Cell Differentiation

Question 1

How single zygote develops (3 stages)

Answer 1

Cell division
Cell specialisation
Cell death apoptosis

Question 2

Differentiation has three steps:

Answer 2

1. Maintenance: stem cells self renew
2. Expansion: receive signals. Then commit and form progenitors
3. Differentiation: becomes terminally different

Question 3

What are progenitors?

Answer 3

Only differentiate into a limited number of cells

Question 4

Cells potency and how it decreases?

Answer 4

A cells ability to produce different terminally differentiated cells

Potency decreases as cells commit down differentiation pathways

Question 5

Importance of cell differentiation

Answer 5

1. Repair damage
2. Cells become specialised and form tissues and organs

Question 6

What makes cells different to another?

Answer 6

Different cells have different patterns of gene expression so have distinct functional roles due to diff proteins they express

Question 7

House keeping genes?

Answer 7

constitutive genes required for the maintenance of basic cellular function, they are expressed in all cells under normal conditions

Question 8

TF are modular because contain two parts:

Answer 8

1. Activation domain - interacts with RNA polymerase
2. DNA binding domain - recognises and binds to promoter/ enhancer regions

Question 9

Problems with progenitors:

Answer 9

• mutation occurs in stem cell/ progenitors
• stem cells over proliferate
• causes accumulation of progenitors (tumour)
• mutation stops progenitor from differentiating

Question 10

What are multipotent cells

Answer 10

Become different number of cells but not every

Question 11

What are pluripotent

Answer 11

Become any cell in the body

Question 12

What are unipotent cells

Answer 12

Can only differentiate into specialised cells

Question 13

The order of stem cells

Answer 13

Pluripotent
Multipotent
Unipotent

Question 14

Example of multipotent cell

Answer 14

Hematopoietic stem cell

Question 15

What is an Oligopotent cell

Answer 15

able to self-renew and form 2 or more lineages within a specific tissue

Question 16

What is oligopotency

Answer 16

the ability of progenitor cells to differentiate into a few cell types.
It is a degree of potency

Question 17

What makes cells different from one another

Answer 17

• Distinct functional roles
• Different proteins (associated with functions)
- Proteins defining cell type features Unique - Metabolic proteins
- Structural proteins
- Regulatory proteins

Question 18

Molecular control of red blood cell

Answer 18

a/b globins
Carbonic anhydrase
Spectrin
Anion transporter

Question 19

Molecular control of platelet production

Answer 19

Thrombin receptor
Collagen receptors
Fibrinogen receptor
Granule proteins

Question 20

Examples of proteins that regulate red cells/ erythrocytes

Answer 20

• Cell feature-defining proteins (e.g. haemoglobin)
• Metabolic proteins (e.g. carbonic anhydrase)
• Structural proteins (e.g. spectrins)
• Regulatory proteins (e.g. GATA-1, a transcription factor)

Question 21

How is a cells phenotype dictated

Answer 21

By its constituent proteins

Question 22

Are transcriptional factors modular

Answer 22

Yes

Question 23

What is critical in cell specialisation

Answer 23

Transcription

Question 24

How do TF control differentiation

Answer 24

Different TF control different steps of differentiation
Different essential TF for each specialised cell

Question 25

Key concepts of cell differentiation

Answer 25

Cell needs extracellular signals to expand and differentiate
Different transcription factors control different steps of differentiation

Question 26

What is erythropoietin

Answer 26

Stimulated by Extracellular signal

Secreted by kidneys
That increases the rate of production of red blood cells
In response to falling levels of oxygen

Question 27

Erythropoietin cycle

Answer 27

Low O2 in proximal tubule
Epo
Bone - stimulates stem cells
RBC progenitors
Increased O2 negatively feeds back on Epo

Question 28

How Epo regulates red cell specific genes

Answer 28

Epo receptor in cell membrane
Gene regulatory protein is activated
Binds to regulatory DNA
Provoking activation of a gene to produce another protein
That binds to other regulatory regions and protein coding regions

Signalling cascade
RBC gene turned on