14- Epigenetics

Question 1

How does gene expression change?

Answer 1

Changes occur overtime in different tissue

Question 2

What are gene expressions modified by?

Answer 2

Transcription factors
Non- protein- coding RNAs
Imprinting and Methylation

Question 3

How is transcription activated?

Answer 3

DNA packaged in chromsome
Activator binds regulatory elements
Transcription factors and RNA polymerase recruited
Transcription activated

Question 4

What are the transcription factors that control gene expression?

Answer 4

Molecular switches whose actions is to facilitate transcription of a gene by helping bring RNA polymerase to the promoter

Question 5

What is the role of the transcription factors?

Answer 5

Development:morphology, differentiation 
Response to intercellular signals 
Response to pathogens 
Cell cycle control 
Response to environmental signals 
Response to intercellular signals

Question 6

How do microRNAs function?

Answer 6

Regulate the expression of many mRNAs by binding to sequences in the 3’ untranslated region of protein coding genes

Question 7

What are microRNAs?

Answer 7

Functional, non-protein coding RNAs

22 nucleotides long; small and stable

Question 8

Describe an example of imprinting where methylation of DNA regulates gene expression?

Answer 8

Alzheimers

Neural tube defects

Question 9

What is DNA methylation?

Answer 9

Addition of a CH3 group to cytosine to form 5-methyl cytosine as part of gene regulation