Haryana Board (HBSE) Class 12 Biology Half Yearly Question Paper 2024 PDF Download. HBSE Class 12 Biology Half Yearly Question Paper 2024. Haryana Board Class 12 Biology Half Yearly Exam 2024. HBSE Class 12th Biology Half Yearly Paper 2024 Answer. Haryana Board Class 12 Half Yearly Paper PDF Download. Haryana Board Class 12 Biology Half Yearly Paper 2024 Solution. हरियाणा बोर्ड कक्षा 12 जीव विज्ञान अर्धवार्षिक पेपर 2024.
HBSE Class 12 Biology Half Yearly Question Paper 2024 Answer Key
Instructions :
• All questions are compulsory.
• Questions (1-9) carry 1 mark each.
• Questions (10-12) carry 2 marks each.
• Questions (13-14) carry 3 marks each.
• Question (15) case study, carry 4 marks.
• Questions (16-17) carry 5 marks each.
1. Human chromosomes with highest and least number of genes are :
(a) Chromosome 21 and Y
(b) Chromosome 1 and X
(c) Chromosome 1 and Y
(d) Chromosome X and Y
Answer – (c) Chromosome 1 and Y
2. Which of the following is a recessive trait for a character chosen by Mendel in garden pea?
(a) Violet flower colour
(b) Yellow pod colour
(c) Axial flower position
(d) Tall stem height
Answer – (b) Yellow pod colour
3. Which of the following is a false fruit :
(a) Banana
(b) Orange
(c) Apple
(d) Mango
Answer – (c) Apple
4. AIDS is caused by HIV. HIV does not spread by which of the following mean :
(a) Transfusion of contaminated blood.
(b) Sharing of infected needles.
(c) Shaking hands with an infected person.
(d) Sexual contact with an infected person.
Answer – (c) Shaking hands with an infected person.
5. Organisms capable of maintaining constant body temperature are …………
Answer – Homeothermal
6. Relaxin hormone is secreted by ……………
Answer – placenta
7. What is present in the middle piece of sperm?
Answer – Mitochondria
8. A couple has two daughters. What is the probability that the third child will also be a female?
Answer – 50%
9. Assertion (A) : Cross of F1 individual with recessive homozygous parent is test cross.
Reason (R) : No recessive individuals are obtained in the monohybrid test cross progeny.
Answer – Assertion is true but Reason is false.
10. Type of chromosomes present in male and female.
Answer – Male (XY) and Female (XX)
11. What is triple fusion? Name the nuclei involved in it.
Answer – Fusion of two polar nuclei and one male gamete is called triple fusion. It occurs in the embryo sac.
12. Wings of a bird and wings of butterfly are either analogous or homologous organ? Also tell the kind of evolution they represent.
Answer – Wings of a bird and wings of butterfly are analogous organs as their origin is not the same but they perform similar functions.
13. How can STDs be prevented?
Answer – Sexually transmitted diseases (STDs) get transferred from one individual to the other through sexual contact. STDs can be prevented by the use of contraceptives, such as condoms, etc. while intercourse, can prevent the transfer of these diseases. Sex with unknown or multiple partners should be avoided as they may have such diseases. Regular medical checkup to ensure good health is necessary.
14. What is apomixis and what is its importance?
Answer – Apomixis is the mechanism of seed production without involving the process of meiosis and syngamy. It plays an important role in hybrid seed production. The method of producing hybrid seeds by cultivation is very expensive for farmers. Also, by sowing hybrid seeds, it is difficult to maintain hybrid characters as characters segregate during meiosis. Apomixis prevents the loss of specific characters in the hybrid. Also, it is a cost-effective method for producing seeds.
15. CASE STUDY : A group of teenagers was involved in drug abuse. They used syringes and needles to inject drugs. They indulged in this habit when they became adults. Administration of drugs through needles became a piece of cake for them. Raj was the most active drug abuser amongst them and use to take drugs in high profile parties. In a span of time he started losing weight and suffered Persistent Diarrhoea. He developed constant low grade fever and used to catch opportunistic infection. When he consulted a doctor he got himself tested for HIV in his blood and finally diagnosed with AIDS.
Questions :
(a) What is the cause of Raj’s weight loss?
Answer – The cause of Raj’s weight loss is that he is suffering from AIDS.
(b) Is HIV a virus or bacteria?
Answer – HIV is a virus.
(c) Write the cause of AIDS.
Answer – The cause of AIDS are unprotected sex, due to infected syringes, from suffering mother to foetus, sex with multiple partners.
(d) Write a full form of AIDS.
Answer – Acquired Immuno Deficiency Syndrome.
16. Which Alkaloid is found in tobacco? What is its effect on human body?
Answer – Tabacco contains an alkaloid called nicotine. Nicotine is a stimulant that affects the central nervous system by increasing heart rate, blood pressure, and adrenaline levels. It is highly addictive and can lead to dependence and withdrawal symptoms when not consumed regularly. In addition to its addictive properties, nicotine is also known to have negative effects on the cardiovascular system and can contribute to the development of certain diseases such as heart disease and cancer.
17. Describe the structure of human sperm with the help of labelled diagram.
Answer – The sperm is the male gamete produced in the testes of the male reproductive system. It consists of three parts – head, middle piece and the tail. The sperm head is elongated and formed by the condensation of the nucleus. The anterior portion has a cap-like structure called acrosome. It contains hyaluronidase, an enzyme that helps the sperm to enter the ovum during fertilization. A short neck connects the head and middle piece which comprises that centrioles. The middle piece contains the mitochondria which provides energy for the movement of the tail. It brings about sperm motility which is essential for fertilization.
