Growth questions | form four Biology

Define the term mitosis

Answer / Solution

Mitosis: Is a process where by a single cell divides to form two identical cells.

Outline the significance of mitosis to organisms

Answer / Solution

.The following are the importance of mitosis to organisms.,

1. Growth and development: Mitosis is the basis for cell division which leads to growth.
2. Cell replacement: Every day most of cells die, hence mitosis creates copies of the dead cells which replace them.
3. Regeneration: Most organisms have the ability to regenerate their lost body parts because of mitosis for example starfish.
4. Asexual reproduction: Mitosis is very important in asexual reproduction. for example in vegetative propagation in plants and budding in hydra.

Define the following terms and give an example of an organism where each takes place

• Complete metamorphosis
• Incomplete metamorphosis
• Ecdysis

Answer / Solution

• Complete metamorphosis: Is a type of metamorphosis in  which an insect passes through the egg, larval, pupal, and adult stages of growth.
• Incomplete metamorphosis: Is a type of metamorphosis in which an insect does not pass the  pupal stage in its growth. That is egg, larval and adult stage.
• Ecdysis: Is the shedding of an outer integument or layer of skin, as by insects, crustaceans, and snakes. It is also known as  molting.

Explain the following observations

• Lighting shoot from one side makes a t bend towards light
• The shoot of the seedling kept in adark place sideways( horizontally ) grows upwards while its roots grow downwards

Answer / Solution

UNSOLVED

The number of chromosomes in a fertilized egg in man that will grow into a male child is.

• 22 pairs + xx
• 22 pairs + xy
• 22 pairs + y
• 22 + y

Answer / Solution

b.[22 pairs + xy]