CELL DIFFERENTIATION

Question 1

What are the 3 stages zygotes go through to become a specialised cell?

Answer 1

• Cell division (expansion)
• Cell differentiation ( specialisation)
• Cell death (elimination)

Question 2

What are the 3 stages of differentiation?

Answer 2

• MAINTENANCE - Cell self-renews
• EXPANSION - Cell takes signals from environment to divide into a progenitor
• DIFFERENTIATION - Cell becomes terminally differentiated and can only divide into identical cells

Question 3

Explain the 3 stages of blood cell differentiation

Answer 3

• Starts as a haemopoietic cell
• Commits into one of two progenitors - myeloid or lymphoid
• Myeloid and lymphoid divide into different cells

Question 4

Which 2 types of proteins are shared in cells?

Answer 4

• Structural
• regulatory

Question 5

Which 2 types of proteins are different in cells?

Answer 5

• Metabolic
• Proteins defining cell features

Question 6

What is cell differentiation regulated by

Answer 6

Protein expression

Question 7

What does cell differentiation rely on

Answer 7

Regulation of genes

Question 8

What do cells need in order to differentiate?

Answer 8

Signals from the extra cellular environment

Question 9

What are the two domains of transcriptional factors?

Answer 9

• DNA binding site
• Activation domain - interacts with RNA molecules

Question 10

How does the EPO cycle work

Answer 10

1) Low oxygen levels (hypoxia) are detected in the proximal tubule of the kidneys
2) This stimulates the release of EPO (erythropoietin) which promotes cell survival and differentiation
3) EPO goes to the bone marrow and stimulates stem cells to commit to become RBC progenitors
4) RBC are formed once the progenitors differentiate
5) This allows for an increased O2 carrying capacity
6) The increase in oxygen levels negatively feeds back to the kidneys and decreases the levels of EPO released

Question 11

How is EPO able to influence the bone marrow?

Answer 11

Regulates genes and gene expression which in turn regulates the proteins that are produced. Protein expression is what cell differentiation is regulated by

Question 12

Explain two clinical implications of stem cells and differentiation

Answer 12

• Deregulated differentiation results in disease e.g leukaemia which affects bone marrow and the blood
• Induced pluripotent cells can be used as a treatment - terminally differentiated cells are given 3 key transcriptional factors that result in the expression of genes that allow them to become pluripotent