Question

There are three varieties of banana.

Variety A:

Number of chromosomes in a leaf cell = 22

Growth rate of fruit = 2.9

Breaking strength of leaf = 10.8

Variety B:

Number of chromosomes in a leaf cell = 33

Growth rate of fruit = 6.9

Breaking strength of leaf = 9.4

Variety C:

Number of chromosomes in a leaf cell = 44

Growth rate of fruit = 7.2

Breaking strength of leaf = 7.8

a) How many chromosomes are there in a male gamete from variety C?

b) Explain why variety B cannot produce fertile gametes?

Answer 1

a) 22

The leaf cells of a plant are diploid that is they have 2 sets of chromosomes while gametes are haploid i.e. they have only 1 set of chromosomes. In variety C there are 44 chromosomes (22+22) so the gamete will have 22 chromosome that is only one set.

b) Variety B has the odd number of chromosomes in their plant cell which usually happens due to ploidy i.e. addition of an extra set of chromosome. They are usually fertile because the cell with an odd set of the chromosome when they go under meiosis to form gametes they chromosomes will not be able to pair up correctly.