answer : Nicotine

9. Name the pathogen causing Malaria.
Answer : The most serious forms of the disease are caused by Plasmodium falciparum and Plasmodium vivax, but other related species (Plasmodium ovale and Plasmodium malariae) can also infect humans.

10. Name the vector of Filariasis.
Answer : A wide range of mosquitoes can transmit the parasite, depending on the geographic area. In Africa, the most common vector is Anopheles and in the Americas, it is Culex quinquefasciatus. Aedes and Mansonia can transmit the infection in the Pacific and in Asia.

11. Give the name of the causative agent of ringworm.
Answer : Contrary to its name, the causative agents of ringworm are not worms but are several types of fungus called dermatophytes.

12. Define health.
Answer : Health is a state of physical, mental and social well-being in which disease and infirmity are absent.

Q. 3 Short Answer Questions: 
1. What are acquired diseases?
Answer : Acquired diseases are a primary disease that begins after birth at some point during one's lifetime. It may also be a congenital disease that is acquired from the mother during birth.

2. Differentiate between antigen and 
Answer : Antigens are molecules capable of stimulating an immune response. Each antigen has distinct surface features, or epitopes, resulting in specific responses. Antibodies (immunoglobins) are Y-shaped proteins produced by B cells of the immune system in response to exposure to antigens.

3. Name the infective stage of Plasmodium. Give any two symptoms of malaria.
Answer : The human-infective stage are sporozoites from the salivary gland of a mosquito. The sporozoites grow and multiply in the liver to become merozoites. These merozoites invade the erythrocytes (RBCs) to form trophozoites, schizonts and gametocytes, during which the symptoms of malaria are produced.

4. Explain the mode of infection and cause of elephantiasis.
Answer : Elephantiasis refers to a parasitic infection that causes extreme swelling in the arms and legs. The disease is caused by the filarial worm, which is transmitted form human to human via the female mosquito when it takes a blood meal.

5. Why is smoking a bad habit?
Answer : Smoking is a hard habit to break because tobacco contains the very addictive chemical nicotine. As with heroin or other addictive drugs, the body and mind quickly get used to the nicotine in cigarettes. Soon, a person needs to have it just to feel normal.

6. What do the abbreviations AIIMS and 
CMIS denote?
Answer : AIIMS : All India Institute of Medical Sciences

CMIS : Common Management Information Service Computing

7. What is a carcinogen? Name one chemical carcinogen with its target tissue.
Answer : These include tobacco and tobacco smoke, pesticides used to control bugs, asbestos, radon, and arsenic.

8. Distinguish between active immunity 
and passive immunity.
Answer : Active immunity and passive immunity are two types of adaptive immunity. A prominent difference between active and passive immunity is that active immunity is developed due to the production of antibodies in one's own body, while passive immunity is developed by antibodies that are produced outside.

Q. 4 Short Answer Questions 
1. Differentiate between B-cells and 
Answer : Both T cells and B cells are produced in the bone marrow. The T cells migrate to the thymus for maturation. ... The main difference between T cells and B cells is that T cells can only recognize viral antigens outside the infected cells whereas B cells can recognize the surface antigens of bacteria and viruses.

2. What are the symptoms of malaria? 
How does malaria spread?
Answer : Malaria is a life-threatening disease. It’s typically transmitted through the bite of an infected Anopheles mosquito. Infected mosquitoes carry the Plasmodium parasite. When this mosquito bites you, the parasite is released into your bloodstream. Once the parasites are inside your body, they travel to the liver, where they mature. After several days, the mature parasites enter the bloodstream and begin to infect red blood cells.

Within 48 to 72 hours, the parasites inside the red blood cells multiply, causing the infected cells to burst open.

The parasites continue to infect red blood cells, resulting in symptoms that occur in cycles that last two to three days at a time.

3. Write a short note on AIDS.
Answer : AIDS (Acquired Immune Deficiency Syndrome) is the final and most serious stage of HIV disease, which causes severe damage to the immune system.

The Centers for Disease Control has defined AIDS as beginning when a person with HIV infection has a CD4 cell (also called "t-cell", a type of immune cell) count below 200. It is also defined by numerous opportunistic infections and cancers that occur in the presence of HIV infection.

4. Give the symptoms of cancer.
Answer : symptoms of cancer people often overlook include:

  1. Unexplained weight loss.
  2. Fever of unknown origin.
  3. Night sweats.
  4. New or unexplained pain.
  5. Persistent heartburn.
  6. Mouth or tongue sores that don't heal.
  7. Bloating.
  8. Irregular bowel patterns.

5. Write a note on antigens on blood cells.
Answer : Blood is classified into different groups according to the presence or absence of molecules called antigens on the surface of every red blood cell in a person's body. Antigens determine blood type and can either be proteins or complexes of sugar molecules (polysaccharides).

6. Write a note on antigens-antibody 
Answer : An immune complex, sometimes called an antigen-antibody complex, is a molecule formed from the binding of multiple antigens to antibodies. The bound antigen and antibody act as a unitary object, effectively an antigen of its own with a specific epitope.

7. What are the various public health 
measures, which you would suggest as 
safeguard against infectious diseases?
Answer : Maintenance of personal and public hygiene is very important as safeguard against infectious diseases.

Measures for personal hygiene include:
Keeping the body clean
Consumption of clean drinking water, food, vegetables, fruits, etc.

Measures for public hygiene includes:
Proper disposal of waste and excreta
Periodic cleaning and disinfection of water reservoirs pools, cesspools and tanks
Observing standard practices of hygiene in public catering
In cases of air-borne diseases such as pneumonia and common cold, close contact with the infected persons or their belongings should be avoided.
For diseases transmitted through insect vectors, the most important measure is to control or eliminate the vectors and their breeding places.

8. How does the transmission of each of 
the following diseases take place?
a. Amoebiasis
Answer :  Amoebiasis is usually transmitted by the fecal-oral route, but it can also be transmitted indirectly through contact with dirty hands or objects as well as by anal-oral contact. Infection is spread through ingestion of the cyst form of the parasite, a semi-dormant and hardy structure found in feces.

b. Malaria
Malaria is not contagious and you can't catch it from physical contact with someone who has it. The malaria parasite is not in an infected person's saliva and it is not passed on from one person to another. The only way you can catch malaria from a person is through blood transfusions or organ transplants.

c. Ascariasis
Answer :  Mode of transmission of Ascaris
Transmission occurs when eggs are swallowed from soil contaminated with human faeces or consumed with produce contaminated with soil containing infective eggs. Transmission does not occur from direct person-to-person contact or from fresh faeces.

d. Pneumonia
Answer :
Pneumonia can be spread in a number of ways. The viruses and bacteria that are commonly found in a child's nose or throat, can infect the lungs if they are inhaled. They may also spread via air-borne droplets from a cough or sneeze.

9. What measure would you take to prevent water-borne diseases?
Answer : Access to safe drinking water is the most significant step to prevent the outbreak of water-borne diseases. Water that is used for cooking or drinking needs to be disinfected on a regular basis.

10. Write a short note on typhoid
Answer : Typhoid is a bacterial infection that can lead to a high fever, diarrhea, and vomiting. It can be fatal. It is caused by the bacteria Salmonella typhi. The infection is often passed on through contaminated food and drinking water, and it is more prevalent in places where handwashing is less frequent.

Q.5 Match the following
 Answer :
a - v
b - iv
c - i
d - ii
e - iii

Q. 6 Long Answer Questions

1. Describe the structure of antibody.
Answer : Antibodies are glycoproteins which are highly specific to specific antigens. They are also known as Immunoglobulins (Igs),
produced in response to antigenic stimulation. Antibodies are produced by plasma cells which in turn are formed by B–lymphocytes. The mature plasma cells produce antibodies at an extremely rapid rate i.e. about 2000 molecules per second.

Antibody is a ‘Y’ shaped molecule. Each
immunoglobulin molecule is made up of four polypeptide chains. There are two heavy or H-chains and two light or L-chains. The four polypeptide chains are held together by disulfide bonds (-s-s-) to form a ‘Y’ shaped structure. The region holding together arms and stem of antibody, is termed as hinge. Each
chain of the antibody includes two distinct
regions, the variable region and the constant region. Variable regions constitute the antigen-binding site (paratope). This part of antibody recognizes and binds to the specific antigen to form an antigen-antibody complex. Since most
antibodies carry two antigen binding sites, they are said to be bivalent.

2. Write a note on Vaccination.
Answer : Administration of vaccine (i.e. inactivated pathogen or antigenic protection of particular pathogen) to protect against a particular pathogen, is called vaccination. The body’s immune system helps to protect against pathogens that cause infection. It’s an efficient system, most of the time,. It either keeps microorganisms out or tracks them down and gets rid of them. Vaccination is a way to “teach” the immune system as to how to recognize and eliminate pathogenic organism. That way, body is always prepared if you are ever exposed.
Vaccination is an important form of
primary prevention, that can protect people from getting sick. Vaccination has allowed us to control diseases like measles, polio, tetanus and whooping cough that once threatened many lives

3. What is cancer? Differentiate between 
bening tumor and malignant tumor. 
Name the main five types of cancer.
Answer : 

Characteristics of Benign Tumors

  1. Cells tend not to spread
  2. Most grow slowly
  3. Do not invade nearby tissue
  4. Do not metastasize (spread) to other parts of the body
  5. Tend to have clear boundaries
  6. Under a pathologist's microscope, shape, chromosomes, and DNA of cells appear normal
  7. Do not secrete hormones or other substances.

Characteristics of Malignant Tumors
Cells can spread

  1. Usually grow fairly rapidly
  2. Often invade basal membrane that surrounds nearby healthy tissue
  3. Can spread via bloodstream or lymphatic system, or by sending "fingers" into nearby tissue
  4. May recur after removal, sometimes in areas other the original site
  5. Cells have abnormal chromosomes and DNA

4. Describe the different type of immunity.
Answer : Types of Acquired Immunity:
Acquired immunity is of two types Active
and Passive.

a. Active immunity:
It is the resistance developed by
individuals as a result of an antigenic stimulus. It also known as “Adaptive immunity”. Active immunity may be natural or artificial.

1. Natural Acquired Active immunity:
Immunity acquired due to infection is
called natural active immunity. It is
developed after entry of pathogens in
the body. It is long-lasting immunity. e.g.
person who has recovered from attack of  measles develops natural acquired active
immunity to measles, for the life time.

2. Artificial Acquired Active immunity:
It is the resistance induced by vaccines.
Vaccine is introduced into the body to
stimulate the formation of antibodies by
the immune system. e.g. Polio vaccine, BCG vaccine etc. such immunity may be
temporary or permanent.

b. Passive immunity:
 Passive immunity is acquired when ready-
made antibodies are received by the body cells. i.e. Body cells do not take any active part in the production of immunity. Passive immunity can be acquired either naturally or artificially.

1. Natural Acquired Passive immunity:
Before birth maternal antibodies are
transferred from mother to foetus
through placenta. After birth, antibodies
are transferred from mother to infant
through colostrum (first milk of mother)
and continue throughout the period of
breast feeding. The antibodies received
by baby from mother remain in the
body for a short time. Therefore, natural
acquired passive immunity is short lived.

2. Artificially Acquired Passive 
immunity: This immunity is developed
by injecting previously prepared
antibodies using serum from humans or
animals. For e.g. Antibodies obtained
from hyper immunised horses are
injected to humans against rabies
pathogens. It is short lived.

5. Describe the ill –effects of alcoholism on health.
The immediate adverse effects of drugs
and alcohol abuse are manifested in the form of reckless behaviour, vandalism and violence.

Excessive doses of drugs may lead to coma and death due to respiratory failure, heart failure or cerebral hemorrhage. A combination of drugs or their intake along with alcohol generally results in overdose and even deaths. The most common warning signs of drug and alcohol abuse among youth include drop in
academic performance, unexplained absence from school/college, lack of interest in personal hygiene, withdrawal, isolation, depression, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family and
friends, loss of interest in hobbies, change in sleeping and eating habits, fluctuations in weight, appetite, etc.

6. In your view, what motivates the 
youngsters to take to alcohol or drugs 
and how can this be avoided?
Answer : Youngsters generally take alcohol or drugs on the basis of the following factors.
(i) Curiosity
(ii) Pleasure
(iii) To escape from the realities of life, to overcome frustrations and depressions.
(iv) Friends pressure.
(v) Desire of excitement.
(vi) Desire to do more work.
(vii) Unhappy married life.
(vii) Monotony of daily life.

It can be avoided by the following ways.
(i) Educating and counselling the child to face problems and stresses and accept disappointments and failure as a part of life.
(ii) A child should not be pushed unduly to perform beyond his capacity.
(iii) Parents and teachers should be alert the activities of the child.
(iv) Help can be taken from highly qualified psychologists and pyschiatrists.

7. Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
Answer : Yes, friends can influence one to take drugs and alcohol. A person can take the following steps for protecting himself/herself against drug abuse:

(a) Increase your will power to stay away from alcohol and drugs. One should not experiment with alcohol for curiosity and fun.

(b) Avoid the company of friends who take drugs.

(c) Seek help from parents and peers.

(d) Take proper knowledge and counseling about drug abuse. Devote your energy in other extra-curricular activities.