Overview of General Genetic Principles

Question 1

one gene codes for at least how many different proteins?

Answer 1

at least 10

Question 2

what is alternative splicing?

Answer 2

one gene encodes for multiple mRNAs

Question 3

SNPs usu occur where?

Answer 3

more frequently occur in non-coding regions

Question 4

what %age of the genome is protein coding?

Answer 4

4%

Question 5

what %age of DNA is highly conserved?

Answer 5

1.5-5%

Question 6

who passes on mtDNA?

Answer 6

female!

Question 7

A=? T=? G=? C=? U=?

Answer 7

A = adenine
T = thymine
G = guanine
C = cytosine
U = uracil

Question 8

5 point control of DNA replication?

Answer 8

1. chromatin stage
2. transcriptional stage
3. translational stage
4. post translational control into cytoplasm
5. post translational modification

Question 9

talk through double helix DNA strand up to chromosome

Answer 9

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

Question 10

what does 1) regulation at the chromatin stage involve?

Answer 10

histone methylation
histone acetylation
other types of histone modification

Question 11

target sites of histone methylation in stage 1?

methylation of cytidine end result ?

Answer 11

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

Question 12

what is involved in histone acetylation?

Answer 12

addition of acetyl group
DNA stopped from being further condensed
active transcription thus encouraged

Question 13

what is involved with “other types of histone modifications?”

Answer 13

addition of other groups to lysines and arginines
methylation stimulates transcription
demethylation inhibits gene transcription at that region

Question 14

what are promoter regions codes?

Answer 14

CCATT & TATA boxes

Question 15

what is involved in stage 2) regulation of transcription?

Answer 15

promoters
exon shuffling
enhancers

Question 16

what is exon shuffilng?

Answer 16

removing introns btw exons to make “mature transcript”

Question 17

what are enhancers?

Answer 17

regions where transcription factors bind so as to get DNA transcription, translation

Question 18

what are the components of stage 3) regulation of RNA transport?

Answer 18

exportins

nuclear transport

Question 19

what are exportins?

Answer 19

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

Question 20

what is nuclear transport?

Answer 20

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

Question 21

ability of importins and exportins to transport their “cargo” is regulated by what?

Answer 21

small GTPase proteins called “Ran”

Question 22

what is included in stage 4) regulation of translation?

Answer 22

RNA processing and Cap/Tail communication

Question 23

what is Cap/Tail communication?

Answer 23

addition of 5’ cap and addition of 3’ poly (A) tail

removal of introns (non-coding regions), splicing of exons (coding regions)

Question 24

5 ways gene expression is controlled from the nucleus to the cytoplasm?

Answer 24

chromatin stage –> transcriptional stage –> translational stage –> post-translational control into cytoplasm –> post-translational modification