Micro Ch 7.2 (Exam 3)

Front 1

DNA synthesis begins at a unique location called

Back 1

origin of replication

Front 2

the double helix of DNA is unwound by _____, large ATP-dependent enzyme proteins.

Back 2

helicases

Front 3

as the double helix is unwound, the DNA is stabilized by a

Back 3

single-stranded binding protein

Front 4

extensions of DNA occurs ____ on the leading strand and _____ on the lagging strand

Back 4

continuously, discontinuously

Front 5

most errors in base pairing are corrected by ____ functions associated with the action of ____

Back 5

proofreading functions, DNA polymerase I and III

Front 6

enzyme that seals "cracks" in DNA replication on the lagging strand

Back 6

DNA ligase

Front 7

site of replication that appears to move down the DNA

Back 7

replication fork

Front 8

why is proofreading important to the cell?

Back 8

if there is a mispairing of bases, the base pair will be unstable

Front 9

why are there leading and lagging strands?

Back 9

because of the 5' > 3' direction that DNA must replicate in. since the parent strands are antiparallel, the new strands will be forming in different directions. one has to go "against the current".

Front 10

RNA polymerase stops transcription at specific sites called

Back 10

transcription terminators

Front 11

although encoded by ___, transcription terminators function at the level of ___

Back 11

DNA, RNA

Front 12

some transcription terminators are ______ and require no accessory proteins beyond the polymerase

Back 12

intrinsic terminators

Front 13

In bacteria, trancription terminators are often ____ followed by a run of Uracils

Back 13

stem-loops

Front 14

what is an intrinsic terminator?

Back 14

termination sites that require no accessory proteins or extra factors. usually has a G-C rich sequence followed by an A-T rich sequence which leads to termination

Front 15

what is a stem-loop structure?

Back 15

inverted repeats with central nonrepeating segment strand folds into a loop, pairing up the inverted repeating parts

Front 16

In bacteria, promoters are recognized by the _____ of RNA polymerase

Back 16

sigma subunit

Front 17

promoters recognized by a specific sigma factor have ____ sequences

Back 17

very similar

Front 18

in the eukarya, the major classes of RNA are transcribed by ____ RNA polymerases

Back 18

different

Front 19

What is a consensus sequence?

Back 19

the bases that occur most often in a particular position determine the consensus sequence

Front 20

in a eukaryote, which type of RNA polymerase transcribes genes that encode proteins?

Back 20

RNA polymerase II

Front 21

RNA polymerase that synthesizes most types of rRNA

Back 21

RNA polymerase I

Front 22

RNA polymerase that synthesizes all the mRNA

Back 22

RNA polymerase II

Front 23

RNA polymerase that synthesizes tRNA, and on type of rRNA

Back 23

RNA polymerase III

Front 24

the three major types of RNA are:

Back 24

messenger RNA, transfer RNA, and ribosomal RNA

Front 25

the transcription of RNA from the DNA involves the enzyme ____, which adds bases onto 3' ends of growing chains

Back 25

RNA polymerase

Front 26

unlike DNA polymerase, RNA polymerase can

Back 26

start a chain

Front 27

RNA polymerase recognizes a specific start site on the DNA called the

Back 27

promoter

Front 28

RNA synthesis stops at the

Back 28

transcription terminator

Front 29

what is a promotor?

Back 29

sites on DNA strands where RNA polymerase binds to begin a new chain

Front 30

what is a transcription terminator?

Back 30

a site at which trancription of RNA ends and the DNA closes into the original double helix

Front 31

The unit of transcription often contains ____ gene

Back 31

more than one

Front 32

transcription of several genes into a single mRNA molecule may occur in ____, so the mRNA may contain the information for more than one ____.

Back 32

prokaryotes, polypeptide

Front 33

genes that are transcribed together from a single promoter constitute an

Back 33

operon

Front 34

genes encoding ribosomal RNA are _____ in both prokaryotes and eukaryoes

Back 34

cotranscribed

Front 35

what is messenger RNA?

Back 35

an intermediary to the genes that encode proteins

Front 36

what is polycistronic mRNA?

Back 36

a single mRNA molecule that codes for a group of related enzymes all transcribed simulataneously.