7. Molecular Genetics

Question 1

DNA goes from

Answer 1

5’ to 3’

Question 2

replication

Answer 2

helicase unwinds dna forming a replication fork

• SSBs keep it open
• Topoisomerase decreases tension
• DNA pol moves from 3’ to 5’ making strand
• makes the lagging strand using primase fragments (DNA ligase connects and then DNA pol I changes to DNA)

Question 3

DNA pol functions

Answer 3

pol 3 replicates but can also check via exonuclease

- pol I breaks down fragments

Question 4

telomere replication

Answer 4

telomerase adds elongation to end so it doesn’t degrade

Question 5

protein synthesis

Answer 5

• AA’s are redundant
• mRNA has 64 possible codons
• tRNA has a clover shape with h bonds (tiny abundance)
• rRNA (rich abundance) is the DNA being transcribed with the mRNA (merger abundance) bound as well as the tRNA

Question 6

transcription

Answer 6

• RNA pol binds to promoter region (in eukaryote is tata box, prokarya is Pribnow box)
• only one strand is transcribed, which is the temple antisense DNA trand, while the other is the CODing/ sense strand
• AAA coding strand is end

Question 7

rna has greater error than

Answer 7

dna

Question 8

mRNA processing

Answer 8

5’ cap, poly a tail, introns spliced out

Question 9

translation

Answer 9

• GTP as energy
• small ribosome attaches to 5’ end, MET attaches to AUG
• elongation then A site releases MET in E site. this then moves in translocation.
• termination is reaching stop codon UAG, UAA, UGA
• folding using chaperone proteins

Question 10

post translation

Answer 10

may go to ER and secreted via Golgi

Question 11

multiple ribosomes can attackh in

Answer 11

prokarya

Question 12

bacteria start codon

Answer 12

formylmethionine

Question 13

silent mutation

Answer 13

same codon

Question 14

nonsense

Answer 14

new codon is stop codon

Question 15

missense

Answer 15

codon is new amino acid

Question 16

proofreading mech

Answer 16

• dna pol, mismatch repair for mismatched bases, or excision repair where damaged dna goes away (T dimers)

Question 17

nucelosome

Answer 17

DNA around 8 bundles of histones

Question 18

euchromatin

Answer 18

loosely bound dna to be transcribed

Question 19

heterochromatin

Answer 19

tight DNA no transcribe

Question 20

transposons

Answer 20

dna segments that jump around

Question 21

pseudo genes

Answer 21

no longer code for anything

Question 22

virus

Answer 22

DNA or RNA with protein capsid coat made from capsomeres and viral envelope (protein from host if it has one)

Question 23

lytic cycle

Answer 23

virus penetrates host and then hijacks it to make new virus, then explode out of cell and infect other cells

Question 24

DNA virus

Answer 24

dna forms new viral dna

Question 25

rna virus

Answer 25

rna serves as mNA that is made into a protein

Question 26

retrovirus

Answer 26

use reverse transcriptase to make DNA complete their na, which goes to lysogenic cycle

Question 27

lysogenic

Answer 27

viral DNA is incorporated into DNA of host cell. can be dormant (provirus or prophage)

Question 28

prions

Answer 28

misfolded proteins that cause others to misfold

Question 29

viroids

Answer 29

smaller than virus RNA that infect plants

Question 30

binary fission

Answer 30

chromosome replicates, cell divides (bacteria!)

Question 31

plasmids

Answer 31

short dna that is outside chromosome (not essential)

Question 32

episomes

Answer 32

plasmids that incorporate into bacterial chromosome

Question 33

conjugation

Answer 33

donor produces pills, connects ot recipient, sends chromosome and then it recombines.

Question 34

transduction

Answer 34

DNA is given by virus. done in lytic cycle when bacterial dna goes in place of viral dna

Question 35

operon in prokaryotes

Answer 35

has 1. promoterL RNA pol attaches 2. operator: region that blocks rna pol 3. genes: DNA 4. regulatory genes: produce repressor or activator proteins that affect promoter region

Question 36

lac operon

Answer 36

breakdown of glucose. when lactose available, lactose removes repressor and now can make enzyme.

Question 37

low glucose is cAMP?

Answer 37

high cAMP levels

Question 38

cAMP?

Answer 38

binds to cap binding site of promoter region. and thus gives better transcription

Question 39

if lactose and glucose are high

Answer 39

then no operon production for lactase. body prefers glucose digestion

Question 40

typ operon

Answer 40

enzyme for tryptophan synth. tryptophan itself binds to activate repressor, and blocks rna pol

Question 41

repressible enzymes

Answer 41

when genes sto[ making enzymes in presence of an active repressor

Question 42

constitutive genes

Answer 42

constantly expressed

Question 43

regulation allowing cell specific stuff

Answer 43

using activators can make different cells by turning off certain segments

Question 44

methylation of histores

Answer 44

tighter packing so no transcription

Question 45

acetylation

Answer 45

uncoiling of chromosomes so transcription proceeds

Question 46

RNA interference

Answer 46

micro and short interfering (miRNA or siRNA) RNA can block translation too. * RNA interference is specifically siRNA blocking