Zoology: Solved Previous Year Question Paper for NCERT/ CBSE Class 12th Zoology Paper code (RKDO18 20304-X) 

Zoology: Solved Previous Year Question Paper for NCERT/ CBSE Class 12th Zoology Paper code (RKDO18 20304-X)

(Long Answer Type Questions) 

Question: What do you mean by Reproductive Health? Write down the significance of Reproductive Health in a society. 

Answer: Reproductive health is the state of physical, mental, and social well-being related to reproductive processes and functions in both men and women.

Significance of Reproductive Health in a society 

1. The significance of Reproductive Health in a society is that it is essential for people to have access to comprehensive reproductive health services and information in order to make informed decisions about their reproductive health.

2. Reproductive health is also important for reducing maternal mortality and morbidity, as well as for achieving gender equality.

3. Additionally, it is important for improving the overall health of a population and for protecting against the spread of sexually transmitted infections. Finally, access to reproductive health services is an important aspect of achieving human rights for all.

Question: Describe the sequence of events from Zygote till the implantation of human blastocyst in the Uterus. 

Answer: The sequence of events from zygote to implantation of a human blastocyst in the uterus is as follows:

1. The zygote is formed when a sperm cell and an egg cell fuse together.

2. The zygote begins to divide rapidly and forms a hollow ball of cells called a blastocyst.

3. The blastocyst implants itself into the lining of the uterus, where it will continue to grow and develop.

4. The blastocyst becomes embedded in the uterine wall and begins receiving nutrients from the mother’s blood.

5. The blastocyst continues to develop and eventually forms an embryo.

 6. The embryo then begins to grow and develop into a fetus.

7. The fetus continues to grow and develop until it is ready to be born.

Question: Explain Founder’s effect and Bottleneck effect in brief. 

Answer: The Founder’s Effect is a phenomenon which occurs when a small population of individuals migrates to a new location and the genetic composition of the original population is drastically reduced. This often results in a population with a high degree of genetic variation, since the new population is descended from a small number of individuals.

The Bottleneck Effect occurs when a population is drastically reduced in size due to environmental factors such as natural disasters, disease, or human intervention. This can result in the loss of genetic variation within the population and can lead to reduced genetic diversity. As a result, the population may become less resilient to environmental change, disease, or other conditions.

Question: What is DNA-fingerprinting? Who developed this technique? Add a short note on principle of DNA-fingerprinting. 

Answer: DNA-fingerprinting is a technique which was developed by geneticist Alec Jeffreys in the 1980s.

It is a form of genetic analysis which is used to identify a specific individual based on the comparison of their genetic material with that of another individual. The principle of DNA-fingerprinting involves extracting and analyzing a person’s DNA in order to identify unique patterns, or ‘fingerprints’, which are specific to that individual. This pattern is then compared with that of other individuals in order to determine if they are related.

Question: Explain in brief Down’s Syndrome (important)

Answer: Already discussed

 (Short Answer Type Questions) 

Question: Draw a well labelled diagram of microscopic anatomy of testis. 

Answer: [Diagram of Microscopic Anatomy of Testis]

1. Seminiferous Tubules – A network of tiny tubes that produce sperm cells.

2. Interstitial Cells – Cells that produce testosterone and other hormones.

3. Leydig Cells – Cells that produce testosterone.

4. Blood Vessels – Carry nutrients and hormones to the seminiferous tubules.

5. Lymphatic Vessels – Carry away waste products from the testes.

6. Sertoli Cells – Support cells that help to protect the sperm cells.

Question: Write a short note on color blindness in human beings. 

Answer: Color blindness, also known as color vision deficiency, is the inability to distinguish certain colors in the visible light spectrum. It affects around 8% of men and 0.5% of women, with the most common type being red-green color blindness.

Color blindness can be caused by genetic factors or acquired through injury or disease.

Symptoms include difficulty distinguishing between colors, difficulty identifying colors, and difficulty seeing color in low light or bright light.

Treatment for color blindness is not available, but people with the disorder can often find ways to adapt, such as using color-coded objects or specialized lenses.

Question: Write down the causes of Filariasis (important)

Answer: Already discussed

 (Very Short Answer Type Questions) 

Question: Define the terms Spermatogenesis and Oogenesis. 

Answer: Spermatogenesis is the process by which male germ cells (sperm) are produced from spermatogonial stem cells.

Oogenesis is the process by which female germ cells (oocytes) are produced from oogonial stem cells.

Question: What do you mean by ‘Gene therapy’ 

Answer: Gene therapy is a type of medical treatment that involves altering a person’s genetic material to treat or prevent a disease.

Question: What do you mean by Pathogens and Parasites ? 

Answer: Pathogens are microorganisms that cause disease, such as bacteria, viruses, fungi, and protozoans.

Parasites are organisms that live in or on another organism (the host) and benefit from the host without providing any benefit in return.

Question: What is Cloning? 

Answer: Cloning is the process of producing genetically identical copies of a living organism or of specific cells or DNA fragments.Cloning can also be used to create copies of organs, tissues, and cells for medical purposes.

 (Objective Type Questions/MCQ) 

Question: (1) Expand the term ZIFT and GIFT. 

Answer: ZIFT: Zygote Intrafallopian Transfer

GIFT: Gamete Intrafallopian Transfer

Question: (ii) Who amongst the following proposed the theory of origin of species by Natural Selection ? 

(a) August Weismann 

(b) Hugo de-Vries 

(c) Charles Darwin 

(d) Alfred Wallace 

Answer: (c) Charles Darwin

Question:  (iii) Alcohol is a “stimulant”. (Yes/No) 

Answer: No

Question: (iv) Less response of a drug to a specific dose with repeated use is called———– 

Answer: Tolerance.

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