Cell division

Question 1

What is a gamete?

Answer 1

it is a sex cell

eg sperm, ova, pollen

Question 2

What is a haploid?

Answer 2

It is a cell or nucleus that has half the usual number of chromosomes.

Question 3

What is a diploid?

Answer 3

It is a cell or nucleus which has pairs of chromosomes

Question 4

What is mitosis?

Answer 4

Where cells replicate and make 2 identical copies of themselves

Question 5

What are the steps in mitosis?

Answer 5

1 nucleus disappears and chromosomes make copies of themselves

2. Copied chromosomes line up along the cells midpoint
3. Original chromosomes are pulled to one side of the cell and the copies to the other
4. The cell divides down the midpoint
5. A new nucleus is formed in each of the new cells.

Question 6

What are daughter cells?

Answer 6

The new cells produced by mitosis

Question 7

What is a cell cycle?

Answer 7

The steps in which the DNA material doubles and the cell divides into 2 identical cells.

Question 8

What needs to happen to a cell before mitosis can take place?

Answer 8

1. The sub cellular structures need to grow and increase so that there are enough for each daughter cell.
2. The DNA needs to double

Question 9

What is a stem cell?

Answer 9

An undifferentiated cell which can develop into a specialist cell

Question 10

What does differentiate in cells mean?

Answer 10

to specialise in a particular function

eg heart muscle cell, hair cell, skin cell

Question 11

What are the two types of stem cells?

Answer 11

Embryonic and adult

Question 12

What is an embryonic stem cell?

Answer 12

Only found in the zygote and embryo stages of reproduction, it is an unspecialised cell which can develop into one of many specialised ones.

Question 13

What is an adult stem cell?

Answer 13

They can make a few different cells eg different blood cells but not a full range of cells.
Eg those in the bone marrow which make blood cells.
some animals such as crab can regenerate limbs if they loose them

Question 14

What is a meristem of a plant?

Answer 14

where cell division happens in a plant, usually in the tips of roots or shoots

Question 15

What is a hormone?

Answer 15

is a chemical which tells a cell to do a job or change in some way

Question 16

What is a clone

Answer 16

an organism which has the same DNA as it’s parent.

Question 17

What is genetic variation?

Answer 17

the inherited differences in organisms

eg height, eye colour, number of petals

Question 18

What is environmental variation?

Answer 18

differences in the organism which have developed because of environment.
eg different size due to having different nutrients

Question 19

Give arguments for agreeing with stem cell research

Answer 19

1 . can improve the lives of people with diseases such as diabetes by replacing cells that don’t work properly.

2. can replace defective organs
3. could allow paralysed people to walk by replacing damaged nerve cells

Question 20

Give arguments against stem cell research

Answer 20

1. some religions believe that the embryo is a life with human rights
2. some people think that it is the first step in experimenting on people
3. There could be an issue with viral infections being passed on

Question 21

Where do the embryos in stem cell research come from

Answer 21

excess embryos used for IVF fertility treatment are frozen and may not be needed in the future.