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Flashcards in Gene regulation in eukaryotes Deck (11):

what is the structure of chromatin?

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


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


describe features of euchromatin

lightly packed chromatin
acetyl group neutralises histones positive charge
unmethylated DNA


what is the inactive state of transcription?

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


what is the paused state of transcription?

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


what is the active state of transcription?

more transcription factors bind and RNA polymerase becomes phosphorylated


what is RNA processing?

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


what are 2 types of small RNA?

- small interfering RNA
- micro RNA


what does siRNA do?

Repression of gene transcription via chromatin remodelling and DNA methylation


what does miRNA do?

- repression of gene translation
- promotes mRNA degradation


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