Q4 ANSWER IN DETAIL AMONG ANY ONE.- 4M 1. Sketch a Dihybrid cross and explain it . 2. What is meant by chromosome? Explain its types. 3. Describe the structure of DNA molecule.
Answers
Answer:
Explanation:
A dihybrid cross is a breeding experiment between two organisms which are identical hybrids for two traits. In other words, a dihybrid cross is a cross between two organisms, with both being heterozygous for two different traits. The individuals in this type of trait are homozygous for a specific trait.
A chromosome is an organized package of DNA found in the nucleus of the cell. Different organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes--22 pairs of numbered chromosomes, called autosomes, and one pair of sex chromosomes, X and Y.
There are four types of chromosomes-
- metacentric
- sub-metacentric
- acrocentric
- telocentric chromosomes.
The DNA molecule consists of two strands that wind around one another to form a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases--adenine (A), cytosine (C), guanine (G), and thymine (T).
