12-13 (1) DNA & Protein Synthesis; Regulation of Gene Expression & Mutations Flashcards
1
Q
Polypeptide or proteins are translated from mRNA by a translation machinery called
A
Ribosome
2
Q
Difference between 30s subunit and 50s subunit
A
30s fits mRNA. 50s has catalytic functions
3
Q
Diffrence betrween ribosomes and codons
A
Ribosomes translate the mRNA by reading nucleotides as codon while codons are a sequence of three nucleotidesin mRNA that corresponds to a specific amino acid making the polypeptide
4
Q
How do Quinolones treat bacterial infections
A
Quinolones bind to DNA gyrase inhibitng DNA replication necessary of cell division and bacteria eventually die off
5
Q
Expression of the genetic information is quantitatively increased by the presence of a specific regulatory element
A
Positive regulation
6
Q
Specific regulatory element whose presence quantitatively increases expression of genetic information
A
Activator/inducer
7
Q
Expression of the genetic information is diminished by specific regulatory elements
A
Negative regulation
8
Q
Specific regulatory element that diminishes expression of the genetic information
A
Repressor
9
Q
True or False: Regulation of gene expression occurs only at one step of gene expression
A
False. Regulation occurs at different steps
10
Q
Gene expression is controlled mainly at ____ level
A
Transcription
11
Q
Examples of RNA molecules needed for the formation of a polypeptide chain
A
mRNA, tRNA, rRNA
12
Q
Forms a structural protein or an enzyme
A
Polypeptide
13
Q
True or False: Some proteins may also be involved in the control of gene expression
A
TRUE
14
Q
Prokaryotic cells use ___ in regulating expression of genes
A
Operons
15
Q
Eukaryotic cells use a variety of mechanisms to decrease or increase the expression of a gene due to ____
A
Complexity
16
Q
Most common form of regulating gene expression
A
Changing the rate of transcription
17
Q
True or False: Transcription can only be upregulated
A
FALSE
18
Q
Gene that needs an inducer/activator
A
Inducible
19
Q
Housekeeping genes
A
Constitutive
20
Q
Genes that are expressed at a constant rate
A
Constitutive
21
Q
Five important components of a gene
A
Exons, introns, transcription start site, (core and upstream) promoter, enhancer
22
Q
Segments of the eukaryotic gene that code for a polypeptide
A
Exons
23
Q
Separated by intervening sequences known as introns
A
Exons
24
Q
Intervening sequences that separate exons
A
Introns
25
Do not code for useful polypeptides
Introns
26
Sections that are removed during RNA processing
Introns
27
During what part of RNA processing are introns removed?
RNA splicing
28
Removal of introns bring ___ together
Exons
29
Site where initiation of transcription takes place
Transcription start site
30
Site where RNA polymerase binds and begins the process of transcription
Transcription start site
31
Binds to the transcription start site to begin the process of transcription
RNA polymerase
32
Contains a consensus sequence
Core promoter
33
Sequence that will remain consistent or the same in all chains of a eukaryotic organism
Consensus sequence (in core promoter)
34
Can be observed in all cell types and in all tissue types
Core promoter
35
Has the consensus sequence TATA in all cell type
TATA box
36
Consensus sequence of TATA box
TATA
37
Binding site for all essential transcription factors and regulatory proteins
Core promoter
38
Complex formed at the core promoter that is essential for transcription to take place
Large transcription factor-protein complex
39
Function of the large transcription factor-protein complex on the TATA box
Recruit binding of other proteins
40
Contains the TATA binding protein that recognizes and binds to the TATA box
Transcription factor IID
41
Assists TATA binding protein to interact with RNA polymerase
Transcription factor IIB
42
Allows the binding of the other proteins that can either activate or inhibit transcription
Upstream promoter
43
True or False: The number, type, and sequence of the upstream promoter is the same in all organisms
FALSE
44
Examples of upstream promoters
CCAAT, GC-rich region that binds general transcription factors
45
The enhancer may be up to ___ bp away from the gene
1000
46
True or False: The enhancer can only be located upstream or downstream of a gene
False. The enhancer may also be located within an intron of a gene
47
Loops or bends around the DNA after binding to the enhancer
Special transcription factor
48
Specific sequences of nucleotides found in the gene that serve as a binding site for transcription factors and regulatory proteins
Silencers
49
Two types of regulatory proteins
Activator proteins, repressor proteins
50
Regulatory proteins that bind to the enhancers
Activator proteins
51
Regulatory proteins that bind to silencers
Repressor proteins
52
Two categories of regulators based on location
Cis-acting regulators, trans-acting regulators
53
DNA sequences to which transcriptions factors and activators bind
Cis-acting regulators
54
Regulators that exert only on nearby genes
Cis-acting regulators
55
Include all regulatory protein that bind to cis-acting regulators
Trans-acting regulators
56
Genes that produce general transcription factors are under what category of regulators?
Trans-acting regulators
57
Response element (binding site) of SP-1
GC-rich
58
Response element (binding site) of NF-1
CCAATT box
59
Response element (binding site) of steroid receptor
HRE
60
Response element (binding site) of cAMP response element (CREB) protein
CRE response element
61
A cluster of genes that are transcribed together under a single promoter
Operon
62
True or False: The lac operon is turned on by default
FALSE
63
The lac operon is inducible upon presence of ___
Lactose
64
Components of lac operon
Regulatory gene (lac i), promoter site (P), operator site (O), three structural genes (lacZ, lacY, lacA)
65
Produces the repressor protein in lac operon
Regulatory gene (lac i)
66
Where lac repressor binds to block RNA polymerase from binding to promoter site and thus prevent transcription
Operator site (O)
67
Three structural genes of lac operon
lacZ, lacY, lacA
68
Structural gene that hydrolyzes lactose into glucose and galactose
lacZ
69
Structural gene for transport of lactose across the cell membrane
lacY
70
Structural gene for β-galactosidase
lacZ
71
Structural gene for permease
lacY
72
Structural gene for thiogalactoside transacetylase
lacA
73
True or False: Bacteria usually depends on lactose as a primary energy source
FALSE
74
Lac operon uses ___ as energy source upon absence of glucose
Lactose
75
In the absence of lactose and presence of glucose, there is ___ by lac repressor
Negative regulation
76
The Lac repressor binds to the ___ to block RNA polymerase access of the structural genes
O site
77
True or False: In the absence of lactose and presence of glucose, there is active transcription and translation.
FALSE
78
Positive control by induction of expression happens in the ___ of lactose and ___ of glucose (absence/presence)
Presence, absence
79
Allows transport of lactose through the cell membrane
Permase
80
Cleaves lactose into glucose and galactose
β-galactosidase
81
Formed by combining glucose and galactose through α1-6 linkage
Allolactose
82
Linkage that combines glucose and galactose to form allolactose
α1-6 linkage
83
In positive control by induction of expression, allolactose serves as ___ and binds the repressor protein
Inducer
84
Positive control by catabolite repression happens in the ___ of lactose and ___ of glucose (absence/presence)
Presence, presence
85
Glucose inhibits the high rate of transcription by lowering the concentration of ____
cAMP
86
When glucose is exhausted, cAMP concentration ____
Increases
87
cAMP binds to ___, forming a complex that binds to the ___ in the promoter
CAP-binding protein, CAP-binding site
88
Genes for the enzymes of tryptophan biosynthetic pathway
Tryptophan operon
89
True or False: The tryptophan operon is turned off by the presence of a repressor (repressible gene)
TRUE
90
In the tryptophan operon, what is the inactive repressor produced by the regulatory gene?
Apo-repressor
91
Proteins necessary for tryptophan synthesis are produced by the ___ of the tryptophan operon
5 structural genes
92
True or False: The Tryptophan operon is turned off during the absence of Tryptophan
FALSE
93
True or False: When the tryptophan operon is on, the Apo-repressor cannot bind the operator site
TRUE
94
Transcription is ___ when there is an excess in tryptophan
Repressed
95
Tryptophan acts as a ___, activating the Apo-repressor (inactive repressor)
Co-repressor
96
Premature termination of transcription
Attenuation
97
Regulation by attenutation depends on ___ and ___
Coupled transcription, translation
98
True or False: Regulation by attenuation never occur in eukaryotes
TRUE
99
Contains genes for histidine synthesis and produces histidine enzymes for the biosynthetic pathway of histidine when histidine is not available in the medium
His operon
100
True or False: When histidine is available, the His operon is turned on.
FALSE
101
One way to control the His operon
Attenuation
102
Transcription is constitutively initiated at the ___ of mRNA
5' UTR
103
As soon as the ____ appears at the 5’ UTR of the mRNA, ribosome binds to translate the 5’ UTR (leader sequence) into a non-functional protein known as the ____.
Shine-Dalgarno, leader peptide
104
True or False: If histidine is abundant, the ribosome easily finds His tRNA and the leader peptide is formed
TRUE
105
Secondary structure formed in His operon
Hairpin loop
106
In the His operon, what stops transcription before it reaches the structural genes?
RNA polymerase
107
True or False: In the absence of histidine, the ribosome stalls at histidine codon because it cannot easily find His tRNA.
TRUE
108
What provides a barrier for the formation of the transcriptional apparatus?
Nucleosome Core
109
True or False: Chromosomes of eukaryotes require remodeling
TRUE
110
Chromatin or Nucleosome remodeling is important to activate the ___
Gene
111
True or False: Chromatin or Nucleosome requires the use of energy
TRUE
112
A type of histone modification that transfer the acetyl group from acetyl coA to lysine residues
Covalent Modification
113
What is the main enzyme responsible for covalent modification?
Histone acetyltransferases (HATs)
114
Covalent modification of histones reduces _____ interaction between histone and DNA
Electrostatic
115
Repressors and co-repressors can contain ______ which inactivates the gene
Histone deacetylases
116
True or False: Does chemical modification of DNA change the sequences of the base pairs?
FALSE
117
Methylation of cytosine in CG pairs result in?
Silencing of the Gene
118
A highly compacted region during interphase and found in regions near the centromere
Heterochromatin
119
Methylation on the CPG island of the FMR1 gene result in the condition called?
Fragile X syndrome
120
Cytosine is methylated to _____ which inactivates the gene
5-methylcytosine
121
True or False: DNA methylation usually occurs in CpG islands
TRUE
122
CpG islands can usually be found near
Promoters
123
Complete and partial deletion of genes is called?
Gene Loss
124
Gene loss results in
Non-production of a functional protein
125
Gene amplifcation is the process of?
Repeated cycles of replication of genetic material
126
True or False: Gene modification usually occurs in physiological conditions
FALSE
127
Newly synthesized DNA which is excised into unstable chromosome to form
Double Minutes
128
DNA sequences that control gene activity
Enhancers and Silcencers
129
True or False: Enhancers and Silencers are found near the promoter?
FALSE
130
Proteins which bind to enhancers and silencers?
Activators and Repressors
131
Activator proteins that bind to response elements
Transcription Factors
132
What are the 2 recognizable domains of Transcription Factors?
DNA-bindign Domain and Activation Domain
133
What are the different DNA binding motifs
Helix-Turn-Helix, Zinc Fingers, Basic Domains, and Beta-scaffol factors
134
Steriod receptor is an example of a DNA binding protein which binds to ______ and functions as a _______ under the protein classification _____
HRE, Steroid Response, Zinc Finger
135
What are the two general transcription factors?
SP-1 and NF-1
136
TFIID is a kind of general transcription factor which binds to?
TATA box
137
In gluconeogenesis, the presence of glucagone and cortisol stimulates what gene?
PEPCK gene
138
True or False: Cortisol needs a receptor which increases cAMP levels in the cell?
FALSE
139
What is the difference of cortisol and glucagon in activating the PEPCK gene?
Cortisol diffuses directly into the cell and binds to the Glucocorticoid Response Element (GRE), while glucagon interacts indirectly through the use of secondary messengers after signal transuction
140
A permanent and heritable change in the DNA base seqeunce is called a _____
Mutation
141
Whare are the two classification of Mutations
Phenotypic effects and Type in Molecular Change
142
A type of mutation which is also known as null mutation?
Loss-of-Function
143
A type of mutation which produces a product with increased activity or a new function?
Gain-of-Function
144
A type of mutation where only one base of the DNA is altered that may result in the translation of a protein with abnormal amino acid sequences?
Point Mutations
145
Point mutations involves what?
Purine and Pyrimidine bases
146
Point mutation wherein a purine is replaced by another purine, or a pyrmidine to another pyrimidine
Transition
147
Point mutation wherein a purine is replaced by a pyrimidine
Transversion
148
Single-base substitutions are classified into?
Silent Mutation, Missense Mutation, and Nonsense Mutation
149
A type of single base substitution which results in the premature termination of transilation?
Nonsense Mutation
150
Silent Mutations are called silent because?
They cause no detectable effect
151
What type of single base substitution result in the translation of a different amino acid
Missense Mutation
152
Addition or deletion of 1 or more nucletorides are called?
Frameshift Mutation
153
True or False: Frameshift mutations result in the production of an entirely different protein after transcription and transliation
TRUE
