Unit 5

Question 1

watson and crick

Answer 1

discovered the double helix and twisted ladder structure of DNA

Question 2

T.H. Morgan

Answer 2

discovered that genes are located on chromosomes and the two components of chromosomes, DNA and proteins,

Question 3

Griffith

Answer 3

discovered the transforming of principle. He worked with mice and found transforming principles

Question 4

Avery

Answer 4

purified DNA by expanding on Griffiths work (his experiments gave DNA more weight for being genetic material)

Question 5

Hershey and Chase

Answer 5

worked with viruses (Bacteriophages) and further supported DNA, was responsible for genetic material

Question 6

Chargaff

Answer 6

discovered base pairing rules
(A=T, C=G)

Question 7

Franklin and Wilkins

Answer 7

used x-ray images which suggested that the DNA was made up of two strands forming a double helix
these images were used by Watson and Crick to determine the overall structure of DNA

Question 8

double helix structure

Answer 8

structure of DNA
2 linked strands that go around each other to resemble a twisted ladder

Question 9

nucleotide

Answer 9

the monomer of DNA
made up of three components: phosphate, sugar, base
there molecules bonded together creates 1 nucleotide

Question 10

pyrimidines

Answer 10

bases have a single ring as their structure
bases include cytosine, thymine, and uracil

Question 11

purines

Answer 11

bases have two rings as their structure
bases include guanine and adenine

Question 12

antiparallel- 5’ and 3’

Answer 12

opposite orientations of the two strands of DNA- the 5’ end of one strand aligns with the 3’ end of the other strand
5’ end always has a phosphate
3’ end always has a sugar

Question 13

base pairing rules

Answer 13

A always pairs with T (vice versa)
C always pairs with G (vice versa)
be able to do math problems on this

Question 14

semiconservative model of DNA

Answer 14

each molecule of DNA consists of one old (original) strand of DNA and one new strand that was created during DNA replication

Question 15

DNA Replication diagram

Answer 15

know what is what on the diagram we made and the steps

Question 16

helicase

Answer 16

unzips DNA molecule to access Nitrogen bases
#1 on diagram

Question 17

Single-stranded binding proteins

Answer 17

binds to the single strands of DNA and stabilizes it
keeps DNA apart to allow replication to occur
#3 on diagram

Question 18

Topoisomerase

Answer 18

binds ahead of the helicase to relieve strain on whole DNA molecule (does this by breaking bonds in backbone of DNA)
#2 on diagram

Question 19

DNA polymerase 3

Answer 19

finds primers to begin adding nucleotides to the new strand (by adding dATP); builder
#5 on diagram

Question 20

DNA polymerase 1

Answer 20

finds primers and cuts the RNA primers off and replaces it with DNA bases
#8 on diagram

Question 21

primase

Answer 21

lays primer; acts like a flag to let DNA polymerase 3 know where to bind/build
#4 on diagram

Question 22

primers

Answer 22

5-10 inch long RNA fragments that lay down the foundation for DNA synthesis; it allows DNA polymerase 3 to bind to the DNA strand
Dark pink on diagram

Question 23

ligase

Answer 23

takes the Okazaki fragments, once primers have been removed and glues them together
#9 on diagram

Question 24

leading strand

Answer 24

5’ to 3’
is built continuously due to the fact DNA polymerase can only build on the 3’ end
starts with a phosphate
top strand on diagram at the bottom and is #1 on the diagram to the side

Question 25

lagging strand

Answer 25

3' to 5' is built in short fragments because DNA polymerase can only add to the 3' end. therefore it is working backwards starts with a sugar bottom strand on diagram at bottom and #2 on the diagram to the side

Question 26

Okazaki fragments

Answer 26

short fragments of DNA on the lagging strand that will be glued together

Question 27

proofreading

Answer 27

all of DNA polymerase proofreads; during DNA replication the DNA polymerase can "check their work" with each base that they add

Question 28

direction of new synthesis and why?

Answer 28

DNA is synthesized in the 5'-3' direction Due to the fact that nucleotides are added only to the 3' end of the growing strand... this is because DNA polymerase can ONLY work in the 5'-3' direction and can only add bases to 3' end

Question 29

origin of replication

Answer 29

where the two DNA strands are separated, opening up a replication "bubble"

Question 30

replication fork

Answer 30

a Y-shaped region where the parental strands of DNA are being unwound

Question 31

dATP

Answer 31

a molecule that is used to build the new strand of DNA, dATP has three phosphates, a ribose sugar and a nitrogen base. This molecule will break two phosphates off and use the energy that is released by the breaking of the bonds to bind the new nucleotide (phosphate, deoxyribose sugar, nitrogen base) to the new DNA strand

Question 32

nucleotide excision repair

Answer 32

more than 1 base pair needs to be fixed, a nuclease cuts out and replaces damaged stretches of DNA STEPS: nuclease cuts out damaged DNA, DNA polymerase rebuilds, ligase glues it down excision repair is a process that is only successful when all three steps are completed

Question 33

nuclease

Answer 33

cuts out and replaces damaged stretches of DNA

Question 34

nucleoid

Answer 34

contains genetic material of the prokaryotic cell

Question 35

telomeres

Answer 35

eukaryotic chromosomal DNA molecule have special nucleotide sequences at their ends called telomeres they are noncoding regions of the DNA on the end of chromosomes does not shot the shortening of DNA molecules but does post pone the loss of genetic information (everytime DNA is replicated it becomes shorter)

Question 36

telomerase

Answer 36

An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells not active in most human somatic cells; however, it does show inappropriate activity in some cancer cells and understudy as a target for cancer therapies

Question 37

chromatin

Answer 37

proteins (histones) plus DNA... it is the essence of a chromatid

Question 38

histones

Answer 38

proteins responsible for wrapping the DNA to form a chromatid

Question 39

what types of bonds are between bases

Answer 39

hydrogen bonds

Question 40

how many bonds between G and C

Answer 40

3 hydrogen bonds

Question 41

what types of bonds are in the backbone of DNA

Answer 41

covalent bonds

Question 42

what two molecules make up the backbone of DNA

Answer 42

alternates with sugar (deoxyribose) and phosphate

Question 43

how many bonds between A and T

Answer 43

2 hydrogen bonds