DNA

Question 1

Helicase

Answer 1

enzyme that unwinds/unzips double-stranded DNA

Question 2

Ligase

Answer 2

enzyme that acts like a glue, which can bind different pieces of DNA together

Question 3

DNA Polymerase

Answer 3

enzyme that creates DNA molecules by assembling nucleotides in the 5’ to 3’ direction and spell checks for errors

Question 4

Primase

Answer 4

enzyme that synthesizes RNA primers, which are short, single-stranded nucleic acid sequences that initiate DNA replication

Question 5

A

Answer 5

Adenine
-attracted to thymine

Question 6

T

Answer 6

Thymine
-attracted to adenine

Question 7

C

Answer 7

Cytosine
-attracted to guanine

Question 8

G

Answer 8

Guanine
-attracted to cytosine

Question 9

DNA Structure

Answer 9

double helix (also double stranded)

Question 10

Rosalind Franklin

Answer 10

discovered the structure of DNA (double helix - Photo 51)

Question 11

James Watson and Francis Crick

Answer 11

x-ray experiments by Rosalind Franklin led to James Watson and Francis Crick’s discovery of the structure of DNA in 1953

Question 12

Nucleotide

Answer 12

-a molecule that contains a sugar, a phosphate group, and a nitrogenous base
-nucleotides are the building blocks of DNA
-subunit of nucleic acid (smaller)

Question 13

DNA Backbone

Answer 13

a sugar-phosphate chain (sides of ladder)

Question 14

Sugar in DNA

Answer 14

deoxyribose

Question 15

Nitrogen Bases

Answer 15

steps of ladder, bonded together by hydrogen bonds

Question 16

Purines

Answer 16

2 rings (A and G)

Question 17

Pyrimidines

Answer 17

1 ring (C and T)

Question 18

Erwin Chargaff’s Rules

Answer 18

A=T
G=C
e.g. 20% A=T 20%

Question 19

Hydrogen Bonds

Answer 19

bonds between nitrogen bases that hold the two strands together

Question 20

Carbon 1’-5’

Answer 20

-the nitrogenous base is attached to the 1’ carbon
-the phosphate group is attached to the 5’ carbon
-each strand has a 5’ and 3’ end

Question 21

Anti-Parallel

Answer 21

strands that run in opposite directions

Question 22

DNA Molecule in Bacteria/Prokaryote

Answer 22

-single
-circular
-found in cytoplasm (no nucleus)

Question 23

DNA in Eukaryotes

Answer 23

-in multiple chromosome bundles
-found in nucleus

Question 24

Histones

Answer 24

proteins that help make up eukaryotic chromosomes

Question 25

Nucleosome

Answer 25

a bead-like structure formed by DNA and histone proteins

Question 26

Chromatin

Answer 26

-nucleosomes pack together to form thick coiled fibers -when a cell is not diving, these fibers are spread out as chromatin

Question 27

Chromosomes

Answer 27

-when cell gets ready to divide, the fibers pack even more tightly to form chromosomes -easier to move DNA during mitosis

Question 28

DNA Replication

Answer 28

-each strand has all the info needed to construct the matching other half -if strands are separated, base-pairing rules allow you to fill in the complementary bases

Question 29

Complementary Base

Answer 29

the precise matching of specific nitrogenous bases in DNA

Question 30

Okazaki Fragment

Answer 30

short, newly made DNA segments formed on the lagging strand during DNA replication

Question 31

Replication Forks

Answer 31

sites where strand separation and replication occur

Question 32

DNA Replication Steps

Answer 32

1. helicase unzips molecule by breaking hydrogen bonds that hold the strands together and unwinds it 2. primase synthesizes RNA primers that initiate DNA replication 3. DNA polymerase joins nucleotides using the original strand as a template and spell checks for errors 4. p53 checks for errors 5. ligase glues the strands together

Question 33

Semi-Conservative Replication

Answer 33

each newly formed DNA molecule consists of one original (parental) strand and one newly synthesized strand

Question 34

p53

Answer 34

a protein used to check DNA again for errors

Question 35

Mutation

Answer 35

a change in DNA sequence not fixed by DNA polymerase or p53

Question 36

RNA

Answer 36

-made of nucleotides -sugar is ribose -single stranded -contains uracil instead of thymine