1.1 Differentiation & Stem Cells Flashcards Preview

Higher Biology Unit 1: Human Cells > 1.1 Differentiation & Stem Cells > Flashcards

Flashcards in 1.1 Differentiation & Stem Cells Deck (58):
1

What is cellular differentiation?

the process by which an unspecialised cell becomes altered and adapted to perform a specialised function as part of a permanent tissue.

2

When cells have differentiated what do they now have and what does that allow them to do?

a special shape or structure that allows them to carry out a specific function.

3

Once a cell becomes differentiated, what does it only express?

the genes that produce the proteins characteristic for that type of cell.

4

State how the cell structure of a ciliated epithelial cell relates to its function?

It has cilia which are like tiny hairs which beat rhythmically to sweep dirt and microorganisms upwards and away from the lungs.
In the trachea and Fallopian tubes/oviduct

5

State how the cell structure of a nerve cell relates to its function?

Long axons increase its surface area to allow electrical impulses to be passed onto other nerve cells.
Myelin sheath surrounds axons and insulates it which speed up electrical impulses.

6

State how the cell structure of a red blood cell relates to its function?

Biconcave disc shape gives it a larger surface area for transporting oxygen
It has no nucleus therefore there is more room for haemoglobin so more oxygen can be carried
It is small and flexible so it can fit through small blood vessels e.g. capillaries

7

State how the cell structure of a goblet cell relates to its function?

Secretes mucus to trap dirt and microorganisms
In the windpipe

8

What are tissues?

Groups of specialised cells which work together to perform a similar function

9

Give 4 examples of different tissues and their function?

Epithelial - forms a continuous sheet over body surfaces and inner body cavities
Connective - variety of functions - stores fat, fills spaces, provides support, forms blood cells - includes bone, blood and cartilage cells
Muscle - to produce force and cause movement, either locomotion or movement within internal organs
Nervous - Transmit messages in the form of electrical impulses

10

What are the levels of organisation in humans?

cells>tissues>organs>systems>organism

11

What are stem cells?

unspecialised cells that can divide to make copies of themselves (self-renew) and/or differentiate into specialised cells.

12

What are most of genes present in the DNA of stem cells?

they are still ''switched on'' so they can develop into different cell types

13

What are the 2 main types of stem cells?

embryonic stem cells
tissue (adult) stem cells

14

What are embryonic stem cells derived from?

an embryo that is about 4-5 days old, known as a blastocyst

15

What are embryonic stem cells called and what does this mean?

They are called pluripotent. This means the embryonic stem cells can develop into any of the 200 plus cell types of the adult body.

16

How is the use of embryonic stem cells very controversial?

Because research using embryonic stem cells involves the destruction of embryos.

17

What do those who support the use of embryonic stem cells say?

that it is left over embryos from fertility treatment which are used.
Once the time limit for keeping spare embryos is up, they are destroyed anyways, it is better not to waste them, but to use them in research that could benefit people.

18

What is the only specialised cells in which embryonic cannot become?

placental cells

19

What can adult tissue stem cells be used to do?

replace cells that die or restore tissue after injury

20

Give 4 examples of tissues which contain there own stem cells?

skin
muscle
intestine
bone marrow

21

What are adult tissue stem cells called and what does this mean?(3)

They are called multipotent. This means they have the ability to divide into only several distinct cell types, usually similar to the tissue which surrounds them. They give rise to a more limited range of cell types, compared to embryonic stem cells.

22

What is bone marrow?(2)

the tissue found in the centre of larger bones and is the place where new blood cells are produced.

23

What are the 3 types of blood cells produced from bone marrow?

red blood cells
white blood cells
platelets

24

What do white blood cells do?

fight disease

25

What do platelets do?

clot the blood

26

What are the 5 types of white blood cells?

lymphocyte
monocyte
eosinphil
basophil
neurophil

27

What is a benefit of the use of adult tissue stem cells?

They are beneficial in therapy because most of the time the patient's own stem cells can be harvested for use, this means that rejection of tissue will not be an issue.

28

Give 5 examples of therapeutic applications of stem cells?

Bone Marrow stem cell transplantation for leukemia
Skin grafts
Corneal grafts
Parkinson's disease
Windpipe transplant

29

What do the stem cells used to treat leukemia stimulate?

new bone marrow growth and restore the immune system

30

Before the stem cell transplant to treat leukemia what must the patient undergo?

an intense course of chemotherapy to destroy as many cancerous cells as possible.

31

How is the bone marrow stem cell transplantation for leukemia happen?

Happens intravenously, similar to a blood transfusion. Once the stem cells enter the bloodstream they travel to the bone marrow and start making new blood cells

32

What can stem cells which are genetically identical to differentiated somatic cells be used in research as?

model cells

33

What can stem cells used as models be used to do?

investigate the responses of cells to new drugs or to obtain a fuller understanding of cell development and processes such as growth and differentiation.

34

What are somatic cells?

differentiated cells that form the different types of tissue that exist.

35

What types of cells are somatic, give 3 examples?

All body cells apart from gametes (sex cells)
e.g.
skin cells
nerve cells
muscle cells

36

How do somatic cells divide to form more somatic cells?

by mitosis

37

How many sets of chromosomes do somatic cells have and therefore what are they called?

2 sets of chromosomes therefore they are diploid

38

What are unspecialised somatic cells also known as?

stem cells

39

What is a germline cell?

is one that will become a gamete e.g. egg cell or sperm cell OR the cells that produce gametes.

40

How do germline cells divide to produce more germline cells?

by mitosis

41

How do germline cells divide to produce haploid gametes?

by meiosis

42

What type of cells, somatic or germline, can mutations be passed onto offspring?

germline

43

What is meiosis?

a form of nuclear division, similar to mitosis, which produces haploid gametes, each with 23 chromosomes

44

What do cancer cells do?

they divide uncontrollably to produce a mass of abnormal cells.

45

What do healthy cells have that cancer cells don't?

various checkpoints at which their cell cycle is controlled.

46

What is a cell cycle?

a series of events that take place in a cell leading up to its division.

47

In healthy cells what happens to the cell if mistakes are made during the cell cycle?

it undergoes apoptosis (cell suicide)

48

What is wrong with cancer cells?

the checkpoints fail and as a result, they do not respond to any regulatory signals.

49

What could failure of checkpoints in cancer cells be due to?

genetic or environmental factors

50

What is a tumour?

a mass of abnormal cells which divide uncontrollably

51

What is a benign tumour?

a tumour that doesn't metastasise i.e. spread to other areas of the body

52

Give 2 examples of benign tumours?

moles
warts

53

What is a malignant tumour?

a tumour that does metastasis i.e. can spread to other parts of the body

54

What cells within a malignant tumour said to be?

Cancerous

55

What do cells in a malignant tumour not do?

respond to regulatory signals and may fail to attach to each other

56

What happens if cancer cells do not attach to each other?

they can spread throughout the body forming secondary tumours

57

What can increase the risk of cancer, give 8 examples?

age
cigarette smoke
pollution
ultraviolet radiation
genetic mutation
hereditary
diet
infection

58

Why does age increase the risk of cancer?

it normally takes a very long time for a cell to be affected by several different mutations.