L4 Differentiation

Question 1

What does cell diversity primarily result from?

Answer 1

Cell diversity primarily results from differences in gene expression

Question 2

All cells have the same gene content ….?

Answer 2

All cells have the same gene content, but different sets of proteins

Question 3

What does terminally differentiated state mean?

Answer 3

Refers to the final stage of cellular differentiation. They are dedicated to performing their specific roles within the organism

Question 4

What do cells change their expression profile in response to?

Answer 4

Cells change their expression profile in response to signals and other cues in the environment

Question 5

Do cells express a fraction of their gene?

Answer 5

Yes

Question 6

In what state do cells often express different genes?

Answer 6

In a disease state.

Question 7

What are the 5 stages of potency within cells?

Answer 7

• Totipotent
• Pluripotent
• Multipotent
• Bipotent
• Unipotent

Question 8

What is the highest level of potency?

Answer 8

Totipotent. A totipotent cell can differentiate into any cell type.

Question 9

Does the level of transcription affect the level of expression?

Answer 9

Yes, increasing the level of transcription tends to increase the expression of a gene

Question 10

What does transcriptome do?

Answer 10

They transcript genes into RNA

Question 11

What is proteome?

Answer 11

Translate RNA into amino acids to make protein

Question 12

What do DNA binding proteins bind to?

Answer 12

DNA binding proteins bind to the DNA backbone and reach into the major groove to form very specific bonds.

Question 13

What are the other names for a binding site?

Answer 13

1. Cis acting element
2. Regulatory element
3. Enhancer
4. Silencer

Question 14

What is a binding site?

Answer 14

A binding site is a stretch of DNA with a sequence that is recognised and bound by the transcription factor. The bonds are H - bonds and are not stable

Question 15

What are silencers?

Answer 15

They are the binding site for transcriptional repressors

Question 16

What are enhancers?

Answer 16

They are the binding site for transcriptional activators.

Question 17

Give me examples of inputs that can be referred to as a genetic switch

Answer 17

• Strongly activating assembly
• Strongly inhibiting protein
• Spacer DNA
• Weakly activating protein assembly

Each switch is responding to extrinsic or instrinsic regulation

Question 18

What is an expression profile?

Answer 18

It essentially provides a snapshot of which genes are actively being transcribed in a cell or tissue at a particular time

Question 19

Can a single transcription factor create an expression profile ?

Answer 19

Yes

Question 20

What does “Enhancer are promiscuous” mean?

Answer 20

This means that they will work on any gene.

Question 21

In summary, what is transcription factor activity dependent on? (3)

Answer 21

Extrinsic signals
Intrinsic factors
Regulatory binding sites

Question 22

Give me 4 examples of muscle specific proteins

Answer 22

• Muscle - specific actin
• Myosin II
• Tropomyosin
• Muscle-specific enzymes (e.g. creating phosphate kinase)

Question 23

What is MyoD?

Answer 23

Gene and transcription factor

Question 24

What does transfect mean?

Answer 24

Transfect = introduce a modified gene into cells or an animal (to make a transgene)

Question 25

What’s the difference between genes being sufficient or necessary/ required?

Answer 25

A gene is required for a particular process or outcome of that process cannot occur without the gene’s presence A gene is sufficient for a particular process or outcome if its presence alone is enough to cause that process to occur

Question 26

In the embryo where does most muscle cells comes from?

Answer 26

They come from somites.

Question 27

In adults where does muscle cells come from?

Answer 27

In the adult, muscle cells are renewed by satellite stem cells that line muscle fibres

Question 28

Do transcription factors bind in clusters or not?

Answer 28

They bind in clusters