Zoology: Solved Previous Year Question Paper for NCERT/ CBSE Class 12th Zoology Paper code (HSEIIRKON1—-15321-A) 

Zoology: Solved Previous Year Question Paper for NCERT/ CBSE Class 12th Zoology Paper code (HSEIIRKON1—-15321-A)

(Long Answer Type Questions) 

Question: Define asexual reproduction, mention various methods of asexual reproduction. Describe any three of them. 

Answer: Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or the exchange of genetic material. Asexual reproduction occurs when a single organism produces offspring that are genetically identical to itself.

This can be accomplished through various methods, such as fragmentation, budding, vegetative propagation, and spore formation.

1. Fragmentation involves a single organism breaking into two or more separate parts, each of which is able to grow into a new organism. This form of asexual reproduction is common among many plants, such as ferns, mosses, and liverworts.

2. Budding is a form of asexual reproduction where a new organism develops from an outgrowth of the parent organism. This type of reproduction is seen in many animals, such as jellyfish and sea anemones.

3. Vegetative propagation is a form of asexual reproduction that involves the growth of a new organism from a portion of the parent organism. This type of reproduction is particularly common among plants, where new plants may grow from cuttings or from rhizomes, tubers, and bulbs.

4. Spore formation is a form of asexual reproduction that involves the production of spores. Spores are haploid

Question: Define Spermatogenesis. Explain it with diagrammatic representation. (important)

Answer: Already discussed

Question: Explain the Inheritance pattern of Haemophilia and colour blindness in human beings. 

Answer: Haemophilia and colour blindness are both inherited genetic disorders that are passed down through families.

Haemophilia is an inherited disorder in which a person has a reduced ability to form blood clots resulting in excessive bleeding. It is an X-linked recessive trait, meaning that it is passed down from a mother to her son or daughter on the X chromosome.

Colour blindness is an inherited condition in which a person’s ability to distinguish certain colours is reduced or absent. It is also an X-linked recessive trait, meaning that it is passed down from a mother to her son or daughter on the X chromosome. Since these conditions are both X-linked recessive traits, a male child will inherit the condition from his mother if she is a carrier. A female child will only inherit the condition if both her mother and father are carriers.

Question: Describe Darwin’s theory of Natural selection. 

Answer: Darwin’s theory of Natural Selection is the process by which organisms that possess heritable traits that enable them to better adapt to their environment are more likely to survive and reproduce than those that do not possess such traits. This process acts on the genetic diversity of a population, leading to the development of new species and the extinction of others.

Natural Selection is driven by four main principles: Variation, Inheritance, Overproduction, and Differential Survival & Reproduction.

Variation refers to the fact that members of a population will have different traits, which can be inherited by their offspring.

Overproduction ensures that the population will have a surplus of individuals, meaning only those with the most advantageous traits will survive and reproduce.

Differential Survival & Reproduction is the process by which the organisms with the most advantageous traits will have a higher chance of survival and reproduction than those with less advantageous traits. Over time, this process leads to the emergence of new species and the extinction of others.

 (Short Answer Type Questions) 

Question: Write a short note on ‘MTP’.

Answer: MTP (Mixed Tissue Proteins) are proteins found in multiple tissues of the body. These proteins are involved in various functions such as cell signaling, metabolism, and other cellular processes. They are also involved in the cell-to-cell communication network.

Question: Expalin the mechanism of sex determination in birds.

Answer: The mechanism of sex determination in birds is known as the ZZ/ZW system. This system is based on the presence or absence of a pair of sex chromosomes, called the Z and W chromosomes. In avian species, the female is the homogametic sex (ZZ) and the male is the heterogametic sex (ZW). At fertilization, the male gamete (sperm) will randomly contribute either a Z or a W chromosome, while the female gamete (ova) will always contribute a Z chromosome. This means that the sex of an offspring is determined by the chromosome that is contributed by the male. If the male contributes a Z chromosome, the offspring will be female (ZZ), and if the male contributes a W chromosome, the offspring will be male (ZW).

Question: What is Cancer? Explain the preventive measures of Cancer? 

Answer: Cancer is a group of diseases that cause cells in the body to grow and divide without control or order. In most cases, cancer cells can spread to other parts of the body, forming a mass of cancer cells called a tumor.

Preventive measures for cancer include:

1. Avoiding exposure to carcinogens: Avoiding exposure to carcinogens, such as tobacco smoke and radiation, can help to prevent cancer.

2. Eating a healthy diet: Eating a diet high in fruits and vegetables and low in processed and red meats can help reduce the risk of many forms of cancer.

3. Exercise regularly: Exercise can help reduce the risk of certain types of cancer, such as colon and breast cancer.

4. Maintain a healthy weight: Maintaining a healthy weight can help reduce the risk of many types of cancer.

5. Limiting alcohol: Limiting alcohol consumption can help reduce the risk of certain types of cancer.

6. Vaccination: Vaccination against certain viruses, such as HPV, can help reduce the risk of certain cancers.

7. Get screened: Getting regular screening tests for certain types of cancer, such as breast and colon cancer, can help detect cancer early, when it is most treatable.

Question: Write a short note on Genetic Enginering. 

Answer: Genetic engineering is a technology that is used to modify or alter the genetic material of an organism. It involves making changes to an organism’s DNA in order to give it new traits or characteristics. Genetic engineering is used to produce genetically modified organisms (GMOs), which can have a variety of applications in medicine, agriculture, and other areas. Genetic engineering can also be used to create new organisms with desired traits, such as disease resistance or increased crop yields.

(Very Short Answer Type Questions) 

Question: Explain in brief the term Amniocentesis. 

Answer: Amniocentesis is a medical procedure where a small sample of the amniotic fluid that surrounds a fetus in the uterus is taken and tested. It is usually performed between the 15th and 20th weeks of pregnancy. The procedure is usually done to identify potential birth defects, genetic disorders, and health problems.

Question: What is the significance of ‘Human Genome Project’ ? 

Answer: The Human Genome Project was a groundbreaking international scientific research project with the goal of mapping out the entire human genome. The project was a major breakthrough in our understanding of human genetics, providing us with valuable genetic information that can be used to improve medical treatments and identify genetic disorders.

Question: What do you mean by Alcohol abuse? important 

Answer: Alcohol abuse is a pattern of drinking that results in harm to one’s health, interpersonal relationships, or ability to work.

It can also include drinking despite negative consequences, such as loss of job or relationship, or physical or psychological harm.

Question: Write down the significance of cloning. 

Answer: 1. Cloning is a process used to create an exact genetic replica of a living organism.

2. It has a range of important implications and applications, including agricultural, medical, and therapeutic purposes.

3. In agricultural applications, cloning can help produce animals with desirable qualities, such as leaner meat or higher milk production.

4. In medical applications, cloning can be used to create tissues and organs to replace damaged or diseased ones.

 (MCQ/Objective Type Questions) 

 Question: (i) Give the full form of IVF 

Ans: IVF means In-Vitro Fertilization

Question: (ii) The cranial capacity of Homo sapians man is 1700 cc  (True/False) 

Ans: True

Question: (iii) The pair of chromosomes that are associated with sex 

determination are known as 

Ans: sex chromosomes.

Question: Who is known as the ‘Father of Immunology’ ? 

Answer: Louis Pasteur

Question: The spread of cancerous cells to distinct sites is termed as

(a) Carcinogenes 

(b) Metastasis 

(c) Benign Tumor 

(d) Maliginant neoplasm 

(Choose the correct one)

Answer: (b) Metastasis

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