Chapter 7

Question 1

what is the central dogma of molecular biology?

Answer 1

flow of genetic info from DNA to RNA to proteins

Question 2

what is transcription?

Answer 2

copy the nucleotide sequence of DNA into RNA?

Question 3

what is translation?

Answer 3

use the info in RNA to make protein

Question 4

how is ribose different from deoxyribose?

Answer 4

RNA has an additional -OH group

Question 5

what base pair does uracil form with?

Answer 5

adenine

Question 6

what does transcription produce?

Answer 6

an RNA complement to one strand of DNA

Question 7

T or F? Does the coding strand of DNA have the same sequence to the RNA product?

Answer 7

true

Question 8

the RNA chain produced by transcription is called what?

Answer 8

transcript

Question 9

what enzyme transcribes DNA?

Answer 9

RNA polymerase

Question 10

what does RNA polymerase do?

Answer 10

catalyzes the formation of the phosphodiester bonds that link the nucleotides together and form sugar-phosphate backbone of RNA

Question 11

when RNA polymerase moves along the DNA what happens?

Answer 11

unwinding the DNA helix in front of it

Question 12

what determines where bacterial RNA polymerase starts and stops transcription?

Answer 12

signals in the sequence of a gene

Question 13

bacterial RNA polymerase contains a subunit called?

Answer 13

the sigma factor

Question 14

what does the sigma factor recognize?

Answer 14

the promoter on the DNA

Question 15

once transcription begins, what happens to the sigma factor?

Answer 15

is released and the polymerase continues synthesizing the RNA without it

Question 16

how long does chain elongation continue?

Answer 16

until the polymerase encounters a termination signal in the DNA

Question 17

what happens to the polymerase after it is done transcribing?

Answer 17

the poly reassociates with the free sigma factor and searches for another promoter to start process over

Question 18

what determines the direction of transcription?

Answer 18

the orientation of the promoter at the beginning of each gene

Question 19

how many types of RNA polymerase are in eukaryotic cells?

Answer 19

3

Question 20

what does eukaryotic RNA polymerase require to start transcription?

Answer 20

the assistance of a large set of accessory proteins

Question 21

what are transcription factors?

Answer 21

they assemble at each promoter along with the polymerase before the polymerase begins transcription

Question 22

RNA polymerase II requires what for transcription initiation?

Answer 22

general transcription factors

Question 23

how is the TATA box recognized and bounded?

Answer 23

by the general transcription factor TFIID through its subunit called TATA-binding protein (TBP)

Question 24

The TATA box binding of TFIID then enables the adjacent binding of what?

Answer 24

TFIIB, one of the general transcription factors

Question 25

what comes together to form a complete transcription initiation complex?

Answer 25

TFIIH and RNA polymerase itself assemble at the promoter to form

Question 26

what does TFIIH do?

Answer 26

pries apart the double helix of DNA

Question 27

TFIIH also phosphorylates the long polypeptide tail of RNA poly II by?

Answer 27

releasing it from the general transcription factor so it can begin the elongation phase of transcription

Question 28

TATA-binding protein (TBP) binds to the TATA box sequence and distorts what?

Answer 28

DNA

Question 29

TBP is the subunit for what?

Answer 29

the general transcription factor TFIID

Question 30

what is TFIID responsible for?

Answer 30

for recognizing and binding to the TATA box sequence

Question 31

what is TBP made of?

Answer 31

a single polypeptide chain. 8 beta sheets sit atop of DNA

Question 32

phosphorylation of RNA polymerase II allows what?

Answer 32

RNA-processing proteins to assemble on its tail

Question 33

what are transcribed and processed simultaneously in the nucleus?

Answer 33

eukaryotic RNAs

Question 34

what type of modifications are made to RNA during processing?

Answer 34

capping at the 5' end with guanine, polyadenylation at the 3' ends with poly-A tail, and splicing

Question 35

why are eukaryotic genes organized differently than bacterial genes?

Answer 35

the coding sequences of most euk genes (exons) are interrupted by noncoding sequences (introns)

Question 36

what signals the beginning and the end of an intron?

Answer 36

special nucleotide sequences

Question 37

what are the special sequences recognized by?

Answer 37

by small nuclear ribonucleoprotein particles (snRNPs), which contain small nuclear RNAs (snRNAs) and proteins

Question 38

what forms the core of the spliceosome, which carries out RNA splicing?

Answer 38

snRNPs

Question 39

what does spliceosome do?

Answer 39

cleaves the RNA at the intron-exon borders and then covalent link the exons

Question 40

what does the intron form during splicing?

Answer 40

a branched strucuture

Question 41

what does a-tropomyosin protein regulates?

Answer 41

the contraction in muscle cells

Question 42

what is alternative splicing?

Answer 42

allows many different proteins to be produced from same gene

Question 43

what signals that a mature mRNA is ready for export to the cytoplasm?

Answer 43

RNA-binding proteins