6 Flashcards
(180 cards)
1
Q
Central Dogma of Biology
A
DNA → RNA → Protein.
2
Q
Transcription
A
The process of making RNA from a DNA template.
3
Q
Translation
A
The process of synthesizing a protein from an mRNA template.
4
Q
RNA polymerase
A
The enzyme that carries out transcription.
5
Q
RNA synthesis direction
A
5’ to 3’ direction.
6
Q
Types of RNA
A
mRNA, tRNA, rRNA.
7
Q
mRNA
A
Carries the genetic message from DNA to ribosomes.
8
Q
tRNA
A
Transfers specific amino acids to the ribosome during translation.
9
Q
rRNA
A
Forms part of the ribosome structure.
10
Q
Codon
A
A sequence of three RNA nucleotides that codes for an amino acid.
11
Q
Start codon
A
AUG, codes for Methionine.
12
Q
Stop codons
A
UAA, UAG, UGA.
13
Q
Initiation of transcription
A
RNA polymerase binds to the promoter region of DNA.
14
Q
Elongation in transcription
A
RNA polymerase adds RNA nucleotides to the growing strand.
15
Q
Termination in transcription
A
RNA polymerase reaches a stop signal and releases RNA.
16
Q
Transcription in eukaryotes
A
Occurs in the nucleus.
17
Q
Promoter
A
A DNA sequence where RNA polymerase attaches to start transcription.
18
Q
RNA processing
A
Involves 5’ capping, poly-A tail addition, and splicing.
19
Q
5’ cap
A
Added to the 5’ end of mRNA.
20
Q
Poly-A tail
A
Added to the 3’ end of mRNA.
21
Q
Splicing
A
Removal of introns and joining of exons in RNA.
22
Q
Introns
A
Non-coding sequences removed from pre-mRNA.
23
Q
Exons
A
Coding sequences that remain in mRNA.
24
Q
Spliceosome
A
The complex that performs splicing.
25
Alternative splicing
Different ways of joining exons to produce different proteins from one gene.
26
Mutation
A change in the DNA sequence.
27
Point mutation
A change in a single nucleotide base.
28
Silent mutation
A mutation that does not change the amino acid sequence.
29
Missense mutation
A mutation that changes one amino acid to another.
30
Nonsense mutation
A mutation that changes a codon to a stop codon.
31
Frameshift mutation
Insertion or deletion of a nucleotide that shifts the reading frame.
32
Somatic mutation
A mutation occurring in body cells.
33
Germline mutation
A mutation occurring in reproductive cells, passed to offspring.
34
Mutagen
A physical or chemical agent that causes mutations.
35
Chromosomal mutations
Large-scale changes affecting parts of chromosomes.
36
Types of chromosomal mutations
Deletion, Duplication, Inversion, Translocation.
37
Deletion mutation
Loss of a chromosome segment.
38
Duplication mutation
Repetition of a chromosome segment.
39
Inversion mutation
A chromosome segment is reversed end to end.
40
Translocation mutation
A segment of one chromosome breaks off and attaches to another chromosome.
41
snRNA
Participates in RNA splicing.
42
miRNA
Regulates gene expression by degrading mRNA or inhibiting translation.
43
siRNA
Silences gene expression by targeting mRNA for degradation.
44
Ribosome role in translation
Facilitates the linking of amino acids into a polypeptide chain.
45
Ribosome sites
A-site, P-site, E-site.
46
A-site function
tRNA carrying an amino acid enters.
47
P-site function
tRNA holds the growing polypeptide chain.
48
E-site function
Empty tRNA exits the ribosome.
49
Polysomes
Clusters of ribosomes translating the same mRNA.
50
polysomes
Multiple ribosomes translating one mRNA simultaneously.
51
proteolysis
Cutting of polypeptide chains.
52
glycosylation
Addition of sugars to proteins.
53
phosphorylation
Addition of phosphate groups to proteins.
54
transcription in prokaryotes vs eukaryotes
In prokaryotes, transcription and translation occur simultaneously; in eukaryotes, transcription occurs in the nucleus.
55
RNA polymerase II
Synthesizing mRNA.
56
anticodon
A three-nucleotide sequence on tRNA complementary to a codon on mRNA.
57
reading frame
The way nucleotides are grouped into codons for translation.
58
frameshift mutations
They alter the entire downstream amino acid sequence.
59
redundancy in the genetic code
Multiple codons can code for the same amino acid.
60
promoter sequence in prokaryotes
The -10 and -35 sequences.
61
TATA box
A promoter sequence found in eukaryotes.
62
transcription factors
Proteins that help RNA polymerase bind to DNA.
63
RNA polymerase during elongation
Adds complementary RNA nucleotides to the growing strand.
64
termination of transcription in prokaryotes
A terminator sequence.
65
termination of transcription in eukaryotes
By a polyadenylation signal followed by RNA cleavage.
66
5' cap on mRNA
Protects mRNA from degradation and helps ribosome binding.
67
poly-A tail
Stabilizes mRNA and facilitates nuclear export.
68
polypeptide
A chain of amino acids linked by peptide bonds.
69
first amino acid during translation
Methionine.
70
universal genetic code
Almost all organisms use the same codons for the same amino acids.
71
initiation of translation
The ribosome assembles around the start codon on mRNA.
72
role of GTP during translation
Provides energy for ribosome assembly and movement.
73
molecules involved in translation
mRNA, tRNA, rRNA, ribosomal proteins.
74
wobble hypothesis
Flexibility in base pairing between the 3rd base of a codon and anticodon.
75
enzyme that charges tRNA
Aminoacyl-tRNA synthetase.
76
translation elongation
Amino acids are added one by one to the growing polypeptide.
77
end of translation
A stop codon on the mRNA.
78
release factor
A protein that binds to the stop codon and releases the polypeptide.
79
linking amino acids
By a peptide bond.
80
mRNA after translation
It can be degraded or reused for further translation.
81
gene
A sequence of DNA that codes for a specific protein or RNA.
82
gene vs allele
A gene is a DNA sequence; an allele is a variation of that gene.
83
gene expression
The process of converting genetic information into a functional product.
84
regulatory sequence
DNA sequence that controls gene expression.
85
operon
A group of genes under control of one promoter in prokaryotes.
86
lac operon
A set of genes involved in lactose metabolism in bacteria.
87
regulation of lac operon
By the presence or absence of lactose.
88
enhancer
A DNA sequence that increases transcription when bound by proteins.
89
repressor
A protein that binds DNA and inhibits transcription.
90
mutation in promoter region
Transcription may be reduced or stopped.
91
frameshift mutation
It dramatically alters the entire downstream amino acid sequence.
92
nonsense mutations
They produce incomplete, nonfunctional proteins.
93
telomeres
Protect the ends of eukaryotic chromosomes.
94
telomerase
Enzyme that extends telomeres.
95
telomerase activity
Active in stem cells, germ cells, and cancer cells.
96
ubiquitin
Marks a protein for degradation.
97
proteasome
Where tagged proteins are degraded.
98
chaperone proteins
They help proteins fold correctly.
99
transcriptional regulation
Controlling when and how much RNA is made from DNA.
100
post-transcriptional regulation
Controlling RNA splicing, export, stability, and translation.
101
post-translational regulation
Modifying proteins after they are made.
102
mRNA degradation
The mRNA is broken down, stopping protein production.
103
shorter poly-A tails
Cause RNA to degrade faster.
104
oncogenes
Mutated genes that cause cancer by promoting cell division.
105
proto-oncogenes
Normal genes that can become oncogenes if mutated.
106
tumor suppressor genes
Genes that normally prevent cancer by inhibiting cell division.
107
p53 gene
An example of a tumor suppressor gene.
108
p53 protein
Triggers apoptosis or cell cycle arrest if DNA is damaged.
109
loss-of-function mutation in p53
Associated with increased cancer risk.
110
DNA repair enzymes
Fix mutations before they become permanent.
111
spontaneous mutations
Caused by errors in DNA replication or natural chemical changes.
112
induced mutations
Caused by mutagens like UV radiation, chemicals, or X-rays.
113
UV radiation
Causes mutations by creating thymine dimers that distort DNA structure.
114
X-rays
Cause mutations by breaking DNA strands.
115
hotspot mutation
A location in the genome with a higher mutation frequency.
116
redundant codons
Some mutations are silent because of redundancy.
117
mRNA length compared to DNA
mRNA is shorter than the DNA it's transcribed from because introns are removed during RNA processing.
118
accuracy during DNA replication
Ensured by proofreading by DNA polymerase.
119
accuracy during transcription
Ensured by specific binding of RNA polymerase to promoters.
120
accuracy during translation
Ensured by correct matching of codons and anticodons by tRNA.
121
5' untranslated region (5' UTR)
Regulates translation initiation without being translated into protein.
122
3' untranslated region (3' UTR)
Influences stability and localization of the mRNA.
123
gene promoter
Made of specific DNA sequences like the TATA box recognized by transcription factors.
124
negatively controlled operon
An operon controlled by a repressor.
125
positively controlled operon
An operon activated by an activator.
126
inducible operon
Turned on by a substrate.
127
repressible operon
Turned off by a product.
128
lac operon
An example of an inducible operon.
129
trp operon
An example of a repressible operon.
130
lactose and the lac operon
It binds to the repressor, causing it to detach from the operator.
131
enhancer region
Binds to activator proteins.
132
polycistronic mRNA
An mRNA that carries information for multiple proteins.
133
housekeeping genes
Genes that are constantly expressed to maintain basic cellular functions.
134
Constitutive Genes
Genes that are constantly expressed because they are needed all the time.
135
Neutral Mutation
A mutation that does not affect an organism's fitness.
136
Harmful Mutation
A mutation that decreases an organism's survival or reproduction.
137
Beneficial Mutation
A mutation that improves an organism's survival or reproduction.
138
Operon's Promoter
The site where RNA polymerase binds to start transcription.
139
Operator in an Operon
A DNA sequence where repressor proteins bind.
140
Proteomics
The study of the entire set of proteins produced by a cell.
141
Transcriptomics
The study of all RNA transcripts in a cell.
142
Sickle Cell Anemia Cause
A missense mutation in the hemoglobin gene.
143
Gene Duplication Mutation
A section of DNA is copied multiple times.
144
Gain-of-Function Mutation
A mutation that increases or changes a protein's activity.
145
Loss-of-Function Mutation
A mutation that reduces or eliminates protein function.
146
Chromosomal Translocation
A piece of one chromosome attaches to another chromosome.
147
Fusion Gene
A hybrid gene formed by chromosomal translocation.
148
5' Cap
A modified guanine nucleotide.
149
Poly-A Tail
A string of adenine nucleotides.
150
First Step in RNA Processing
Addition of the 5' cap.
151
Second Step in RNA Processing
Addition of the poly-A tail.
152
Third Step in RNA Processing
Splicing to remove introns.
153
Polyribosome
Multiple ribosomes attached to a single mRNA.
154
Codon
Three nucleotides make one codon.
155
Gene Mutation
A permanent change in the DNA sequence of a gene.
156
DNA Damage vs Mutation
Damage can be repaired; mutations are permanent.
157
Role of Helicase
Unwinds the DNA double helix during replication.
158
Role of Primase
Adds an RNA primer to DNA during replication.
159
Role of DNA Polymerase III
Adds new DNA nucleotides to the growing strand.
160
Role of DNA Polymerase I
Replaces RNA primers with DNA.
161
Role of Ligase
Seals gaps between Okazaki fragments on the lagging strand.
162
Okazaki Fragments
Short segments of DNA on the lagging strand.
163
Stabilization of Unwound DNA
Single-stranded binding proteins (SSB proteins).
164
Sliding Clamp
A protein that holds DNA polymerase onto DNA.
165
Semi-Conservative Replication
Each new DNA molecule has one old and one new strand.
166
Meselson and Stahl
Who proved DNA replication is semi-conservative?
167
Heavy Isotope in Meselson-Stahl Experiment
Nitrogen-15 (¹⁵N).
168
Light Isotope in Meselson-Stahl Experiment
Nitrogen-14 (¹⁴N).
169
Leading Strand
DNA is synthesized continuously toward the replication fork.
170
Lagging Strand
DNA is synthesized discontinuously away from the replication fork.
171
Telomere
A protective DNA sequence at the end of chromosomes.
172
Telomere Shortening
What shortens during each round of DNA replication in somatic cells?
173
Transcription Bubble
The open region of DNA where RNA is being synthesized.
174
RNA-DNA Hybrid
What structure forms during transcription?
175
Function of Ribosome's Small Subunit
Binds to the mRNA.
176
Function of Ribosome's Large Subunit
Joins amino acids together into a polypeptide.
177
Exonuclease
An enzyme that removes nucleotides from the ends of DNA or RNA.
178
RNA Polymerase I
Synthesizing rRNA.
179
RNA Polymerase III
Synthesizing tRNA and some small RNAs.
180
Classification of Gene Mutations
What are gene mutations classified by? Type of change and its effect on the protein.
