Overview of General Genetic Principles Flashcards
one gene codes for at least how many different proteins?
at least 10
what is alternative splicing?
one gene encodes for multiple mRNAs
SNPs usu occur where?
more frequently occur in non-coding regions
what %age of the genome is protein coding?
4%
what %age of DNA is highly conserved?
1.5-5%
who passes on mtDNA?
female!
A=? T=? G=? C=? U=?
A = adenine T = thymine G = guanine C = cytosine U = uracil
5 point control of DNA replication?
- chromatin stage
- transcriptional stage
- translational stage
- post translational control into cytoplasm
- post translational modification
talk through double helix DNA strand up to chromosome
double helix DNA wrapped around nucleosomes to form chromatin
chromatin modules then packed together
packed chromatin makes a section of a chromosome
continued packing forms chromosome
what does 1) regulation at the chromatin stage involve?
histone methylation
histone acetylation
other types of histone modification
target sites of histone methylation in stage 1?
methylation of cytidine end result ?
target sites of histone methylation are the cytidine residues which exist as a dinucleotide (CpG)
areas rich with CpG = CpG islands
methylation of cytidine down regulates transcription
what is involved in histone acetylation?
addition of acetyl group
DNA stopped from being further condensed
active transcription thus encouraged
what is involved with “other types of histone modifications?”
addition of other groups to lysines and arginines
methylation stimulates transcription
demethylation inhibits gene transcription at that region
what are promoter regions codes?
CCATT & TATA boxes
what is involved in stage 2) regulation of transcription?
promoters
exon shuffling
enhancers
what is exon shuffilng?
removing introns btw exons to make “mature transcript”
what are enhancers?
regions where transcription factors bind so as to get DNA transcription, translation
what are the components of stage 3) regulation of RNA transport?
exportins
nuclear transport
what are exportins?
only some RNA fxn w/in the nucleus
all others have to be transported into the cytoplasm through nuclear pores –> this happens through active transport and is inhibited by controlling the attachment of exportins
what is nuclear transport?
small molecules can enter the nuclear w/o regulation but macromolecules such as RNA and proteins require assoc w/karyopherins called importins to enter the cell and exportins to exit
ability of importins and exportins to transport their “cargo” is regulated by what?
small GTPase proteins called “Ran”
what is included in stage 4) regulation of translation?
RNA processing and Cap/Tail communication
what is Cap/Tail communication?
addition of 5’ cap and addition of 3’ poly (A) tail
removal of introns (non-coding regions), splicing of exons (coding regions)
5 ways gene expression is controlled from the nucleus to the cytoplasm?
chromatin stage –> transcriptional stage –> translational stage –> post-translational control into cytoplasm –> post-translational modification
