Ch 12 Dna Replication

Front 1

DNA - held together by what kind of bond?

Back 1

hydrogen bonds

Front 2

A and T are held together by how many hydrogen bonds?

Back 2

two

Front 3

G and C are held together by how many hydrogen bonds

Back 3

three

Front 4

Duplication of DNA molecule occurs in which phase in the cell cycle

Back 4

S phase

Front 5

Semiconcervative Replication

Back 5

During replication the two strands of parental duplex separate. Each parental strand serves as a template for the synthesis of a new daughter strand, using the base-pairing rules of A with T and G with C

Front 6

Result of semiconservative Replication

Back 6

two strands will be duplicated exactly

Front 7

definition of semiconservative

Back 7

each daughter DNA molecule each made up of one parental strand and one new strand.
visual -
two strands together.
these two strands separate.
one of these separated strands is paired with another strand. therefore, in this NEW pair there is one parental strand paired with a new strand.
the other strand from the original parent molecule, does the same.
the new strand is called "daughter" DNA molecule

Front 8

where does DNA replication begin?

Back 8

replication begins simultaneously at many origins of replication = specific sequence of nucleotides

Front 9

what occurs in the origin sites?

Back 9

the DNA strand separate forming a replication bubble and replication forks at each end

Front 10

replication forks

Back 10

found at the end of the replication bubble at the origins of replication when the DNA is initially replicated

Front 11

in which replication does replication proceed while the molecule is being copied?

Back 11

both directions

Front 12

bidirectional replication

Back 12

replication proceeds in both direction until the entire molecule is copied

Front 13

Eukaryotic chromosomes: at each replication fork, which end of the new strand becomes the leading strand?

Back 13

3' end

Front 14

Eukaryotic chromosomes: leading strand

Back 14

at each replication fork, the new strand with free 3' end

Front 15

Eukaryotic chromosomes: at the replication fork, which end of the new strand consist of the lagging strand

Back 15

5'

Front 16

Eukaryotic chromosomes: when two replication bubbles meet , they fuse to make a smaller or larger bubble?

Back 16

larger bubble

Front 17

Prokaryotic chromosome: what shape is their chromosome

Back 17

circular

Front 18

Prokaryotic chromosome where does replication start?

Back 18

starts at the origin of replication

Front 19

Prokaryotic chromosome

Back 19

since it is circular, it is like two elastic bands and one being peeled off.

Front 20

helicases

Back 20

untwist and separate parental strands at replication fork

Front 21

single-stranded binding proteins (SSBs)

Back 21

stabilize separated strands

Front 22

Topoisomerase II

Back 22

relieves strain ahead of replication fork due to untwisting

Front 23

RNA primase

Back 23

synthesizes RNA primers to initiate new DNA strand

Front 24

DNA polymerases

Back 24

extend the RNA primer (5-10 nucleotides with free 3' OH); removes primer and replaces it with DNA

Front 25

DNA ligase

Back 25

joins the DNA fragments

Front 26

DNA polymerases can only add nucleotides to which end of an exisiting nucleotide chain

Back 26

3/

Front 27

RNA primase

Back 27

the enzyme that makes the primer in the initial steps of synthesizing a new DNA strand

Front 28

what does RNA primase synthesize?

Back 28

a short piece of RNA complementary to the DNA template

Front 29

All new DNA strands have a short stretch of RNA at which end?

Back 29

5' END

Front 30

The leading strand has it's 3' end pointing to what?

Back 30

the replication fork

Front 31

how many primers does a leading strand have?

Back 31

one

Front 32

okazaki fragments

Back 32

the lagging has it's 3' end pointed away from the replication and is synthesized in short bits called okazaki fragments

Front 33

how many primers do lagging strands have?

Back 33

many

Front 34

DNA polymerase can only synthesize DNA from which to which end?

Back 34

5' to 3'

Front 35

Synthesis of both strands must happen in the direction of what?

Back 35

of the replication fork .. the direction of replication

Front 36

How can the DNA polymerase synthesize the lagging strand 5' to 3'?

Back 36

The only way DNA polymerase can synthesize the botom (lagging) strand 5' to 3' is by making a short fragment, backing up and making a new one. These fragments are called okazaki fragments

Front 37

What are the short fragments that back up the new one.. they are the only way DNA polymerase can synthesize the lagging strand

Back 37

okazaki fragments

Front 38

Primers are required for only the leading strand and not the lagging strand. True or False

Back 38

False the primers are required for both the leading and the lagging strand

Front 39

How many primer does the leading strand need?

Back 39

The leading strand only needs one primer

Front 40

The lagging strand has how many primer?

Back 40

multiple primers and multiple okazaki fragments not joined together

Front 41

Extending the Primer: Once the primer(s) synthesized, DNA polymerase elongates the primer. How are nucleotides added on?

Back 41

LOOK UP.

Front 42

Extending the primer: hydrolysis of pyrophosphate into two inorganic phosphates is what type of reaction?

Back 42

coupled exergonic reaction

Front 43

Extending the Primer: hydrolysis of pyrophosphate into two inorganic phosphates is a coupled exergonic reaction that drives what reaction?

Back 43

polymerization reaction

Front 44

Extending the Primer: DNA polymerase

Back 44

enzyme that catalyzes the reaction

Front 45

Extending the Primer: On the leading strand DNA keeps adding ___ continously

Back 45

nucleotides

Front 46

Extending the Primer: The lagging strand is synthesized in ___ fragments

Back 46

Okazaki

Front 47

Extending the Primer: when DNA polymerase encounters primer of adjacent Okazaki fragment, what happens?

Back 47

it falls off

Front 48

Extending the Primer: what does the DNA ligase do?

Back 48

links the DNA fragments together

Front 49

Cleavage Function

Back 49

If improper hydrogen bonds form (i.e. if wrong base inserted) DNA polymerase detects the mispairing by activating a cleavage function

Front 50

How does the DNA polymerase do with regards to cleavage function

Back 50

cleavage function removes the incorrect nucleotide and inserts the correct one in its place

Front 51

What happens when there is an incorrect nucleotide added?

Back 51

When this happens, the proofreading function of DNA polymerase removes the incorrect nucleotide. Then the correct nucleotide is added to replace the incorrect one

Front 52

What does a telomere do/

Back 52

Each end of a eukaryotic chromosomes is capped by a repeating sequence called the telomere in order to solve the problems of shortened ends that occur as a lagging strand problem.

Front 53

True or False. The repeating sequences of bases in telomeres don't code for proteins.

Back 53

True

Front 54

What do telomeres protect?

Back 54

They protect the genetic information on the ends of linear chromosomes from being lost

Front 55

Exact definition of telomerase in eukaryotic DNA replication

Back 55

an enzyme containing RNA template used to lengthen the template strand, which allows replication of functional part of daughter strand to be completed