Development of organisms Flashcards
transcription factor
protein that binds to the DNA in the nucleus and affects the process of transcribing DNA into RNA
promoter sequence
specific region on the DNA to which transcription factors bind to stimulate transcription
enhancer sequence
specific region of DNA to which transcription factors bind and regulate the activity of the DNA by changing the structure of chromatin
exons
segments of a DNA or RNA molecule containing information coding for a protein or peptide sequence
introns
segments of a DNA or RNA molecule containing information which does not code for a protein or peptide sequence
pre-mRNA
mRNA that is transcribed directly from the DNA before it has been modified
Spliceosomes
enzyme complexes that act on pre-mRNA, joining exons together after the removal of the introns
DNA methylation
methylation of DNA (addition of a methyl-CH3 group) to a cytosine in the DNA molecule next to a guanine in the DNA chain and prevents the transcription of a gene
DNA demthylation
removal of a methyl group from methylated DNA enabling genes to become active so they can be transcribed
heterochromatin
densely supercoiled and condensed chromatin where the genes are not available to be copied or make proteins
histone acetylation
additions of an acetyl group (-COCH3) to one of the lysines in the histone structure, which opens up the structure and activates the chromatin, allowing genes in that area to be transcribed
histone methylation
addition of a methyl group (-CH3) to a lysine in the histone; methylation may cause inactivation or activation of the region of DNA, depending on the position of the lysine
non-coding RNA (ncRNA)
98% of the RNA, which does not code for proteins but affects the transcription of the DNA code, modifies the chromatin structure or modifies the products of transcription
