2.7 (P1) Cell Division

Question 1

Are chromosomes normally in pairs or not?

Answer 1

In pairs

Question 2

What are chromosomes made from?

Answer 2

DNA

Question 3

What are genes?

Answer 3

Short sections of DNA

Question 4

Why do cells divide?

Answer 4

To repair and grow

Question 5

What has to happen before the cell can divide?

Answer 5

Copies of genetic material has to be made

Question 6

What are the two types of cell division?

Answer 6

Mitosis

Meiosis

Question 7

Describe mitosis

Answer 7

Copies of the genetic material are made

The cell divides once to form two genetically identical body cells

Question 8

What are the properties of mitosis?

Answer 8

One cellular division
Produces diploid body cells (homologous - in pairs)
Produces genetically identical daughter cells

Question 9

Describe meiosis

Answer 9

Copies of the genetic material are made

Then the cell divides twice to form 4 gametes, each with a single set of chromosomes

Question 10

What are the properties of meiosis?

Answer 10

Two cellular division
Produces gametes (haploid)
Leads to variation
Only has one chromosome from the original pair

Question 11

What happens at fertilisation?

Answer 11

Gametes join to make a single body cell with new pairs of chromosomes

Question 12

What are cells called that are undifferentiated?

Answer 12

Stem cells

Question 13

When do most animal cells differentiate?

Answer 13

At an early stage in development

Question 14

Where can you get stem cells from?

Answer 14

Bone marrow

Embryonic stem cells

Question 15

What are the benefits of using embryos as stem cells?

Answer 15

Prevent children transferring disease
Cure diseases
Help conditions like paralysis
Grow organs instead of donors

Question 16

What are the drawbacks of using embryos as stem cells?

Answer 16

Unethical as life at conception
Expensive
Against God’s will
Most still in research phase