Gene regulation in eukaryotes Flashcards Preview

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Flashcards in Gene regulation in eukaryotes Deck (11):
1

what is the structure of chromatin?

DNA wrapped around histones and joined together to form nucleosomes which join together to from chromatin

2

describe features of heterochromatin

amino acids in histones give off positive charge so the negatively charged DNA tightly binds making it inaccessible for transcription
methylated DNA

3

describe features of euchromatin

lightly packed chromatin
acetyl group neutralises histones positive charge
unmethylated DNA

4

what is the inactive state of transcription?

RNA polymerase isn't bound to the tightly packed chromatin - no phosphorylation

5

what is the paused state of transcription?

RNA polymerase and transcription factors are bound to promotor but remain inactive - single phosphorylation

6

what is the active state of transcription?

more transcription factors bind and RNA polymerase becomes phosphorylated

7

what is RNA processing?

the addition of caps turns pre-mRNA into mature mRNA and introns are spliced out

8

what are 2 types of small RNA?

- small interfering RNA
- micro RNA

9

what does siRNA do?

Repression of gene transcription via chromatin remodelling and DNA methylation

10

what does miRNA do?

- repression of gene translation
- promotes mRNA degradation

11

describe the process of protein degradation?

- ubiquitin molecules attach to a protein
- proteasome responds and unfolds the protein
- enzymes cut the protein into small peptides which cam be further degraded by other enzymes in the cytosol