Sexual Reproduction in Plants (Cambridge O Level Biology)

The diagrams show 3 different species of pollen grains as they appear under a microscope. The diagrams are all to the same scale.

Which pollen grains are involved in insect pollination?

The diagram below shows a flower.

Which of these processes have taken place?

	pollination	fertilisation
A	no	no
B	no	yes
C	yes	yes
D	yes	no

An experiment was set up with four test tubes as shown in the diagram below and placed in the dark.

In which conditions would the seeds germinate first?

Germinating seeds were placed in different temperature and light conditions as shown in the table below.

sample	temperature / °C	light
1	20	absent
2	20	present
3	4	absent
4	4	present

A seedling was removed from each experiment after 7 days.

Which seedling was from sample 2?

Six bean seeds were soaked in cold water. Three of them were boiled and cooled. The boiled and the non-boiled seeds were chopped up and then placed on the surface of agar jelly containing starch. 

After two days, all the seeds were removed and the jelly was tested with iodine solution. 

The diagram shows the result of the experiment.

What is the explanation for the results with the non-boiled bean seeds?