Maharashtra HSC Biology Most Repeated Question 2025

1

In absence of fertilization, corpus luteum degenerates into ........

Answer: corpus albicans

2

Histones are rich in

Answer: Lysine and Arginine

3

During replication of DNA, the separated strands are prevented from recoiling by using …..

Answer: single strand binding protein

4

While playing cricket Raju faces a problem of severe pain and heaviness in the-chest. Pain spreads from neck, lower jaw, left arm and to left shoulder. From above symptoms identify disease:

Answer: Angina pectoris

5

—-----Layer is in close contact with CNS in human beings.

Answer: Dura Matter

6

Annealing step of PCR, operates at .......с.

Answer: 40-60

7

Which of the following is the only gaseous plant growth regulator?

Answer: Ethylene

8

What happens in In Hamburger's phenomenon

Answer: CI- diffuse into RBCs

9

What are vestigeal organs?

10

Distinguish between heterochromatin and euchromatin with reference to staining property and activity.

11

Differentiate between X-chromosome and Y-chromosome.

12

Draw a suitable diagram of replication of eukaryotic DNA and label any three parts.

13

Draw a neat and proportionate diagram of root hair and label mitochondria, nucleus and vacuole.

14

Distinguish between human sperm and ovum.

15

Distinguish between artery and vein.

16

What is blood pressure? add a note on factors affecting it.

17

With the help of neat, labelled diagram describe the human female reproductive system.

18

Identify chromosomal disorder caused due to non-disjunction of 21st number of chromosomes and enlist its symptoms.

19

Describe the steps of PCR.

20

Explain cardiac cycle.

21

Draw a neat diagram of the conducting system of the human heart and label AV node, Bundle of His and Purkinje fibres.

22

What is Reproductive Isolation? Describe its any two types

23

Explain homologous and analogous organs.