Ch 4-6 Britton Cell Bio Notecard

Front 1

nucleoside

Back 1

a molecule consisting of the sugar and base

Front 2

what acts as substrates for DNA synthesis

Back 2

only the nucleoside triphosphates

Front 3

phosphodiester bond

Back 3

link individual nucleotides into a polynucleotide between their 5’ and 3’ ends, removes two outer phosphates (beta and gamma phosphates) from one nucleotide and the 3’ OH from another

Front 4

use for the minor groove

Back 4

histones prefer to have AT rich minor grooves positioned towards the histones

Front 5

nucleosomes

Back 5

repeat every 200 bp with a 80 bp linker region between the nucleosomes

Front 6

nuclease hypersensitive regions

Back 6

regions that are resistant to histone binding, generally associated with gene regulatory proteins

Front 7

H1

Back 7

if binds to the chromatin structure can actually make it more tightly packed

Front 8

genes and chromosomal genetic material in different cell types

Back 8

different cell types have and express different genes but have the same chromosomal genetic material

Front 9

RNAse H

Back 9

erases the RNA primer

Front 10

single strand DNA binding protein

Back 10

prevents single strands from forming hairpins

Front 11

DNA primase

Back 11

lays down a RNA primer for DNA replication to occur, produce it de novo without a free 3’ OH, but 1 error in every 10^4 incorporations

Front 12

transitions

Back 12

purine-to-purine or pyrimidine-to-pyrimidine changes

Front 13

transversions

Back 13

purine to pyrimidine or vice versa

Front 14

direct repair

Back 14

act directly on damaged nucleotides, converting each one back to its original structure

Front 15

excision repair

Back 15

involves excision of a segment of the polynucleotide containing a damaged site, followed by resynthesis of the correct nucleotide sequence by a DNA polymerase

Front 16

mismatch repair

Back 16

corrects errors of replication (ie. mismatches), again by excising a stretch of single-stranded DNA containing the offending nucleotide and then repairing the resulting gap

Front 17

recombination repair

Back 17

used to mend double stranded breaks

Front 18

why recombination

Back 18

provides variability without fidelity, meiosis, allows for traits and alleles to propagate

Front 19

general recombination

Back 19

based on homology, occurs during meiosis (crossing over), and occurs over long stretches of DNA

Front 20

site specific recombination

Back 20

need not have any homology, can occur at any time, and occurs at short, specific DNA nucleotides

Front 21

transcriptome

Back 21

initial product of genome expression, a collection of RNA molecules from protein-coding genes

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proteome

Back 22

cell’s repertoire of proteins

Front 23

genome expression steps

Back 23

1. accessing the genome
2. assembly of the transcription initiation complex (must be adjacent to the active genes, nowhere else)
3. synthesis of RNA
4. processing of RNA
5. RNA degradation
6. assembly of the translation initiation complex
7. protein synthesis
8. protein folding and protein processing
9. protein degradation

Front 24

mRNA

Back 24

short lived, degraded soon after synthesis, only 2-4% of the total RNA

Front 25

rRNA

Back 25

most abundant RNA (80%)

Front 26

small cytoplasmic RNA (scRNA)

Back 26

a diverse group with a range of functions

Front 27

MicroRNAs (miRNAs)

Back 27

are a family of ~21-25 nucleotide small RNAs that negatively regulate gene expression at the post-transcriptional level

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promoters

Back 28

only found upstream of genes

Front 29

what signals the poly-A tail

Back 29

signal sequence in the mRNA (AAUAAA), cleaved at an internal site and poly-A tail is added

Front 30

three stages in translation

Back 30

1. initiation
2. elongation
3. termination

Front 31

how do ribosomes recognize mRNAs

Back 31

5’ cap