B2

Question 1

What is a chromosome

Answer 1

Carries the genes

Question 2

What is a gene

Answer 2

Small packet of information that controls a characteristic - a section of DNA

Question 3

How many chromosomes and where are they stored

Answer 3

46 in nucleus - 23 pairs. In each paid, one strand is from father and one is from mother

Question 4

Three sections of cell division in order

Answer 4

Interphase, mitosis, cytokinesis

Question 5

Why is mitosis needed

Answer 5

For growth and development and to replace damaged/ worm out cells

Question 6

Stage 1 of cell cycle

Answer 6

Grows bigger, replicates DNA, forms two copies of each chromosome, increases number of sub cellular structures

Question 7

Stage 2 of cell cycle

Answer 7

Chromosomes line up in centre of cell and one strand is pulled each way, nucleus divides

Question 8

Stage 3 of cell cycle

Answer 8

Cytoplasm and cell membrane divide to form two identical daughter cells

Question 9

Products of cell division

Answer 9

Two identical daughter cells

Question 10

What is differentiation

Answer 10

When human cells turn off some genes to do a particular role

Question 11

Why do we need stem cells

Answer 11

A specialised cell can only divide by mitosis into the same type of cell. Some can’t divide at all though like blood and skin cells so we use adult stem cells to replace them

Question 12

What is a stem cell

Answer 12

Undifferentiated cell that can give rise to many different types of cells

Question 13

How long can plant cells differentiate for

Answer 13

Most of their lives

Question 14

How do meristems work

Answer 14

Undifferentiated cells are formed at active regions of the stem and roots known as meristems. Mitosis take place here almost continuously. The cells then elongate before differentiating

Question 15

When do plant cells differentiate

Answer 15

When they are at their final location

Question 16

Can plant cells re differentiate

Answer 16

Yes, they can move around the plant and change function

Question 17

Name parts of meristem

Answer 17

Zone of cell division, zone of elongation, zone of differentiation

Question 18

Cloning plants

Answer 18

Can be cloned from a tiny piece of leaf tissue, cell will unspecialise and then undergo mitosis and form different tissues, the end plant will be identical to the first plant

Question 19

What do egg and sperm cell form

Answer 19

Zygote

Question 20

Embryonic stem cells

Answer 20

Inner cells of an embryo which can differentiate into all of the specialised cells in your body

Question 21

Uses of stem cells in science

Answer 21

Embryonic injected into spinal cord to cure paralysis, embryonic stem cells transplanted into eyes to cure blindness, stem cells to produce cells that produce insulin to help diabetes

Question 22

Adult stem cells

Answer 22

Undifferentiated cell that can give rise to many more cells of similar types

Question 23

Why is cloning plants important

Answer 23

Gives a way to produce large numbers of rare plants safely and reliably - stop going extinct and for research

Question 24

Issues with using embryonic stem cells

Answer 24

Many come from aborted embryos or spare from fertility treatments, slow, difficult, expensive, and hard to control, divide rapidly so may cause cancer,

Question 25

Issues with using adult stem cells

Answer 25

May carry a virus which will be passed on to patient, may trigger immune response

Question 26

How to avoid the embryonic issues

Answer 26

Use adult stem cells, doctors have found embryonic stem cells in umbilical cord and amniotic fluid surrounding the embryo

Question 27

What is therapeutic cloning

Answer 27

Uses cells from an adult to produce a cloned early embryo of themselves

Question 28

Why is therapeutic cloning important

Answer 28

Could be used for treatments such as growing new organs for the original donor so they won’t be rejected by the body