Topic 2A Cell division and stem cells

Question 1

Where is our genetic material stored?

Answer 1

In the nucleus as chromosomes.

Question 2

What are chromosomes?

Answer 2

Chromosomes are long lengths of a molecule called DNA.

Question 3

What is the cell cycle?

Answer 3

When the body cells in multicellular organisms divide to produce new cells.

Question 4

What is mitosis?

Answer 4

When a cell reproduces itself by splitting in two to form two genetically identical offspring.

Question 5

What two processes take place at the same time?

Answer 5

Mitosis and Cytokinesis.

Question 6

What happens during the cell cycle?

Answer 6

Interphase.

Question 7

What are the 4 stages of mitosis?

Answer 7

Prophase, Metaphase, Anaphase and Telophase.

Question 7

Explain what interphase is

Answer 7

Where the cell grows, the amount of subcellular structures increase and the DNA is copied.

Question 8

Explain prophase

Answer 8

Chromosome becomes dense, membrane around the nucleus breaks down and chromosomes lie in the nucleus.

Question 9

Explain metaphase

Answer 9

Chromosomes line up at the centre of the cell.

Question 10

Explain anaphase

Answer 10

Cell fibres pull chromosomes apart. Two arms of chromosomes go to opposite ends of the cell.

Question 11

Explain telophase

Answer 11

Nucleus now divides as as membrane forms around each set of chromosomes.

Question 12

What are the uses of mitosis?

Answer 12

By multicellular organisms to grow.
By multicellular organisms to replace cells that have been damaged.
By some organisms to reproduce by asexual reproduction.

Question 13

How to calculate the the number of cells?

Answer 13

number of cells=2^n
(n is the number of divisions in mitosis)

Question 14

What processes do plants and animals grow and develop by?

Answer 14

Cell division and cell differentiation.
Plants also grow by cell elongation.

Question 15

Explain cell differentiation

Answer 15

When a cell changes to become specialised for its job.

Question 16

Explain cell elongation

Answer 16

Where a plant cell expands making the cell bigger and so making the plant grow.

Question 17

What’s growth in animals?

Answer 17

Cell division used to grow when animal is young then for repair as an adult.

Question 18

What’s growth in plants?

Answer 18

Plants height mainly due to cell elongation and cell division on the roots and shoots.

Question 19

How does change in genes affect the body?

Answer 19

A change in gene will make the cell divide uncontrollably so growth doesn’t stop and can result in tumours. This invades and destroys surrounding tissue causing cancer.

Question 20

What is a percentile chart?

Answer 20

A chart which measures a baby’s growth and development to create a pattern and problems can be spotted.

Question 21

What are stem cells?

Answer 21

Undifferentiated cells. Adult cells are used to cure disease.

Question 22

Where are stem cells found?

Answer 22

Stem cells are found in early human embryos that have the ability to divide and produce any cell.

Question 23

What may embryotic stem cells help with?

Answer 23

It may be possible to use embryonic stem cells to replace faulty cells in sick people.

Question 24

What’s an ethical issue using embryotic stem cells?

Answer 24

It is still potential life and research needs to be done to learn about potential risks.

Question 25

What are meristems?

Answer 25

Tissue found at the growing tips of plant shoots and roots. These form any type of cells in plants as long as they live.