DNA Replication

Question 1

Nucleic Acids

Answer 1

Macromolecules that encode genetic material and direct gene expression

Question 2

2 nucleic acids used by human cells

Answer 2

DNA and RNA

Question 3

What are the monomers of nucleic acids?

Answer 3

Nucleotides

Question 4

3 parts of nucleotides

Answer 4

Phosphate
Sugar
Base

Question 5

Pentose sugar

Answer 5

Sugar used in DNA and RNA
Contains 5 carbons

Question 6

Sugar used in DNA

Answer 6

Deoxyribose

Question 7

Sugar used in RNA

Answer 7

Ribose

Question 8

Difference between deoxyribose and ribose

Answer 8

Ribose has OH on carbon 2
Deoxy has H on carbon 2

Question 9

Phosphodiester bond

Answer 9

C5 of each sugar bonds to phosphate molecule, and can react with OH group on C3 of another nucleotide sugar

Question 10

What does a phosphodiester bond result in?

Answer 10

Sugar-phosphate backbone of DNA

Question 11

4 DNA bases

Answer 11

Adenine
Thymine
Cytosine
Guanine

Question 12

Primary Structure

Answer 12

Sequence of nucleotide bases in a single strand of nucleic acid

Question 13

2 types bases can be divided into

Answer 13

Purines
Pyrimidines

Question 14

Purines

Answer 14

Large bases
Contain 2 rings

Adenine and Guanine

Question 15

Pyrimidines

Answer 15

Smaller bases
Contain only 1 ring

Thymine and cytosine

Question 16

Complementary base pairing

Answer 16

Bases of 1 DNA strand bond to bases of another strand
Each base can only bond with its pairing

Purine must always bond to a Pyrimidine

Question 17

Hydrogen bonds

Answer 17

Types of bonds formed between bases
Hydrogen atom of 1 base is attracted to nitrogen/oxygen atom of another base

Question 18

Are hydrogen bonds stronger or weaker than ionic/covalent bonds?

Answer 18

Weaker (allows bonds to break with ease)

Question 19

What bases form 2 hydrogen bonds

Answer 19

Adenine and thymine

Question 20

What bases form 3 hydrogen bonds

Answer 20

Cytosine and guanine

Question 21

What’s the secondary structure of DNA?

Answer 21

Complementary base pairing

Question 22

Antiparallel

Answer 22

Sugar phosphate backbones face opposite directions

Question 23

Is sugar phosphate backbone hydrophilic or hydrophobic?

Answer 23

Hydrophilic

Question 24

Are bases hydrophobic or hydrophilic?

Answer 24

Hydrophobic

Question 25

Minor groove

Answer 25

Smallest groove within helix of DNA Occurs where overlapping backbones are closest together

Question 26

Major groove

Answer 26

Occurs where gap btw backbones is greatest Allows easy access for protein attachment

Question 27

Supercoiling

Answer 27

DNA attaches to histone proteins and spools up DNA like fishing rod to keep it compact in nucleus

Question 28

Chromatin

Answer 28

Combination of DNA and histone

Question 29

What is the 4th structure of DNA

Answer 29

Chromatin

Question 30

3 steps in DNA replication

Answer 30

Initiation Elongation Terminator

Question 31

What does DNA replication require?

Answer 31

Pre existing DNA Free nucleotides Enzymes

Question 32

Initiation and what does it involve

Answer 32

First step of DNA replication Involves unwinding of double helix and breaking of hydrogen bonds

Question 33

What does topoisomerase do?

Answer 33

Unwinds double helix of DNA exposing nucleotide bases making it easier for enzymes to attach

Question 34

Helicase

Answer 34

Enzyme that breaks apart hydrogen bonds, separating the 2 strands

Question 35

Where does helicase attach to?

Answer 35

Origins of replication once helicase has unzipped strands

Question 36

Primers

Answer 36

Short sequence of RNA that serve as starting point for DNA synthesis

Question 37

Elongation

Answer 37

Second stage in DNA replication New DNA strands are synthesized

Question 38

Semi conservative

Answer 38

Resulting DNA is a combination of parent strands and daughter strands

Question 39

How do free nucleotides temporarily attach to open DNA strands?

Answer 39

Hydrogen Bonding

Question 40

How does DNA polymerase synthesize daughter strands?

Answer 40

Fuses nucleotides together via sugar phosphate backbone

Question 41

Replication fork

Answer 41

Opening in DNA behind helicase

Question 42

Leading strand

Answer 42

Daughter strand in replication fork being synthesized in 5’ to 3’ direction

Question 43

Lagging strand

Answer 43

Daughter strand in replication fork being synthesized in 3’ to 5’ direction

Question 44

Okazaki fragments

Answer 44

Short sequences of lagging strand DNA

Question 45

What enzyme is used to fuse Okazaki fragments together?

Answer 45

Ligase

Question 46

What’s another job of DNA polymerase?

Answer 46

To proofread daughter strands as they are being produced

Question 47

What happens if DNA polymerase fails to catch when a wrong nucleotide is added?

Answer 47

Mutation

Question 48

Termination

Answer 48

Third and final stage in DNA replication DNA copies are finalized and safe guarded from degradation

Question 49

Termination sites

Answer 49

Found along parent strands Direct helicase and DNA polymerase to detach

Question 50

What do termination sites end in?

Answer 50

Replication fork

Question 51

What occurs before last nucleotide in DNA strand?

Answer 51

Termination sites

Question 52

What are the ends of chromosomes protected by?

Answer 52

Telomeres

Question 53

Telomeres

Answer 53

Long sequences of DNA that protect chromosome from damage

Question 54

What repeating sequence do human telomeres consist of?

Answer 54

TTAGGG

Question 55

When do telomeres add the repeating TTAGGG sequence?

Answer 55

After final replication fork

Question 56

What do telomeres lack?

Answer 56

The ability to code for proteins Don’t contain any hereditary information

Question 57

What happens when telomeres are used up due to excessive replications?

Answer 57

Genetic information is lost severely impacting organism health

Question 58

What happens when telomeres are lost?

Answer 58

Chromosomes can no longer replicate Can’t heal, grow or reproduce

Question 59

Hayflick limit

Answer 59

Number of times DNA can replicate before using up all its telomeres

Question 60

Senescence

Answer 60

Process of shortening your telomeres over time (cellular aging)