Cells

Question 1

Define a eukaryotic cell

Answer 1

Contain DNA enclosed in a nucleus

Question 2

Define prokaryotic cell

Answer 2

Genetic material isn’t enclosed in a nucleus

Question 3

Diff between prokaryotic and eukaryotic

Answer 3

Prokaryotic
- small no nucleus
- binary fission
- dna is free in cytoplasm

Eukaryotic
- larger
- dna in nucleus
- mitosis

Question 4

Describe a stem cell

Answer 4

Undifferentiated cell which can give rise to more cells of the same type
Can differentiate to form other types of cells

Question 5

Where are stem cells in humans

Answer 5

Found in bone marrow differentiate to form cells found in blood eg rbc, wbc

Question 6

Use of stem cells to adults

Answer 6

Leukaemia is cancer of bone marrow
- treated by patients pre existing bone marrow destroyed by radiation
- patient receives transplant of bone marrow from donor
- stem cells in bone marrow divide and form new bone marrow
= differentiate and form blood cells

Question 7

Problems with bone marrow transplants

Answer 7

• donor must be compatible with patient otherwise WBC produced by bone marrow could attack patients body
• risk that viruses can be passed from donor to patient

Question 8

Describe therapeutic cloning

Answer 8

Embryo produced with same genes as patient
= stem cells from embryo can be transplanted into patient without being rejected by patients immune system
= once inside patient stem cells can differentiate to replace cells which have stopped working

Question 9

Use of therapeutic cloning

Answer 9

• treat medical condition like diabetes or paralysis

Question 10

Problems with therapeutic cloning

Answer 10

Ethical or religious objections to procedure

Question 11

Describe stem cells in plants

Answer 11

Meristem tissue
= can differentiate into any type of plant tissue at any point in life of plant

Question 12

Use of meristem tissue

Answer 12

Produce clones of rare plants to strop from going extinct
Produce cloned crop plants for farmers