Mitosis

Question 1

What does the nucleus contain

Answer 1

Your genetic material in the form of chromosomes

Question 2

What are chromosomes

Answer 2

Coiled up lengths of DNA molecules

Question 3

What do genes do

Answer 3

They control the development of different characteristics

Question 4

What do chromosomes carry

Answer 4

Large number of genes

Question 5

How many copies of chromosomes do bodies cells have

Answer 5

They have two copies of each chromosome - one from the father and one from the mother

Question 6

How many pairs of chromosomes do humans have

Answer 6

23 pairs

Question 7

How many chromosomes do humans have

Answer 7

46

Question 8

What is mitosis

Answer 8

The stage of the cell cycle when it divides

Question 9

1st stage of cell cycle - growth and repair

Answer 9

At the start of interphase the new cells, formed by mitosis and cytokinesis grow
Then the DNA and organelles, such as mitochondria, are replicated ready for cell division
A cell is interphase for the majority of its lifespan

Question 10

2nd stage of cell cycle - mitosis

Answer 10

4) At the start of mitosis chromosomes condense making them visible under a microscope
5) the chromosomes line up in pairs at the centre of the cell and the cell fibres pull them apart. The two arms of each chromosome go to the opposite ends of of the cell
- membranes form around each of the sets of chromosomes, these become nuclei of the two cell, the nucleus then divides

Question 11

What is differentiation

Answer 11

The process when a cell changes to become specialised for its job

Question 12

What are stem cells

Answer 12

Undifferentiated cells that can develop into one or more types of specialised cell

Question 13

What can stem cells do

Answer 13

They can differentiate into different types of cells depending what instructions they are given and can divide to produce lots more undifferentiated cells

Question 14

Where are embryonic stem cells found

Answer 14

Early human embryos

Question 15

Where are adult stem cells found

Answer 15

Bone marrow

Question 16

Difference between embryonic stem cells and adult stem cells

Answer 16

Adult stem cells can only turn into certain types of cells whilst embryonic stem n turn into any kind of cell

Question 17

What can stem cells from embryonic and bone marrow do

Answer 17

• they can be grown in a lab to reduce clones and differentiate into specialised cells to use in medicine or research

Question 18

How are adult stem cells used to cure disease

Answer 18

The stem cell is transferred from the bone marrow of a healthy person to replace the fatty blood cells in a sick patient

Question 19

How can embryonic stem cells be used in medicine

Answer 19

• they can replace fatty cells in sick people
• they can be used to make insulin producing cells for people with diabetes
• they can be used to make nerve cells for people paralysed by spinal injuries

Question 20

How does therapeutic cloning works

Answer 20

An embryo is made to have the same genetic information as the patient so the stem cells produced from it would also contain the same genes and would be rejected by the patients immune system and once inside the patient the stem cells can then differentiate to replace cells which have stopped working correctly

Question 21

Risks of stem cells in medicine

Answer 21

• stem cells grown in labs may be contaminated with a virus which could be passed onto a patient, making them sicker

Question 22

Why are some people against stem cell research

Answer 22

• as they feel that human embryos should not be used for experiments since each one is a potential human life
• they feel that scientists should concentrate more in finding and developing other sources of stem cells so people could be helped without having to use embryos

Question 23

Why are some people for stem cell research

Answer 23

• they argue that embryos used in research are usually unwanted ones from fertility clinics so if they weren’t used for research they would be destroyed
• they think curing patients who are suffering is more important than the rights of embryos

Question 24

Where are stem cells found in plants

Answer 24

Meristem

Question 25

What are the stem cells in plants used for in agriculture

Answer 25

• to produce clones of the whole plant quickly and cheaply
• to grow more plants of rare species to prevent them being wiped out
• to grow crops of identical plants that have desired features for farmers

Question 26

How are embryos formed

Answer 26

1)sperm cell joins with the ovum through fertilisation
2) the fertilised ovum goes under mitosis and forms a ball of cells called an embryo

Question 27

Bone marrow transplant - how to treat leukaemia

Answer 27

1) the patient existing bone marrow is destroyed using radiation
2) the patient then receives a transplant of bone marrow from a donor
3)the stem cells in the bone marrow divide and form a new bone marrow and can also differentiate to form blood cells

Question 28

Disadvantages of bone marrow transplant

Answer 28

• donor has to be compatible with the patient or the white blood cells produces by the donated bone marrow could attack the patient’s body
• risk that viruses can be passed from the donor to the patient

Question 29

What medical conditions do therapeutic cloning help with

Answer 29

• diabetes
• paralysis

Question 30

How long can plant cells differentiate for

Answer 30

Throughout the plants life

Question 31

What is leukaemia

Answer 31

Cancer in the bone marrow

Question 32

what happens in cytokenesis - stage 3

Answer 32

8) the cytoplasm and the cell membrane divides and this produce two daughter cells which are genetically identical and their DNA is also identical to the parent cell