(SBI4U1) DNA Structure and Replication

Question 1

What does DNA stand for?

Answer 1

Deoxyribonucleic Acid

Question 2

Where is DNA found?

Answer 2

Nucleus

Question 3

What does DNA do? (2)

Answer 3

Contains hereditary information

Provides instructions for making proteins

Question 4

Why are proteins important?

Answer 4

Needed to carry cellular processes

Question 5

What is the monomer that makes a DNA polymer?

Answer 5

Nucleotides

Question 6

What are the three parts of a nucleotide?

Answer 6

Phosphate
Pentose/ribose sugar (deoxyribose)
Nitrogen base

Question 7

What are the 4 nitrogen bases?

Answer 7

Adenine
Guanine
Thymine
Cytosine

Question 8

Identify the nitrogen base: A

Answer 8

Adenine

Question 9

Identify the nitrogen base: G

Answer 9

Guanine

Question 10

Identify the nitrogen base: T

Answer 10

Thymine

Question 11

Identify the nitrogen base: C

Answer 11

Cytosine

Question 12

Which two nitrogen bases are double rings?

Answer 12

Adenine and Guanine

Question 13

Which two nitrogen bases are single ring?

Answer 13

Thymine and Cytosine

Question 14

What are double ring nitrogen bases called?

Answer 14

Purines

Question 15

What are single ring nitrogen bases called?

Answer 15

Pyrimidines

Question 16

What is the main structural component of the DNA double helix?

Answer 16

The sugar-phosphate backbone

Question 17

The 2 sugar-phosphate backbones are bonded to each other through their ________ _____ using _________ _______

Answer 17

Nitrogen bases

Hydrogen Bonding

Question 18

A purine always pairs up with what?

Answer 18

Pyrimidine

Question 19

Adenine (A) always binds to:

Answer 19

Thymine (T)

Question 20

Cytosine (C) always binds to:

Answer 20

Guanine (G)

Question 21

DNA exhibits _______________ base pairing

Answer 21

Complementary

Question 22

The 5’ end of one sugar is connected to the _’ end of the next sugar by a __________ group

Answer 22

3

Phosphate

Question 23

The sequence/order of nitrogen bases is always read in the _’ to _’ direction

Answer 23

5’

3’

Question 24

The 2 sugar-phosphate strands are “_______” relative to each other in order to keep the nitrogen bases line up
What is this called?

Answer 24

Flipped

Antiparallel strands

Question 25

The sugar phosphate strand on the left side runs _' to _'

Answer 25

5' | 3'

Question 26

What are the three main differences between DNA and RNA?

Answer 26

The sugar molecule of DNA is missing an oxygen from carbon 2 The nitrogenous base in RNA is Uracil instead of Thymine in DNA DNA is double stranded, whereas RNA is single stranded

Question 27

When cells divide, ___ needs to be copied

Answer 27

DNA

Question 28

What enzymes make the new DNA?

Answer 28

DNA polymerases

Question 29

What is needed by DNA polymerases to build new DNA? (2)

Answer 29

Template strand | Primer

Question 30

What is a primer? (2)

Answer 30

Short strands of RNA | Starting point where new nucleotides are added to the growing strand

Question 31

DNA polymerases synthesize DNA in what direction?

Answer 31

5' to 3' direction

Question 32

On on half of the DNA, the new strand is made as a continuous piece called:

Answer 32

Leading strand

Question 33

On the other half of the DNA, the new strand is made in small pieces called:

Answer 33

Lagging strand

Question 34

What enzyme breaks the hydrogen bonds between nitrogen bases during DNA replication?

Answer 34

Helicase

Question 35

What stabilizes the single strands of DNA so that they don't rejoin?

Answer 35

Single Stranded Binding (SSB) Proteins

Question 36

Primers are a ________ point where new nucleotides are added to the _______ strand

Answer 36

Starting | Growing

Question 37

New nucleotides are added by:

Answer 37

DNA polymerase III

Question 38

Which end does the DNA polymerase III adds nucleotides?

Answer 38

Only adds nucleotides to the 3' end of an existing DNA strand

Question 39

What provides a 3' end for DNA polymerase III to add to?

Answer 39

RNA primer

Question 40

DNA polymerase III adds nucleotides in what direction?

Answer 40

5' to 3'

Question 41

On which strand can DNA polymerase add nucleotides continuously?

Answer 41

Leading strand

Question 42

What are the short DNA segments added on the lagging strand called?

Answer 42

Okazaki Fragments

Question 43

Why is there short DNA segments on the lagging strand? (2)

Answer 43

DNA can only be added in the 5' to 3' direction | The newly forming lagging strand runs 3' to 5'

Question 44

The primers of the lagging stand are _______ by what?

Answer 44

Removed | DNA polymerase I

Question 45

What are Okazaki fragments joined together by?

Answer 45

DNA ligase

Question 46

Once all RNA primers are removed, new DNA is left with _____ _____ ________ ____ that are _______

Answer 46

Short single stranded ends | Removed

Question 47

What are the short single stranded ends that are removed called?

Answer 47

Telomers

Question 48

As ________ shorten, the cell ages and eventually dies

Answer 48

Telomers

Question 49

Why are telomers removed?

Answer 49

They are removed because the ends are noncoding regions

Question 50

Is DNA replication perfect?

Answer 50

No

Question 51

What can catch errors in base pairing? How does it deal with errors?

Answer 51

DNA polymerase I | Remove incorrect bases