CH1 | Introduction to Molecular Biology Flashcards
1
Q
Molecular biology studies…
A
cellular biochemical and molecular processes.
2
Q
Nucleic acids are macromolecules made of…
A
nucleotides.
3
Q
Nucleic acids function to…
A
store and transmit genetic information and regulate protein synthesis.
4
Q
The two classes of nucleic acids are…
A
DNA and RNA.
5
Q
DNA stands for…
A
deoxyribonucleic acid.
6
Q
RNA stands for…
A
ribonucleic acid.
7
Q
The three components of a nucleotide are…
A
phosphate group, pentose sugar, nitrogenous base.
8
Q
The phosphate group in nucleotides is…
A
the same in both DNA and RNA.
9
Q
The pentose sugar in DNA is…
A
deoxyribose.
10
Q
The pentose sugar in RNA is…
A
ribose.
11
Q
Difference between ribose and deoxyribose is…
A
2’ carbon in ribose is -OH, 2’ carbon in deoxyribose is -H
12
Q
The nitrogenous bases in DNA are…
A
adenine, guanine, cytosine, thymine.
13
Q
The nitrogenous bases in RNA are…
A
adenine, guanine, cytosine, uracil.
14
Q
Adenine and guanine are classified as…
A
purines.
15
Q
Cytosine, thymine, and uracil are classified as…
A
pyrimidines.
16
Q
In RNA, the base that replaces thymine is…
A
uracil.
17
Q
Purines are characterized by…
A
a double-ring structure.
18
Q
Pyrimidines are characterized by…
A
a single-ring structure.
19
Q
Nucleobase is also known as…
A
a nitrogenous base.
20
Q
A nucleoside is made of…
A
nucleobase + sugar.
21
Q
A nucleotide is made of…
A
nucleoside + phosphate.
22
Q
DNA is described as being…
A
double-stranded, complementary, and antiparallel.
23
Q
Double-stranded means…
A
two strands of nucleotides.
24
Q
Complementary means…
A
bases pair up according to specific rules (A-T, C-G).
25
Antiparallel means...
the two strands run in opposite directions (5' to 3' and 3' to 5').
26
DNA has directionality, which is...
5' to 3'.
27
In DNA, A bonds with...
T (via 2 hydrogen bonds).
28
In DNA, C bonds with...
G (via 3 hydrogen bonds).
29
DNA forms a double helix because...
the nucleotides of the two strands wrap around each other.
30
RNA is typically...
single-stranded.
31
RNA carries genetic information from...
DNA in the nucleus to the cytoplasm.
32
RNA's primary function is to...
build proteins.
33
The two main categories of RNA are...
coding and non-coding RNA.
34
mRNA is a type of...
coding RNA.
35
tRNA, rRNA, lncRNA are types of...
non-coding RNA (ncRNA).
36
miRNA, snoRNA, siRNA, snRNA are types of...
small ncRNA.
37
The four nucleobases of RNA are...
Uracil, Cytosine, Adenine, Guanine.
38
A gene is a section of...
DNA.
39
Genes contain instructions for...
building proteins.
40
Genes store information that is...
passed down through generations.
41
Gene size varies from...
a few hundred bp to over 2 million bp.
42
"bp" in the context of genes stands for...
base pairs.
43
The Human Genome Project estimated that humans have about...
20,687 protein-coding genes.
44
Genes are located in the...
cell nucleus.
45
Gene is part of a structure called...
chromosome.
46
Eukaryotic genes' structure consists of...
an upstream regulatory sequence, an open reading frame and a downstream regulatory sequence.
47
The open reading frame (ORF) contains...
exons and introns.
48
Exons are...
protein-encoding DNA sequences (1.5%).
49
Introns are...
non-coding segments removed by splicing (>98%).
50
The 5' upstream regulatory sequence contains the...
promoter region.
51
The promoter region controls...
gene expression.
52
The 3' downstream regulatory sequence regulates...
termination of gene expression.
53
Enhancer/Silencer regions are located in...
distal control elements (upstream or downstream)
54
Terminator sequence are located in...
downstream regulatory sequence.
55
TATA box is located in...
promoter region.
56
Poly-A tail is located in...
downstream regulatory sequence (after the last exon).
57
An organism's full set of genes is called the...
genome.
58
Humans have approximately ... base pairs.
3 billion
59
Humans have a total of ... chromosomes, ... from each parent.
46, 23
60
Humans have approximately ... base pairs.
3 billion
61
Different forms of genes are called...
alleles.
62
Alleles are...
Different forms of the same gene.
63
A fixed position on a chromosome where a gene is located is called a...
locus (loci).
64
Locus is...
the specific location of a gene on a chromosome.
65
Homologous chromosomes are...
chromosome pairs, one from each parent.
66
Homozygous means...
having two identical alleles for a gene.
67
Heterozygous means...
having two different alleles for a gene.
68
Humans have ... chromosomes in every cell.
46
69
Autosomes (1-22) are...
diploid.
70
Diploid means...
having two sets of homologous chromosomes.
71
Haploid means...
having a single set of unpaired chromosomes.
72
The number and visual appearance of the chromosomes in the cell nuclei of an organism or species is called...
a karyotype.
73
When not being replicated or transcribed, DNA is stored in...
thread-like structures inside the nucleus.
74
DNA is packaged to...
protect it and aid in DNA replication.
75
Chromosomes have a constricted region called the...
centromere.
76
The ends of chromosomes are called...
telomeres.
77
Chromosomes have a short arm called the...
p arm.
78
Chromosomes have a long arm called the...
q arm.
79
Based on centromere position, the 4 types of chromosomes are...
metacentric, submetacentric, acrocentric, telocentric.
80
Telomeres are located at...
the ends of chromosomes.
81
Telomeres are made of...
non-coding repetitive DNA sequences.
82
The specific DNA sequence of telomeres is...
5'-TTAGGG-3'.
83
Telomeres function to...
maintain chromosome structural integrity.
84
Telomeres prevent attack by...
enzymes.
85
As cells divide, telomeres...
shorten.
86
Telomere shortening eventually leads to...
cell senescence (cell stops dividing).
87
DNA replication is the process by which a cell...
makes an identical copy of its DNA.
88
DNA replication is essential for...
the transmission of genetic information to the next generation.
89
In eukaryotic cells, DNA replication occurs in the...
nucleus.
90
In prokaryotic cells, DNA replication occurs in the...
cytoplasm.
91
DNA replication occurs during the...
S phase of interphase.
92
During the cell cycle, DNA Synthesis happens in the...
S phase.
93
Interphase consists of...
G1, S, and G2 phases.
94
DNA replication is described as...
semi-conservative.
95
Semi-conservative replication means...
each new DNA molecule has one old strand and one new strand.
96
Each strand in a DNA molecule serves as a...
template for synthesis of a new, complementary strand.
97
Template strand is...
the original DNA strand used to synthesize a new strand.
98
Complementary strand is...
the new DNA strand synthesized using the template strand.
99
Semi-conservative replication ensures that...
genetic information is accurately transmitted to the next generation.
100
Semi-conservative replication allows for genetic variation through...
mutations during DNA replication.
101
The three stages of DNA replication are...
initiation, elongation, and termination.
102
DNA replication begins at specific locations called...
origins of replication.
103
The origin of replication is located by...
pre-replication protein complexes.
104
The enzyme that temporarily breaks the DNA backbone to unwind it is...
topoisomerase.
105
The enzyme that unwinds DNA by breaking hydrogen bonds is...
helicase.
106
The enzyme that "unzips" the DNA is...
helicase.
107
Proteins that stabilize the unwound DNA are...
single-stranded binding proteins (SSBs).
108
The Y-shaped structure formed during initiation is called the...
replication fork.
109
During replication, each DNA strand acts as a...
template that is replicated differently.
110
In DNA replication, new nucleotides are added in the ... direction.
5' to 3'
111
The enzyme that adds a short RNA primer to start replication in the leading strand is...
primase.
112
The leading strand is synthesized...
continuously, towards the replication fork.
113
The enzyme that adds new nucleotides to the leading strand is...
DNA polymerase (δ and ε).
114
The lagging strand is synthesized...
discontinuously, away from the replication fork.
115
The short DNA fragments synthesized on the lagging strand are...
Okazaki fragments.
116
On the lagging strand, numerous ... are needed.
RNA primers.
117
Okazaki fragments are approximately ... base pairs long.
100-200
118
The enzyme that removes RNA primers is...
RNase H.
119
After RNA primer removal, the gap is filled by...
DNA polymerase.
120
The enzyme that joins Okazaki fragments is...
DNA ligase.
121
DNA ligase joins Okazaki fragments by forming...
phosphodiester bonds.
122
The role of DNA ligase is to...
connect DNA fragments by forming phosphodiester bonds between them.
123
Exonuclease is...
an enzyme that removes RNA primers (e.g. RNase H).
124
At the end of replication, the lagging strand is...
shorter than the leading strand.
125
The RNA primer at the end of the lagging strand cannot be replaced with DNA because...
there is no free 3' OH group for DNA polymerase to add to.
126
The end replication problem leads to a gap in the...
newly synthesized DNA strand at the end of the chromosome.
127
The extreme 5' end of the lagging strand...
is not replicated.
128
The enzyme that extends telomeres is...
telomerase.
129
Telomerase binds to the...
3' overhang of the telomere.
130
Telomerase uses ... as a template
internal telomerase RNA
131
Telomerase extends the telomere by adding...
DNA nucleotides complementary to its internal RNA template.
132
After telomerase extends the 3' overhang, ... can bind, which extends...
DNA Polymerase α, an RNA primer to synthesize a complementary strand.
133
Approximately, ... nucleotides need to be correctly inserted during DNA replication in a human diploid cell.
6 billion
134
DNA polymerases can make mistakes, leading to...
base mismatches.
135
Most replication errors are corrected by...
DNA polymerase itself.
136
The specific type of DNA polymerase that proofreads is...
DNA polymerase β.
137
DNA polymerase β has what type of activity for proofreading?
3' to 5' exonuclease activity.
138
After the mispaired nucleotide is removed, DNA polymerase...
fills the gap with the correct nucleotides.
139
The enzyme that seals the gap after error correction is...
DNA ligase.
140
The enzyme that relieves torsional strain ahead of the replication fork is...
topoisomerase.
141
Topoisomerase relieves torsional strain by...
breaking and rejoining DNA strands.
142
The enzyme that unwinds the DNA double helix at the replication fork is...
helicase.
143
Helicase unwinds DNA by...
breaking hydrogen bonds between the two strands.
144
The proteins that bind to single-stranded DNA and prevent it from reannealing are...
single-stranded binding proteins (SSBs).
145
The enzyme that synthesizes short RNA primers is...
primase.
146
Primase provides a starting point for...
DNA polymerase.
147
The main enzyme that adds nucleotides to the new DNA strand is...
DNA polymerase (δ and ε).
148
DNA polymerase (δ and ε) adds nucleotides in the ... direction
5' to 3'
149
The enzyme that extends the complementary strand from an RNA primer is...
DNA polymerase α.
150
DNA polymerase α helps solve...
the end of replication problem.
151
The enzyme that has a proofreading function is...
DNA polymerase β.
152
The enzyme that cleaves the RNA primer is...
exonuclease.
153
The enzyme that joins Okazaki fragments on the lagging strand is...
DNA ligase.
