Zoology: Solved Previous Year Question Paper for NCERT/ CBSE  Class 12th Zoology Paper code (HSEIIRKO–1) 

Zoology: Solved Previous Year Question Paper for NCERT/ CBSE  Class 12th Zoology Paper code (HSEIIRKO– 1) 

(Long Answer Type Questions) 

Question: Explain the terms 

(i) Sickle cell anaemia 

(ii) Alkaptonuria. 

Ans: (i) Sickle cell anaemia is a genetic condition where the red blood cells develop aberrant shapes. It can lead to problems like anaemia, discomfort, organ damage, and stroke. The gene that produces haemoglobin, the oxygen-carrying molecule in red blood cells, has a mutation that causes the disease.

(ii) The inability of the body to break down specific proteins is known as Alkaptonuria, a rare inherited metabolic condition. As a result, homogentisic acid builds up in the body, which can result in kidney stones, arthritis, heart issues, and blackening of the skin.

Question: Explain in the brief modern synthetic theory of evolution. 

Ans: To explain how populations evolve, Charles Darwin’s theory of natural selection and Gregor Mendel’s principles of heredity are combined in the modern synthesis theory of evolution, commonly referred to as the Neo-Darwinian theory. According to the most recent theory, natural selection uses genetic diversity to develop adaptations that boost an organism’s chances of survival and reproduction. Genetic variation arises from gene mutations, the idea says. The idea also suggests that populations are always changing, with new genetic variations appearing and evolving into new species as they adapt to their surroundings.

Question: Define Spermatogenesis. With the help of a graphic sketch explain the processes involved in spermatogenesis. 

Ans: The process by which sperm cells are created from spermatogonial stem cells is known as spermatogenesis (precursor cells). It involves a series of processes, including cell differentiation, meiotic divisions, and mitotic divisions, and takes place in the seminiferous tubules of the testes.


1: Spermatogenesis-related procedures. Primary spermatocytes are created when the spermatogonial stem cells (1) undergo mitosis

(2). The secondary spermatocytes are created by meiotic divisions of the main spermatocytes

(3). After then, the secondary spermatocytes divide once again to form spermatids

(4). The spermatids eventually mature to become spermatozoa

(5). Once in the epididymis, the spermatozoa acquire motility and the capacity to fertilise an oocyte.

Question: What do you mean by ‘Contraception’? Write down the preventive measure for sexually transmitted diseases. 

Ans: The use of various techniques of contraception is done to avoid becoming pregnant. Pills for birth control, condoms, IUDs, and female sterilisation are typical contraceptive techniques. The following are some preventative steps for sexually transmitted diseases:

1. Utilizing condoms each time you have sex,

2. Abstaining from sexual activity,

3. Getting frequent STD examinations is recommended.

4. Receiving an STD vaccination.

5. Reducing the number of partners for sexual activity

6. Engaging in mutual monogamy with a partner who has had their STDs tested

7. Abstaining from alcohol and illicit substances when having sex.

(Short Answer Type Questions) 

Question: Write down the symptoms of Malaria. 

Ans: 1. Fever 2. Cold 3. Perspiring 4. Migraine 4. Vomiting 5. Muscle ache 7. Tiredness 8. Diarrhoea 9. Anaemia

Question: What do you mean by Vaccine Production and its uses? 

Ans: The process of creating vaccines to prevent disease is known as vaccine production. A virus or bacteria is used to make vaccines by weakening or destroying it so that it can no longer cause disease but still trigger the body to manufacture antibodies that will guard against the disease. Then, individuals receive the vaccines via injection, nasal spray, oral drops, or other means. Vaccines are used to stop the spread of infectious diseases and have assisted in lowering their mortality toll. They are a crucial component of public health because they shield both individuals and communities from illness.

Question: Write a short note on assisted reproductive technologies. 

Ans: A range of techniques known as assisted reproductive technologies (ART) are used to treat infertility and other disorders of the reproductive system. These technologies employ medical procedures to increase the likelihood of pregnancy and birth. This covers donor egg and sperm donation, intrauterine insemination (IUI), gamete intrafallopian transfer (GIFT), and zygote intrafallopian transfer (ZIFT). Couples who are unable to conceive naturally can get pregnant and have a healthy kid by using these technologies.

Question: Write down how the inheritance of haemophilia takes place in man. 

Ans: Hemophilia in men is inherited in an X-linked recessive pattern, which implies that the X chromosome contains the gene that causes the condition. Because they only have one X chromosome, males are more likely to be affected by the condition than females, who have two X chromosomes and can carry the defective gene without necessarily expressing it. The male offspring of a mother who possesses the gene will typically also be carriers and develop haemophilia if they have sons. (Very Short Answer Type Questions) 

Question: Write a note on silkworms as an insect for human welfare.

Ans: Humans have been producing silk using the silkworm, an insect, for thousands of years. A luxurious material, silk is used to create a variety of products, including clothing, bedding, and drapes. The silkworm is a crucial insect for human prosperity as it gives silk producers a vital source of revenue and aids in the creation of jobs in the textile sector. Since the silkworm is a crucial link in the food chain, it also contributes to the preservation of biodiversity. Numerous birds and other animals consume silkworm larvae, providing a natural food source. The silkworm is a significant pest control tool since it also produces a pesticide that is naturally occurring. The silkworm is a beneficial insect that plays a significant role in human welfare.

Question: What is Human Insulin? Write down its uses.

Ans: Synthetic human insulin is created in a lab using recombinant DNA technology. It is used to treat diabetic patients and is identical to the insulin made by the human body. It assists in controlling blood sugar levels, hence reducing the risk of diabetes-related problems like heart disease and stroke. Human insulin can be injected, breathed, or administered through a pump. Both type 1 and type 2 diabetes are managed with it.

Question: What do you mean by Parturition? 

Ans: When a baby is delivered after a mother has carried it inside her for nine months, the process is known as parturition. It is also known as labour and delivery.

Question: What is Hemophilia? Why is it called Bleeder’s disease?

Ans: Hemophilia is a rare, genetic bleeding illness where the blood does not clot properly. It results from a shortage or absence of specific clotting factors in the blood. Because haemophiliacs frequently bleed for longer periods than average following an injury or surgery, the disease is commonly referred to as “bleeder’s disease.”

 (Objective Type Questions/M.C.Q.) 

Ans: Evolution was the link between man and other primates. 

Question: (i) Dealcoholism is the process of overcoming drinking, whether true/false

Ans: True.

Question: (i) Expand the term LSD. 

Ans: LSD stands for Lysergic Acid Diethylamide, a potent psychedelic drug known for its psychological effects.

(ii) Treponema pallidium is a 

 (a) Bacterial agent 

(b) Viral agent 

(c) Protozoal agent 

(d) Fungal agent 

Answer: (a) Bacterial agent

Question: (iii) Expand the term PKU. 

Ans: Phenylketonuria (PKU)

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