Unit 1.1 Division & differentiation in human cells Flashcards

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1
Q

Name to describe an organism that consists of many cells

A

Multicellular

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2
Q

What is a somatic cell

A

Any cell in the body other than cells involved in reproduction

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3
Q

What do somatic cells divide by & what does this produce

A

Mitosis to produce more somatic cells

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4
Q

What are somatic cells produced by

A

Cellular differentiation

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5
Q

2 examples of somatic cells

A

Muscle cells, red blood cells

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6
Q

What are germline cells

A

Gametes & the stem cells that divide to form gametes

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7
Q

What do germline cells divide by

A

Mitosis & meiosis

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8
Q

What does mitosis in germline cells produce

A

More germline cells (diploid)

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9
Q

What are diploid cells

A

Cells containing 23 pairs of homologous chromosomes

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10
Q

What are homologous chromosomes

A

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

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11
Q

What does meiosis in germline cells produce

A

Haploid gametes

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12
Q

What are haploid gametes

A

Gametes (sex cells) containing 23 single chromosomes

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13
Q

Differences between mitosis & meiosis in germline cells

A

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

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14
Q

What happens in the first division of meiosis

A

The first division separates the homologous chromosomes

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15
Q

What happens in the second division of meiosis

A

The second division separates the chromatids

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16
Q

What is cellular differentiation

A

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

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17
Q

What does cellular differentiation allow

A

The cell to carry out specialised functions

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18
Q

What are stem cells

A

Unspecialised somatic cells with the ability to become specialised cells

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19
Q

The 2 types of stem cells

A

Embryonic & tissue

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20
Q

The 2 things stem cells can do

A

Reproduce & differentiate

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21
Q

What does it mean for a stem cell to reproduce

A

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

22
Q

What does it mean for a stem cell to differentiate

A

Change into specialised cells when required by the organism

23
Q

Are embryonic stem cells pluripotent or multipotent

A

Pluripotent

24
Q

What does pluripotent mean

A

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

25
Q

Where are embryonic cells found

A

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

26
Q

Why are embryonic stem cells pluripotent

A

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

27
Q

What are tissue stem cells also known as

A

Adult stem cells

28
Q

Are tissue stem cells pluripotent or multipotent

A

Multipotent

29
Q

What does multipotent mean

A

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

30
Q

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

A

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

31
Q

Where are tissue stem cells found

A

In specific areas of the body (eg bone marrow)

32
Q

What do tissue stem cells do

A

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

33
Q

What happens once a cell becomes differentiated

A

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

34
Q

What is the difference between pluripotent & multipotent stem cells

A

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

35
Q

What does therapeutic uses of stem cells involve

A

the repair of damaged or diseased organs or tissues

36
Q

Examples of therapeutic uses of stem cells

A

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

37
Q

What is a cornea

A

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

38
Q

How can the cornea become damaged

A

By chemical burning

39
Q

How can cornea damage be treated

A

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

40
Q

Advantage of stem cell therapy in cornea repair

A

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

41
Q

What are skin grafts used for

A

Treating burn victims

42
Q

Explain the process of a traditional skin graft

A

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

43
Q

What is a downside to traditional skin grafts

A

The person will have 2 areas of skin to heal

44
Q

Why are using stem cells for skin grafts a good idea

A

Only a sample of skin is required to obtain stem cells

45
Q

Explain the process of skin grafts using stem cells

A

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.

46
Q

What do research uses of stem cells involve

A

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)

47
Q

Why are embryonic stem cells ideal for carrying out research on

A

They are pluripotent

48
Q

Why is it controversial to use embryonic stem cells in research

A

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

49
Q

Where do the embryos used in stem cell research come from

A

They are spare embryos from IVF treatment

50
Q

Why do cancer cells divide excessively

A

They do not respond to regulatory signals

51
Q

What happens when cancer cells divide excessively

A

A mass of abnormal cells is formed (a tumour)

52
Q

How can tumours spread

A

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