Fertilisation In Plants extra

Question 1

Describe the role of each of the male nuclei in the process of Fertilsation in flowering plants

Answer 1

One haploid male gamete will fuse with a female haploid gamete creating a diploid zygote. And the fusion og the polar nuclei with the sperm nucleus gives rise to a triploid endosperm

Question 2

Give three roles of water in a plant other than for pollen tube growth.

Answer 2

Photosynthesis
Hydrolysis
Water is a transport medium

Question 3

Suggest the role of digestive enzymes in the growth of a pollen tube

Answer 3

the enzymes digest the style, the enzymes then break down the middle lamella this allows for a much easier pollen tube growth therefore reducing resistance.

Question 4

Suggest the advantages to flowering plants of increased pollen tube growth

Answer 4

The pollen tube is more likely to reach the ovule therfore fertilsation is more likely going to occur

Question 5

Advanatges of flowering plants of increased pollen tube growth

Answer 5

Pollen tube growth likely to reach the ovule therefore fertilisation is more likely to occur

Question 6

How does crossing over 1/4

Answer 6

Chromosomes can become twisted round each other

Question 7

How does crossing over 2/4

Answer 7

This puts tension on the chromatids causing pairs of chromatids to break

Question 8

How does crossing over 3/4

Answer 8

The broken parts of the chromatids recombine with another chromatid

Question 9

How does crossing over 4/4

Answer 9

This results inn a new combination alleles

Question 10

What is independant assortment

Answer 10

Chrosomes derived from the male amd female parents are distributed into the gametes a random

Question 11

Explain how the pollen tube grows through the style of the flower

Answer 11

The enzymes are being released and used to digest the tissues of the style resulting in a pathway being formed