Chapter 2 🤕

Question 1

What is mitosis?

Answer 1

When the genetic material in a cell is doubled and then the cell splits into two identical nuclei

Question 2

What happens in stage 1 of the cell cycle?

Answer 2

The cells grow and increase their mass
DNA is replicated to form two sets of each chromosome
Increased numbers of mitochondria, ribosomes and chloroplasts

Question 3

What happens in stage 2 of the cell cycle?

Answer 3

Mitosis: one set of chromosomes is pulled to each end of the dividing cell
Nucleus divides

Question 4

What happens in stage 3 of the cell cycle?

Answer 4

The cytoplasm and cell membrane divides to form two identical daughter cells

Question 5

What is a stem cell?

Answer 5

An unspecialised cell

Question 6

When do most animal cells differentiate?

Answer 6

Early stage of life

Question 7

What can embryonic and adult stem cells do?

Answer 7

Embryonic stem cells and adult stem cells can be cloned and made to differentiate into different types of cell

Question 8

Examples of conditions that may be helped by stem cells

Answer 8

Paralysis and diabetes

Question 9

Problems with embryonic stem cells

Answer 9

Ethical -> come from aborted embryos
Progress is slow and expensive
They grow and divide rapidly -> cancer?

Question 10

How many chromosomes are in each cell’s nucleus?

Answer 10

46, arranged in 23 pairs

Question 11

What is the cell cycle?

Answer 11

How body cells divide

Question 12

Why is mitosis important?

Answer 12

Growth
Repair
Development

Question 13

What is differentiation?

Answer 13

When a cell becomes specialised to carry out a particular job

Question 14

What do adult stem cells do?

Answer 14

Replace cells that can’t divide like RBCs and skin cells

Question 15

When can most plant cells differentiate?

Answer 15

All through their lives

Question 16

What is cloning?

Answer 16

Producing identical offspring

Question 17

What is a zygote?

Answer 17

When a sperm and egg fuse to form a single cell

Question 18

What is a good source of adult stem cells?

Answer 18

Bone marrow

Question 19

Why are stem cells used to treat various diseases?

Answer 19

They differentiate to form the cells needed to treat the disease

Question 20

Why are stem cells important in plants?

Answer 20

It allows us to make large numbers of rare plants reliably and safely

Question 21

What is an ethical issue of stem cells?

Answer 21

Embryonic stem cells come from aborted embryos

People see this as a violation of the embryos rights as they can’t consent

Question 22

Economic problem with stem cells

Answer 22

Progress is slow, difficult and expensive

Question 23

Illness problems with stem cells

Answer 23

Grow and divide rapidly -> cancer?

Could be infected with viruses and transfer it to patient

Question 24

What is therapeutic cloning?

Answer 24

Using cells from an adult to produce a cloned embryo of themselves to provide embryonic cells

Question 25

What are stem cells currently being researched to treat

Answer 25

``` Spinal cord injuries Diabetes Heart after a heart attack Blindness Damaged bone and cartilage ```

Question 26

what is binary fission?

Answer 26

how bacteria cells divide, they split in two

Question 27

in binary fission, how does a cell divide?

Answer 27

1. duplicates DNA 2. increases size and moves one set of DNA to each end of cell 3. cytoplasm divides and new cell walls are made 4. two daughter cells are made

Question 28

what is the mean division time of a bacteria cell

Answer 28

the average time it takes a bacteria cell to divide into two

Question 29

what is a culture medium for bacteria?

Answer 29

contains the foods and nutrients it needs to grow

Question 30

what is differentiation?

Answer 30

when stem cells change to become specialised for its job

Question 31

how can stem cells be used to preserve rare species of plant?

Answer 31

stem cells can be taken and grown to produce identical clones

Question 32

where are stem cells found in plants?

Answer 32

the meristem - where growth occurs

Question 33

what are chromosomes made from?

Answer 33

genes

Question 34

Which stage of the cell cycle is variable?

Answer 34

Stage 1