Molecular Basis of Inheritance Flashcards
1
Q
____ is the genetic material
A
DNA
2
Q
_____ work together in DNA replication and repair
A
many proteins
3
Q
what does a chromosome consist of
A
a DNA molecule packed together with proteins
4
Q
the molecule of inheritance
A
DNA
5
Q
what is the most celebrated molecule of our time
A
DNA
6
Q
what is hereditary information coded by
A
DNA
7
Q
hereditary information is reproduced in
A
all cells of the body
8
Q
what does the DNA program direct the development of
A
biochemical, anatomical physicological and behavioral trait s
9
Q
who introduced the double-helical model of DNA
A
James Watson and Francis Crick
10
Q
when is DNA copied
A
during DNA replication
11
Q
can cells repair their DNA
A
YES
12
Q
T H Morgan’s group showed that
A
genes are located on chromosomes
13
Q
what became candidates for genetic material
A
proteins and DNA
14
Q
a key factor for determining genetic material was
A
choosing appropriate experimental organisms
15
Q
how was the role of DNA in heredity first discovered
A
studying bacteria and viruses
16
Q
can a genetic trait be transferred between different bacterial strains
A
YES
17
Q
transformation
A
change in genotype and phenotype due to assimilation of foreign DNA
18
Q
only____ worked in transforming harmless bacteria into pathogenic bacteria
A
DNA
19
Q
bacteriophages
A
viruses that target bacteria
20
Q
what is a virus
A
DNA that is enclosed by a protective coat
21
Q
what is the protective coat of a virus mostly made from
A
proteins
22
Q
can viruses be RNA
A
YES
23
Q
does a protein enter a phage
A
NO
24
Q
does DNA enter a phage
A
YES
25
is Protein or DNA the genetic material of phage T2?
DNA
26
DNA is a polymer of
nucelotides
27
each nucleotide consists of
1. nitrogenous base
2. sugar
3. phosphate group
28
DNA composition _____ from one species to the next
varies
29
what made DNA a more credible candidate for genetic material
the evidence of diversity
30
Chargaff's rule
1. base composition of DNA varies between species
2. the number of A and T bases are equal
3. the number of G and C bases are equal
31
what led to the understanding of base pairing rules
discovery of double helix
32
what end do you add nucleotides to
3' end
33
what is located at the 3' end that allows binding of nucleotides
OH
34
what end contains a phosphate
5' end
35
what makes up the backbone
sugar and phosphate group
36
what makes up the branches in DNA
nitrogenous bases
37
what was the challenge of the DNA structure
how it accounts for role in heredity
38
what was used to study the molecular structure of DNA
Z-ray crystallography
39
who produced a picture of the DNA molecule
Rosalind Franklin
40
what allowed Watson to deduce the DNA helical structure
Franklin's X-ray crystallographic image
41
DNA double helix was suggested based on
DNA molecule made up of two strands
42
one full turn of DNA is in
10 base pairs
43
1 nucleotide causes the DNA to turn
36 degrees
44
diameter of double helix
2 nm
45
bases are _____ apart
0.34 nm
46
covalent _________ bonds link
sugar-phosphate AND the nucleotides of each strand
47
hydrogen bonds are between
nitrogenous bases
48
what kind of bond holds the stands together
hydrogen bonds
49
Van de Waals interactions are between
stacked bases pairs
50
Van der Waals interactions help
hold the molecule together
51
where are base pairs located in DNA
interior of the molecule
52
what makes the outer structure of DNA
two outer sugar-phosphate backbones
53
antiparallel
subunits run in opposite directions
54
what did Watson and Crick first think about base pair linkage
they would link like to like (A with A)
55
what happened when base pairs are linked in the like-to-like way
did not have a uniform width
56
how must base pairs link
purine with a pyrimidine
57
why must a purine pair with a pyrimidine
makes a uniform width
58
what happens when two PURINES link
width is too large
59
what happens when two PYRIMIDINES link
too narrow
60
what nucleotides are purines
A and G
61
what nucleotides are pyrimidines
T and C
62
what is smaller, pyrimidines or purines
pyrimidines
63
what is larger, pyrimidines or purines
purines
64
Adenine must pair with
thymine
65
guanine must pair with
cytosine
66
the amount of A equals
amount of T
67
the amount of G equals
amount of C
68
Adenine and thymine pair with a
doube bond
69
Guanine and Cytosine pair with a
triple bond
70
what base pair linkage will have a stronger link
guanine and cytosine
71
where is structure and function of DNA manifested
double helix
72
DNA strands are
complementary
73
with DNA strands being complementary, each acts as a
template for building a new strand
74
DNA replication has the ______ unwinding
parent molecule
75
two daughter strands are built based on
base-pairing rules
76
semiconservative model of replication predicts
when a double helix replicates, each daughter molecule will have ONE parental strand and ONE newly made strand
77
three alternative models of DNA replication
1. conservation model
2. semiconservative model
3. dispersive model
78
conservative model
the two parent strand rejoin
79
dispersive model
each strand is a mix of old and new strands
80
What model of DNA replication is this?
Dispersive
81
What model of DNA replication is this?
Conservative
82
What model of DNA replication is this?
Semiconservative
83
Does DNA replication follow conservative, semiconservative or dispersive model
semiconservative
84
first replication in the experiment produced a bond of hybrid DNA which eliminates
conservative model
85
second replication in the experiment produced both a light and hybrid DNA which eliminates
dispersive model
86
where does replication begin
origins of replication
87
origin of replication is the place where
two strands of DNA are separated and open up with a replication bubble
88
at the origin of replication, replication happens
in BOTH directions
89
where do the two new daughter strands START to form
origins of replication
90
a eukaryotic chromosome has
multiple origins of replication
91
what shape of the replication fork
Y shaped region
92
where do the new DNA strands elongate
replication fork
93
what is at the end of each replication bubble
replication fork
94
helicases
enzymes that untwist the double helix at replication forks
95
single-strand binding proteins
bind to and stabalize single-stranded DNA
96
single-strand binding proteins
bind to and stabilize single-stranded DNA
97
Topoisomerase
corrects "overwinding" (stress) ahead of replication forks
98
how does topoisomerase correct overwinding
by breaking, swivelling and rejoining DNA strands
99
what enzyme can we not replicate DNA without
topoisomerase
100
a double-stranded DNA has better
protection compared to single-stranded
101
primase is needed in _____ but NOT _____
DNA and RNA
102
primase allows
polymerase to start adding nucelotides
103
can DNA polymerase initiate synthesis of a polynucleotide
NO
104
DNA polymerase can only
add nucleotides to an existing 3' end
105
initial nucleotide strand is
short RNA primer
106
______ can start an RNA chain and add RNA nucleotides one at a time
primase
107
how can primase add RNA nucleotides one at a time
using parental DNA as a template
108
what serves as the starting point for the new DNA strand
3' end of short primer
109
DNA polymerase
catalyze elongation of new DNA at the replication fork
110
Is RNA polymerase involved in DNA synthesis
nO
111
what polymerase catalyzes the elongation of new DNA at replication fork
DNA
112
what do most DNA polymerases require
primer and DNA template strand
113
elongation is faster in
bacteria than human cells
114
what is each nucleotide added to a growing DNA strand
nucleoside triphosphate
115
nucleosides are missing the
phosphate group
116
dATP differs from ATP by the
sugar
117
dATP has a
deoxyribose
118
ATP has a
ribose sugar
119
dATP
supplies adenine to DNA
120
what happens every time a new nucleotide is added to the growing DNA strand
loses two phosphate groups
121
what is the molecule known as when a nucleotide loses two phosphate groups
pyrophosphate
122
the antiparallel structure of the double helix affects
replication
123
DNA polymerase adds nucleotides to the
3' end
124
a new DNA strand can ONLY elongate in the
5' to 3' direction
125
Leading strand
continuously moving toward the replication fork
126
the leading strand is elongated in the ____ direction
5' to 3'
127
Is C the leading or lagging strand
lagging strand
128
Is B a leading or lagging strand
Leading strand
129
how must ____ work to elongate lagging strands
DNA polymerase AND away from replication fork
130
the ____ strand is made up of Okazaki Fragments
lagging
131
the lagging strand is made up of
Okazaki Strand
132
how are Okazaki fragments joined
DNA ligase
133
what unwinds the parental double helix
helicase
134
what strand is synthesised continuously
leading strand
135
what do the proteins in DNA replication forming
DNA replication machine
136
the DNA replication machine may be ))))) during replication
stationary
137
DNA ligase
joins Okazaki fragments of lagging strand
138
what does DNA ligase do on the leading strand
joins 3' end of DNA that replaces primer to rest of leading strand DNA
139
DNA Pol I
removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides
140
DNA pol III
using parental DNA as a template, synthesizes new DNA strand by adding nucleotides to an RNA primer or preexisting DNA strand
141
what proofreads newly made DNA and replaces any incorrect nucelotides
DNA polymerase
142
mismatch repair
repair enzymes correct errors in base pairing
143
nucleotide excision repair
a nuclease cuts out and replaces damaged stretches of DNA
144
is error rate after proofreading zero
NO
145
what happens to sequence changes that are permanent
passed to next generation
146
what are source of genetic variation
mutations
147
natural selection operates upon
mutations
148
what creates problems for linear DNA of eukaryotic chromosomes
limitations of DNA polymerase
149
does the usual replication machinery provide a way to complete the 5' end
NO
150
what happens with repeated rounds of replication
shortening of DNA molecules at the ends
151
is shortening of DNA molecules at the ends a problem for prokaryotes
NO, they have round chromosomes
152
the ends of DNA molecules after repeated rounds of replication are
uneven
153
what do eukaryotic chromosomal DNA molecules have at their ends
telomeres
154
telomeres do what
postpone erosion of genes near the ends of chormosomes
155
do telomeres prevent shortening of DNA molecules
NO
156
what is connected to aging
shortening of telomeres
157
what would happen if germ cells became shorter in every cell cycle
genes would be missing from gametes produced
158
what catalyzes the lengthening of telomeres in germ cells
telomerase
159
what can protect cells from cancerous growth
telomeres
160
how can telomeres protect cells from cancerous growth
limits the number of cell divisions
161
what happens as telomeres shorten
there is a loss of cell viability
162
bacterial chromosomes are
double-stranded, circular DNA molecules
163
eukaryotic chromosomes are
linear DNA molecules
164
do eukaryotic or bacterial chromosomes have LOTS of proteins
eukaryotic
165
do eukaryotic or bacterial chromosomes have LITTLE of proteins
bacterial
166
where is DNA found in bacterium
nuceloid
167
chromatin
complex of DNA and protein
168
where is chromatin found
nucleus of eukaryotic cells
169
what undergoes a change in packing during the cell cycle
chromatin
170
what is chromatin like in interphase
organized into a 10 nm fibre or most is compacted into a 30 nm fibre
171
do interphase chromosomes become entangled
NO
172
what is chromatin like in interphase
loosely packed
173
what does chromatin do prior to mitosis
condenses
174
euchromatin
loosely packed chromatin
175
heterochromatin
centromeres and telomeres become highly condensed during interphase
176
what does dense packing make difficult
to express genetic information coded in these regions
177
what undergo chemical modifications that result in changes in chromatin organization
histones
178
histones
responsible for the first level of DNA packing in chromatin
