transcription

Question 1

reverse transcriptase

Answer 1

RNA-dependent DNA polymerase. enzyme that generates complementary DNA from an RNA template, It is mainly associated with retroviruses. (HIV)

Question 2

RNA polymerase:

Answer 2

DNA dependent RNA polymerase. uses a DNA template to make RNA

Question 3

DNA polymerase

Answer 3

DNA dependent polymerase. needs a DNA template to make DNA

Question 4

central dogma

Answer 4

DNA->RNA->proteins

Question 5

T/f: RNA polymerase has editing function

Answer 5

false

Question 6

which type of rna is involved in coding genes

Answer 6

mRNA

Question 7

do mitochondria and chloroplasts have the same set of RNA polymerases as regular cells?

Answer 7

no. they have their own.

• Not coded for in nucleus.
• Makes sense in light of endosymbiotic theory.

Question 8

describe prokaryotic RNA polymerase?

Answer 8

• have only a single type of RNA polymerase. Closely related to one found in mito, chloroplasts.

Question 9

what tells RNA polymerase where to begin transcription?

Answer 9

promoter sequence

Question 10

what tells RNA polymerase to stop making RNA?

Answer 10

termination signal

Question 11

small factor in bacteria called ___that helps RNA polymerase recognize promoter sequence that it needs to get starteds and run ‘de novo’ after starting

Answer 11

sigma factor

Question 12

what’s interesting about the 5’ end of the newly synthesized strand of RNA?

Answer 12

5’ end of this RNA has 3 phosphates on it- as no nucleotide is attached to it

Question 13

in what kind of organism would you find a ta ta box?

Answer 13

prokaryotes

Question 14

what would you find in the promoter region of prokarytoes?

Answer 14

• -10 sequence ( ‘ta-ta box’)
• -35 sequence. (not all have this, but most do.) These are called consensus sequences.

Question 15

consensus sequences

Answer 15

10’, 35’ sequences at promoter region of prokaryotic DNA

Question 16

Promotor region

Answer 16

• a sequence of DNA that tells the RNA polymerase where to sit down to begin transcription

Question 17

Rho protein termination

Answer 17

Rho protein jumps on if it sees a rho sequence, twists itself, breaks it away from polymerase to end transcription. ‘rho dependent termination

Question 18

. Hairpin/Rho independent termination- what is it and where does it occur?

Answer 18

prokaryotes- stops transcription. sees some sort of complementary regions, folds so those regions pair. That causes the transcription to stop

Question 19

what does it mean when we say direction of transcription is determined by orientation of promoter

Answer 19

Transcription is asymmetric, i.e. each gene is transcribed in only one direction such that if the lower strand serves as the template (e.g. gene C), then the upper strand will not be a template for other transcription . it goes in whatever way the promoter sequence is facing.

Question 20

polycistronic transcripts and where you would find them

Answer 20

coding for more than one gene in a single transcript . prokaryotes.

Question 21

looking at this photo- where is the promoter region?

Answer 21

far left of each blob.

shortest = at start. Longer strands = happening later. Little black dots are rna polymerase

Question 22

pro or euk mRNA: has a methyl guanine added on to 5’ end . ‘5’ cap’ added on in order to protect the RNA from the enzymes so they can’t chew it up

Answer 22

eukaryotic

Question 23

what do we mean when we say Eukaryotic mRNA has modifications at ends

Answer 23

5’ cap and tons of A’s (adenylation) at 3’ end

Question 24

how many genes do eukaryotic mRNA transcripts contain information for

Answer 24

just one

Question 25

Exons and introns

Answer 25

Exons are expressed sections. Introns are sections of noncoding regions- not expressed.

Question 26

do bacteria have exons/introns?

Answer 26

no

Question 27

examples of introns and exons in real genes

Answer 27

* Beta globin: 3 exons 2 introns. VIII gene: clotting factor for hemophilia: 26 exons, 25 introns

Question 28

mature mRNA

Answer 28

mRNA with all introns removed- 'ready to go'

Question 29

what are the 2 modifications eukaryotes make to mRNA

Answer 29

capping , adenylation

Question 30

Rna splicing

Answer 30

specifically removes introns from RNA. (happens in nucleus) to produce the mature mRNA

Question 31

snRNP’s

Answer 31

SNRPS perform RNA splicing splicers gon splice.

Question 32

how do SNRP's splice?

Answer 32

* Form base pairs with 5’ end of intron and 3’d end of intron * Always an A nucleotide in there * Pull the 2 sections together. Bend it around and attach it to the A. ‘lariat’ like a lasso rope appearance. Cut off 3’ end of intron, hook ends of exons together. Throw away the intron lasso thing. Happening at every intron/exon junction.

Question 33

How can we do everything we do with only 23,000 genes?

Answer 33

alternative splicing

Question 34

\_\_\_can generate multiple proteins from transcripts from a single gene

Answer 34

Alternative splicing

Question 35

where is prokaryotic RNA translated

Answer 35

out in the cytoplasm- no nucleus!

Question 36

describe the process that has to occur before eukaryotic mRNA can be translated

Answer 36

* nuleus surrounding all DNA: Transcribe in nucleus. Then cap. Then polyadenalate. Then splice out introns. All that to get a mature mRNA. Then ship to cytoplasm. Then and only then translation begins.

Question 37

Translation:

Answer 37

process of using sequence in mRNA to code for a protein.

Question 38

transfer rna’s

Answer 38

little short rna’s 100 nucleotides long that have job of bringing amino acids to the site of translation, where proteins are being made

Question 39

anticodon region of tRNA

Answer 39

a sequence of three bases in **tranfer** RNA that are complementary to a codon in the **messenger** RNA

Question 40

\_\_\_end of tRNA is where amino acid attaches

Answer 40

3'

Question 41

tRNA synthetase

Answer 41

charges tRNA's aka Puts amino acids onto them

Question 42

tRNA synthase enzyme takes an amino acid and hooks ___ terminus onto \_\_\_end of tRNA. gets the energy from:

Answer 42

COOH , 3' * Uses an ATP to generate a high energy bond. Here we convert ATP to AMP- break off TWO phosphate.