P1 4.1.2 Cell division (might come up)

Question 1

Where are chromosomes contained

Answer 1

Nucleus

Question 2

What are chromosomes made of

Answer 2

thin strands of DNA

Question 3

What do chromosomes contain

Answer 3

A large number of genes and short sections of DNA

Question 4

How many chromosomes do we have

Answer 4

23 pairs

Question 5

What is mitosis

Answer 5

When a cell reproduces itself by splitting to form 2 identical daughter cells

Question 6

What is mitosis for

Answer 6

To grow and develop or replace cells that have been damaged

Asexual reproduction

Question 7

What is and what happens during the first few stages of the cell cycle

Answer 7

Growth and replication

1. Increases the amount of subcellular structures
2. It duplicates its DNA so there’s one copy of each chromosome for each new cell. The DNA forms X-shaped chromosomes

Question 8

What happens during the mitosis stage of the cell cycle

Answer 8

3. The chromosomes line up at the centre of the cell then cell fibres pull them apart. The 2 arms of each chromosome go to opposite ends of the cell
4. Membranes form around each of the sets of chromosomes - the nucleus has divided
5. The cytoplasm and cell membrane divide

Question 9

What is a stem cell

Answer 9

They are undifferentiated cells and are capable of developing into different types of cell
They can also divide to provide more undifferentiated cells

Question 10

Where are stem cells found

Answer 10

In early human embryos

Bone marrow - not as versatile

Question 11

Uses and future uses for stem cells

Answer 11

To cure disease eg sickle cell anaemia (shape of red blood cells) - bone marrow stem cells can replace faulty blood cells
Future - replace faulty cells in sick people

Question 12

Risks and issues of stem cells

Answer 12

Stem cells grown in a lab may become contaminated with a virus which could be passed on to the patient and make them sicker
Some people think human embryos shouldn’t be used for experiments since each one is a potential human life
However others think curing patients who already exist and are suffering is more important than embryos

Question 13

What is therapeutic cloning

Answer 13

An embryo is produced with the same genes as the patient. Stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment

Question 14

Uses of stem cells in meristems (plants)

Answer 14

Growing more plants of a rare species (prevents being wiped out)
Growing crops of identical plants that have desired features