Producing new cells

Question 1

What is the importance of cell division?

Answer 1

Single cell organisms use cell division as a means of reproduction. In multicellular organisms, cell division makes new cells for growth or to repair damage (cuts, broken bones)

Question 2

What do chromosomes do in cell division?

Answer 2

Chromosomes carry the instructions for making all of our proteins.

Question 3

One gene is…

Answer 3

The instruction for 1 protein

Question 4

What do genes do?

Answer 4

Genes determine our characteristics.

Question 5

When do we see chromosomes?

Answer 5

During cell division (only)

Question 6

How many sets of chromosomes do sex cells have?

Answer 6

1 set (23 chromosomes)

Question 7

How many sets of chromosomes do cells (not sex cells) have?

Answer 7

2 sets- 1 set from mum and 1 set from dad (46 chromosomes)

Question 8

What is a diploid cell?

Answer 8

A cell with 2 sets of chromosomes.

Question 9

What is a diploid number?

Answer 9

The number of chromosomes in total in the two sets combined (eg, 46-humans).

Question 10

When a cell divides, why must the diploid number be maintained?

Answer 10

So that each new cell receives a full set of genetic information which is vital as it controls cell development and all cell activities.

Question 11

In cell division, what: carry the instructions for making all of our proteins?

Answer 11

Chromosomes.

Question 12

What determines our characteristics?

Answer 12

Genes.

Question 13

What is: MITOSIS?

Answer 13

The division of the nucleus which ensures that each of the two daughter cells will contain the same number of chromosomes as the original parent cell, and be genetically identical to it.

Question 14

Explain the stages of mitosis.

Answer 14

The chromosomes are replicated and become visible.
Each consists of two strands called chromotids, joined at a point: centromere.
Nuclear membrane starts to break down and spindle forms.
The chromosomes line up along the equator of the cell, attatched to the spindle by their centromeres.
The spindle contracts, which pulls the chromosomes apart to opposite ends of the cell.
The chromosomes reach opposite end of the cell and new nuclear membrane forms round each set of chromosomes.
The cell divides into two daughter cells when the cytoplasm divides.
(then different things in animal and plant cells)

Question 15

What happens at the end of division in a: PLANT CELL?

Answer 15

A new cell wall forms, separating cytoplasm.

Question 16

What happens at the end of division in a: ANIMAL CELL?

Answer 16

Divison occurs when cytoplasm constricts.

Question 17

In division of a cell, what cell type does this happen in: Divison occurs when cytoplasm constricts?

Answer 17

An animal cell.

Question 18

In division of a cell, what cell type does this happen in: A new cell wall forms, separating cytoplasm?

Answer 18

A plant cell.

Question 19

In cell culture, what are 3 requirements?

Answer 19

A sterile environment, free from contaminants that might act as competitors.
An appropriate growth medium.
A controlled environment to provide optimum conditions.

Question 20

In cell culture, what are 3 optimums that are required?

Answer 20

Optimum level of oxygen.
Optimum pH of the medium
Optimum temperature

Question 21

What must the culture medium contain?

Answer 21

An energy source such as glucose, and nutrients for building new cells.

Question 22

What are: ASEPTIC TECHNIQUES?

Answer 22

Laboratory procedures designed to prevent contamination when working with micro-organisms or other cell cultures.