Unit 1.1 Division & differentiation in human cells

Question 1

Name to describe an organism that consists of many cells

Answer 1

Multicellular

Question 2

What is a somatic cell

Answer 2

Any cell in the body other than cells involved in reproduction

Question 3

What do somatic cells divide by & what does this produce

Answer 3

Mitosis to produce more somatic cells

Question 4

What are somatic cells produced by

Answer 4

Cellular differentiation

Question 5

2 examples of somatic cells

Answer 5

Muscle cells, red blood cells

Question 6

What are germline cells

Answer 6

Gametes & the stem cells that divide to form gametes

Question 7

What do germline cells divide by

Answer 7

Mitosis & meiosis

Question 8

What does mitosis in germline cells produce

Answer 8

More germline cells (diploid)

Question 9

What are diploid cells

Answer 9

Cells containing 23 pairs of homologous chromosomes

Question 10

What are homologous chromosomes

Answer 10

Chromosomes of the same size, with the same genes in the same position

Question 11

What does meiosis in germline cells produce

Answer 11

Haploid gametes

Question 12

What are haploid gametes

Answer 12

Gametes (sex cells) containing 23 single chromosomes

Question 13

Differences between mitosis & meiosis in germline cells

Answer 13

Mitosis - 1 stage of division to produce 2 diploid germline cells
Meiosis- 2 stages of division to produce 4 haploid gametes

Question 14

What happens in the first division of meiosis

Answer 14

The first division separates the homologous chromosomes

Question 15

What happens in the second division of meiosis

Answer 15

The second division separates the chromatids

Question 16

What is cellular differentiation

Answer 16

The process by which a cell expresses certain genes to produce proteins characteristic for that type of cell

Question 17

What does cellular differentiation allow

Answer 17

The cell to carry out specialised functions

Question 18

What are stem cells

Answer 18

Unspecialised somatic cells with the ability to become specialised cells

Question 19

The 2 types of stem cells

Answer 19

Embryonic & tissue

Question 20

The 2 things stem cells can do

Answer 20

Reproduce & differentiate

Question 21

What does it mean for a stem cell to reproduce

Answer 21

‘Self-renews’ by carrying out mitosis to produce new cells

Question 22

What does it mean for a stem cell to differentiate

Answer 22

Change into specialised cells when required by the organism

Question 23

Are embryonic stem cells pluripotent or multipotent

Answer 23

Pluripotent

Question 24

What does pluripotent mean

Answer 24

Embryonic stem cells can differentiate into all cell types that make up the individual

Question 25

Where are embryonic cells found

Answer 25

An embryo that is 4-5 days old (blastocyst stage- ball of cells)

Question 26

Why are embryonic stem cells pluripotent

Answer 26

All the genes in embryonic stem cells can be switched on, so these cells can differentiate into any type of cell

Question 27

What are tissue stem cells also known as

Answer 27

Adult stem cells

Question 28

Are tissue stem cells pluripotent or multipotent

Answer 28

Multipotent

Question 29

What does multipotent mean

Answer 29

They can only differentiate into cell types found in that specific tissue type

Question 30

Give an example of a multipotent cell & what it can differentiate into

Answer 30

Blood stem cells (found in bone marrow) can give rise to red blood cells, platelets, phagocytes & lymphocytes

Question 31

Where are tissue stem cells found

Answer 31

In specific areas of the body (eg bone marrow)

Question 32

What do tissue stem cells do

Answer 32

They are involved in the growth, repair, & renewal of the cells found in that tissue

Question 33

What happens once a cell becomes differentiated

Answer 33

It only expresses the genes that produce the proteins characteristic for that type of cell

Question 34

What is the difference between pluripotent & multipotent stem cells

Answer 34

Pluripotent cells can differentiate into ALL cells in the INDIVIDUAL. Multipotent cells can only differentiate into cells found in a PARTICULAR TISSUE type.

Question 35

What does therapeutic uses of stem cells involve

Answer 35

the repair of damaged or diseased organs or tissues

Question 36

Examples of therapeutic uses of stem cells

Answer 36

Corneal repair, skin grafts for burn victims, & bone marrow transplants for treatment in leukaemia

Question 37

What is a cornea

Answer 37

The eyes outermost layer, which plays an important role in focussing your vision

Question 38

How can the cornea become damaged

Answer 38

By chemical burning

Question 39

How can cornea damage be treated

Answer 39

By stem cell therapy: Stem cells located in the corner of the healthy cornea can be grafted onto the damaged cornea

Question 40

Advantage of stem cell therapy in cornea repair

Answer 40

No risk that the transplanted tissue will be rejected as its the patients own stem cells

Question 41

What are skin grafts used for

Answer 41

Treating burn victims

Question 42

Explain the process of a traditional skin graft

Answer 42

It involves taking a large section of skin from a healthy region of a persons body & grafting it onto the injured site

Question 43

What is a downside to traditional skin grafts

Answer 43

The person will have 2 areas of skin to heal

Question 44

Why are using stem cells for skin grafts a good idea

Answer 44

Only a sample of skin is required to obtain stem cells

Question 45

Explain the process of skin grafts using stem cells

Answer 45

Enzymes are used to isolate the stem cells from the skin. The stem cells are then cultured in the lab. Once a suspension of new stem cells are developed, they are sprayed over the damaged area to bring around regeneration of missing skin.

Question 46

What do research uses of stem cells involve

Answer 46

Using them as model cells to study how diseases develop & drug testing. Also provides info on how cell processes work (such as cell growth & differentiation)

Question 47

Why are embryonic stem cells ideal for carrying out research on

Answer 47

They are pluripotent

Question 48

Why is it controversial to use embryonic stem cells in research

Answer 48

They offer very effective treatment for diseases & injury. However, using them destroys embryos- which many people believe is a destruction of life

Question 49

Where do the embryos used in stem cell research come from

Answer 49

They are spare embryos from IVF treatment

Question 50

Why do cancer cells divide excessively

Answer 50

They do not respond to regulatory signals

Question 51

What happens when cancer cells divide excessively

Answer 51

A mass of abnormal cells is formed (a tumour)

Question 52

How can tumours spread

Answer 52

Cells within the tumour may fail to attach to each other, spreading through the body where they may form secondary tumours