17 | Cell division

Question 1

What is growth?

Answer 1

Growth occurs in all living things. It usually results in a permanent increase in size due to the increase in the number of cells in the organism. It is usually accompanied by cell differentiation to form tissues and organs.

Question 2

Growth in plants

Answer 2

• Growth is restricted to growing points such as the tips of shoots and roots.
• Growth occurs throughout the life of the plant.

Question 3

Growth in animals

Answer 3

• Grow occurs throughout the body.
• Growth stops after a certain age. (When the animal reaches maturity)

Question 4

What are the two types of cell division?

Answer 4

mitosis and meiosis

Question 5

mitosis in growth

Answer 5

Involved in growth and development
Produces genetically identical cells

Question 6

meiosis in growth

Answer 6

involved in reproduction and produces genetically varied cells (gametes)

Question 7

define mitosis

Answer 7

Mitosis is a form of nuclear division that produces two daughter nuclei containing the same number of chromosomes as the parent nucleus. The daughter nuclei are genetically identical.

Question 8

imporance of mitosis

Answer 8

GRA
- For growth of an organism by producing new cells (G)
- For repair of worn-out parts of body (R)
- For asexual reproduction (A)
– Storage organs in plants can develop roots and shoots by mitosis.
— Rhizomes and bulbs

Question 9

The need for production of genetically identical cells

Answer 9

GSU
- To ensure all the genes are correctly copied and passed down to future offspring (G)
– If an error occurs during the replication, the new DNA strand formed would be different from the original strand. This is a gene mutation and is passed on to the daughter cell.
- To produce genetically stable daughter cells which contain all the genes needed for subsequent cell division and differentiation (S)
- To prevent uncontrolled cell division (U)
– This condition is known as cancer. Cancer can be fatal

Question 10

What is the cell cycle?

Answer 10

The cell cycle is a sequence of activities that occurs from the time a cell is formed until its own division into two daughter cells.

Question 11

What are the stages of the cell cycle?

Answer 11

• Interphase (resting stage / DNA replication)
• Mitosis (nuclear division – PMAT)
• Cell division (cytokinesis – division of the cytoplasm / cleavage of cytoplasm)