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B.6(A) explain the importance of the cell cycle to the growth of organisms, including an overview of the stages of the cell cycle and deoxyribonucleic acid (DNA) replication models

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RELATE: Watch the Amoeba Sisters video on DNA replication to find out about the specifics of what's going on in S phase.

Pay close attention to the names and functions of each enzyme!
Question 1
1.

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Question 2
2.

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There's a lot of vocabulary involved in DNA replication!

So, let's see how it might look when it's put all together in a clean, detailed animation. Watch the video and keep in mind all the vocabulary that we just reviewed (plus try to notice the one new enzyme).
Question 3
3.

Question 4
4.

Question 5
5.

Click on the area where helicase would be located:

Question 6
6.

Click on the area where primase would be located:

Question 7
7.

Click on the area where DNA polymerase would be located:

Question 8
8.

Click on the area where topoisomerase would be located:

DEEPEN: Let's see how the concepts and steps behind replication get used in a real-world example of biotechnology.
Take a look at the next slide and the following video for an example of polymerase chain reaction (PCR).
Note that denaturation here is not the same thing as enzyme denaturation from your past lesson on enzymes. This one refers to how DNA is broken apart by high heat.
Question 9
9.

EXIT:

ATTENTION:

YOU WILL USE THE ANSWERS FROM MULTIPLE CHOICE QUESTIONS 10-13.
TO ANSWER THE FOUR (4) MULTIPLE CHOICE QUESTIONS IN CANVAS IN
"B.6(A) DNA Replication Review"
Each question must be correct on Canvas to receive full credit.
Question 10
10.

Question 11
11.

Question 12
12.

Question 13
13.

BEFORE YOU SUBMIT YOUR FORMATIVE: READ THIS!

YOU WILL USE THE ANSWERS FROM MULTIPLE CHOICE QUESTIONS 10-13 IN THIS FORMATIVE.
TO ANSWER THE FOUR (4) MULTIPLE CHOICE QUESTIONS IN CANVAS IN
"B.6(A) DNA Replication Review"
Each question must be correct on canvas to receive full credit.
Match the name of each enzyme with its function.
ligase
opens up the DNA, separating the two strands by breaking the hydrogen bonds between their bases
primase
replicates DNA molecules to make a new complementary strand
topoisomerase
lays down RNA primers which allow DNA polymerase to bind to the DNA
DNA polymerase
seals the DNA together after replication
helicase
prevents DNA ahead of the helicase from supercoiling
Match the replication terms with their definition.
lagging strand
the position on DNA where replication begins
semi-conservative
special proteins that bind onto the separated DNA strands to ensure they don't come back together
leading strand
short pieces of RNA that allow DNA polymerase to bind to the separated DNA strands
Okazaki fragments
the two DNA strands run in opposite directions: one from 5' to 3' and the other from 3' to 5'
Single-Stranded Binding Proteins (SSBs)
the new DNA strand that DNA polymerase is continuously synthesizing
primers
the new DNA strand that DNA polymerase is discontinuously synthesizing
origin
DNA fragments formed due to discontinuous DNA synthesis
antiparallel
after replication is complete, both DNA molecules have one old strand and one new strand.
What is the function of the enzyme exonuclease?
replicates DNA molecules to make a new complementary strand
removes RNA primers put down by primase
seals the DNA together after replication
removes DNA primers put down by ligase
What additional step was involved in this animation besides the function of exonuclease?
DNA polymerase filling in the gaps after primers are removed
Helicase re-zipping the old DNA strands together
Ligase filling in the gaps between Okazaki fragments
DNA polymerase filling in the gaps after SSBs are removed
Categorize each enzyme and/or PCR process according to their function in DNA replication.
Taq polymerase + heating to 72 degrees C
DNA polymerase
helicase
heating to 95 degrees C
primase
cooling to 55 degrees C
ligase
Synthesizes new DNA
Breaks apart DNA strands
Attaches primers
Seals DNA together after replication
Think of all the enzymes involved in DNA replication. If ligase were to be removed from a cell, what would happen?
The two DNA strands would supercoil and prevent replication.
Newly-synthesized DNA would not hold together and would break apart.
The replication fork would not form.
DNA could not be synthesized.
Compare the DNA strands replicated in PCR to the replication fork from natural DNA replication. Why does PCR not have Okazaki fragments?

Okazaki fragments only form on a leading strand, which PCR does not have.
Okazaki fragments only form on a lagging strand, which PCR does not have.
Okazaki fragments require ligase to form, which PCR does not use.
Okazaki fragments do get formed during PCR.
What might cause the separate DNA strands in a replication fork to snap back together and end replication early?
a lack of RNA primers
denaturation of topoisomerase
failure of SSB proteins to attach to the DNA strands
exonuclease becoming unattached from the RNA primers
Recall that all of these enzymes and steps occur in the S phase of the cell cycle. If it weren't for DNA replication, what might happen to dividing cells during mitosis?
The sister chromatids would not separate correctly during anaphase.
There would be too much DNA given to the daughter cell.
The chromosomes would not line up properly during metaphase.
Nothing; without DNA replication the cell would not be allowed to proceed to mitosis at all due to the G2 checkpoint.