Semester 2 Flashcards
(149 cards)
1
Q
What is the stop codon in mRNA for Translation?
A
UGA
2
Q
What does dATP stand for?
A
2’- deoxyadenosine-5’ - triphosphate
3
Q
How many copies of the rRNA genes are there in the human genome?
A
200
4
Q
Proteome refers to the entire … population of a cell.
A
Protein
5
Q
The reason UV light damages DNA is…
A
The wavelength of UV light overlaps with the absorption spectrum of DNA.
6
Q
What is INCORRECT in regards to PCR?
A
PCR is required to cut out specific genes for cloning
7
Q
The 5’ end of an mRNA contains a… and the 3’ end contains a…
Both of these modifications … the … of a eukaryotic mRNA.
A
7-Methyl G cap
Poly-A tail
Increase
Stablity
8
Q
What is INCORRECT with regards to the Alpha Helix in a protein?
A
Amino acid side chains project inward abd upward from the helix
9
Q
The rod like structures resulting from the hydrogen bonding every 4th peptide bond is known as…
A
Alpha Helix
10
Q
The 2 strands of DNA double helix are held together by…
A
Hydrogen bonds
11
Q
What is the MOST abundant RNA species in a cell?
A
rRNA
12
Q
Anti-parallell nature of DNA refers to…
A
Both DNA strands run in opposite direction
13
Q
Recombinant DNA is formed by the…
A
Ligation of DOUBLE stranded insert with DOUBLE stranded vector
14
Q
During Translation, the combined function of IF1 and IF3 is to…
A
Prevent premature assesmbly of ribosome.
15
Q
Which enzyme causes DNA melting ahead of the replication fork?
A
Helicase
16
Q
During DNA replication, the DNA ligase enzyme joins Okazaki fragments on lagging strands by catalysing…
A
The formation of a phosphodiester bond between 5’phosphate and 3’ hydroxyl of the adjacent Okzazaki fragments
17
Q
Melting of DNA results in decreased … at … temperatures.
This is caused by the disruption of … bonds between the 2 strands.
A
Viscosity
High
Hydrogen
18
Q
A nucleotide is composed of a … sugar, a … base and a … group.
A
Pentose
Nitrogenous
Phosphate
19
Q
Sequence specific DNA cutting enzymes used in the creation of recombinant DNA are commonly known as…
A
Restriction Endonucleases
20
Q
During the process of Translation, charged tRNA molecules enter the ribosome through…
A
A site
21
Q
Plasmid vectors are commonly used as cloning vectors. What is INCORRECT about them?
A
Plasmids have been engineered to replicate in human cells
22
Q
Acyclovir and Zidovudine are drugs used for viral infections. They function by…
A
Inhibiting DNA synthesis
23
Q
EcoRI cleaves DNA at…
A
G AATTC
24
Q
Even the smallest amount of DNA obtained from samples collected at crime scenes can be multiplied into MILLIONS of copies by using a technique called…
A
Polymerase chain reaction
25
A generically modified organism means an organism has had genes…
Replaced!
26
MicroRNAs and siRNAs act through which of the following mechanisms?
RNA Interference
27
The central dogma of molecular biology does NOT address…
Carbohydrates
28
In prokaryotes, RNA polymerase core enzymes PLUS sigma factor form the RNA polymerase holoenzyme.
The function of this sigma factor is…
Promoter recognition
29
Hyperchromic effect will be more pronounced when…
DNA has a very high A:T content
30
What is NOT a known RNA molecule?
zRNA
31
What is a protein that is involved in Translation?
Aminoacyl- tRNA Synthetase
32
Codons UAG, UAA and UGA are recognised by?
Release factor
33
Chargaff’s rule proved that…
DNA has equimolar ratio of Adenine and Thymine
34
Phosphodiester bonds are formed in this direction…
5’ - 3’
35
Silent mutation results in…
Change of DNA sequence WITHOUT changing the amino acid sequence
36
Terminal deoxynucleotodyl transferase is commonly used in cloning to generate…
3’ sticky ends
37
Genetic engineering is…
Transfer of DNA from 1 organism to another
38
Disulfide bond formation involves…
Oxidation of 2 cysteines to form s-s bond
39
The genetic code is the language in the … which has … letters and … words and the language is read by…
mRNA
Four
Sixty one
tRNA
40
What is INCORRECT in regards to the function of RNA polymerase?
It is a Nucleotidyl transferase that catalyses linkage of 2’ deoxyribonucleotides.
41
What is CORRECT about the genetic code?
The genetic code is degenerate
42
What is INCORRECT about DNA polymerase enzyme?
Essential for RNA replication
43
The mRNA code is read by…
tRNA
44
The … folding of a … chain can give rise to … such as helix and … sheets
```
Local
Peptide
Secondary
Alpha
Beta
```
45
Who is accredited with the concept of double stranded nature of DNA?
Watson + Crick
46
What is INCORRECT about the genetic code?
ALL codons specify MORE THAN ONE amino acid
47
The enzyme that requires ATP to break hydrogen bonds between bases to open up DNA ahead of the Replication Fork is called…
Helicase
48
Prokaryotic ribosomes (70S) are made up of…
TWO subunits of 50S and 30S
49
What is NOT a pyrimidine base?
Adenine
50
What is FALSE about Telomerase?
It extends the 3’ end of the leading strand
51
What is FALSE about genomes?
Gene density is HIGHER in eukaryotes than in prokaryotes
52
What % of the DNA in the human genome represents Protein Coding Regions?
1.5 %
53
What is the approx. % of alternatively spliced human genes?
90%
54
What are satellites in the genome?
14 - 1000 bp tandem repeats of DNA
55
What is a pseudogene?
Non- functional copy of a gene
56
What pairs of genes / proteins are considered to be orthologus?
Yeast a-tublin and worm a-tubulin
57
What is chromatin?
DNA and histone proteins
58
Nucleosome cores DO NOT contain…
Histone H9
59
What is a key feature of chromosomes?
Centromere
60
Number of human chromosomes in haploid cells is…
23
61
What is FALSE in regards to Giemsa staining?
It is used for the detection of single nucleotide chromosomal mutations
62
2 genes may have a similar function if they share HIGH…
Homology
63
How is sequence analysis useful?
```
Organism identification
Protein domains and function
Gene prediction
Evolution and philogenetics
TF binding sites
Protein families
```
64
When aligning 2 highly similar sequences which aligner is the most appropriate?
Pairwise global
65
What type of aligner is BLAST?
Local pairwise
66
What is a permanent change in a gene?
Mutation
67
What is the ploidy of a gamete?
Haploid
68
What is the genotype of an F1 hybrid?
Heterozygous
69
What is the phenotype of an F1 hybrid?
Dominant
70
What is the F2 frequency of the dominant and recessive phenotypes?
75% dominant and 25% recessive
71
Alleles in different chromosomes are…
Inherited separately
72
In order to suffer from Huntington disease (dominant monogenic) and the individual must have…
At least 1 of parents must be affected
73
To suffer from cystic fibrosis (monogenic recessive) individual must have…
Both parents that are carriers
74
A male will suffer from haemophilia (x- linked recessive) if…
His mother is AT LEAST a carrier
75
What is the genotype of a true- breeding organism?
Homozygote
76
Alleles in the opposite extremes of the same chromosomes are…
Inherited separately
77
In the absence of lactose and presence of glucose, the expression of genes in the lac operon is:
Negligible / repressed
78
In the presence of BOTH lactose and presence of glucose, the expression of genes in the lac operon is:
Low expression
79
In the absence of glucose and presence of lactose, the expression of genes in the lac operon is:
Maximal expression
80
Actin is an essential cytoskeleton protein that determines the shape of cells.
How is it transcribed?
By RNA pol II and a weak broad promoter ( CpG island)
81
18S is an essential RNA constituent of ribosomes. How is it transcribed?
By RNA Pol I and a weak dispersed promoter (CpG island)
82
How do you think Tumour Necrosis Factor (TNF) is transcribed?
By RNA pol II and a strong sharp promoter (TATA box and / or initiator element)
83
What is BRE?
TFIIB recognition element
84
What is the role of TFIIC in the pre- initiation complex?
There is NOT TFIIC in the pre initiation complex!
85
What is NOT a structural motif found in a DNA binding domain?
Random coiled acidic domain
86
What is the function of Mediator?
Act as a molecular bridge between transcription factors and the RNA polymerase
87
The estrogen receptor…
Is inactive in the cystol in resting cells
88
What histones have only N-terminal tails?
H2A and H2B
89
What does H3K27me3 mean?
Tri methylation of Lysine 27 on Histone 3
90
What are the members of the steroid receptor or nuclear receptor superfamily?
Zinc Finger Proteins
91
What histone modification typically associates with Euchromatin?
Acetylation
92
How would you identify genomic sequences modulating transcriptional activity?
By recombinant DNA technologies and reporter gene assays
93
Epi genetic repression of gene transcription can occur through…
Histone methylation
94
What is Gene Ontology?
A fixed language for describing gene function
95
KEGG is a great database for…
Metabolic pathways
96
A good database for obtaining functional information is…
GO
97
What is NOT one of the three domains of Gene Ontology?
Enzyme classification
98
What does Uniprot database store?
Curated and predicated amino acid sequences
99
What is NOT a fixed format / language?
Uniprot
100
What information is needed to univocally find a biological entity in a database?
Unique identifier
101
What best describes the FastA format?
Fixed format for sequence information
102
BLAST can be used to…
Look for sequence homology
103
A statistically significant BLAST result will always have…
An E- value less than threshold (typically <0.001)
104
What statement is FALSE regarding local sequence alignment?
Align sequences end to end
105
What is NOT an application for multiple sequence alignment?
Detect regions of Analogy in multiple sequences
106
In the context of Genomics, collinearity between 2 species is…
A set of homologous genes located in the SAME chromosome in the SAME order
107
Analogy between 2 species relates to…
The sharing of a similar trait by Convergent Evolution
108
How many copies of an mRNA are usually present (= median value) in a human cell?
17
109
What is a RNA binding domain?
RRM
110
Capping of mRNAs occurs in…
The nucleus
111
Polyadenylation is a 2 step process involving…
Cleavage and polyadenylation
112
What kind of chemical reactions happen during pre-mRNA splicing?
Transesterification
113
Pre-mRNA splicing in eukaryotes involves small RNAs called…
snRNAs
114
mRNA localisation: which of the following statements is FALSE?
mRNA localisation is unique in eukaryotes
115
Translation regulation on mRNAs can be inferred by?
RNA binding proteins interacting with UTRs
RNA structures present in UTRs or elsewhere
Small non coding RNAs such as miRNAs
Translation initiation factors
116
MicroRNAs…
Repress gene expression post- transcriptionally
117
Which of the following is TRUE in regards to siRNAs?
Fully base pair with target mRNA in cytoplasm
118
Xrn1…
Degrades RNA in 5’ to 3’ direction
119
List the correct sequence of steps involved in Gene Cloning:
1. Isolation of the desired gene
2. Insertion of the isolated gene to the vector
3. Introduction of the recombinant vector to the Host
4. Expression of the recombinant gene in Host
5. Extraction of the recombinant gene product.
120
What eukaryotic transcription factor phosphorylates RNA polymerase 2?
TFIIH
121
What type of DNA binding domain is present in the nuclear receptor superfamily?
Zinc finger domain with 4 cysteine residues
122
What types of post translational modifications can be identified in histones?
Acetylation
Methylation
Phosphorylation
Ubiquitylation
123
What is the cooperative binding of several transcription factors on a transcriptional element called?
Enhanceosome
124
Bacterial promoters contain areas bound by RNA polymerase known as…
-10 and -35 boxes
125
Zinc finger domains are…
DNA binding domains
126
The prokaryotic RNA polymerase holoenzyme is…
The processive core PLUS sigma factor
127
What is FALSE about TATA boxes and initiator elements?
Most eukaryotic genes are controlled by TATA boxes or initiator elements
128
What is correct regarding the pre initiation complex?
Multiple transcription factors are needed to create it in eukaryotes
The 1st transcription factor that initiates it has DNA binding capacity
The LAST transcription factor that is recruited has Kinase activity
RNA polymerase 2 joins the promoter element in INACTIVE form
129
What eukaryotic transcription factor fixes TFIID on DNA?
TFIIB
130
What is FALSE regarding bacterial operons?
Encompasses multiple promoters
131
What is FALSE about the TATA binding protein TBP?
All general transcription factors GTFs BUT TBP remain attached to promoter to allow new mRNA synthesis
132
TATA boxes are…
Strong promoters controlling expression of inducbile genes
133
A critical stretch of phosphorylated amino acids that is essential to support life is present in the…
Beta subunit 1 of RNA polymerase 2
134
Hyperacetylation of the histone tails results in…
Promoter activation
135
How is the gene interferon B controlled at the transcriptional level?
By RNA pol 2 and a strong promoter
136
How do we define a eukaryotic transcription factor?
A protein with DNA binding activity that impacts on transcriptional activity
137
What eukaryotic RNA polymerases produce protein coding RNA and tRNA respectively?
RNA pol 2 and RNA pol 3
138
What is correct about prokaryotic gene expression?
Bacterial genes are polycistronic
139
How does estrogen activate gene expression?!
It induces the translocation of the estrogen receptor into the nucleus
140
What elements are needed to form the pre initiation complex?
RNA pol 2
General transcription factors
DNA promoter
141
What is correct about enhancers and promoter proximal elements?
Their location upstream of the transcription start site is DIFFERENT
142
In the presence of glucose, the lac operon is…
Repressed as long as it can neutralise cAMP, Lacl is active, CAP is not active
Repressed unless lactose is present
143
What is correct regarding transcription elongation in prokaryotes?
Transcription elongation is chiefly controlled by Riboswitches
144
Yeast two hybrids is a common technique used to assess…
Interactions between proteins
145
In the presence of lactose, the lac operon…
Is activated as long as it can repress Lacl and CAP is activated
Is activated unless glucose is present and cAMP is neutralised
146
What is true about eukaryotic gene transcription?
Eukaryotes have sophisticated mechanisms to control transcription at the initiation level
147
A polycistronic transcript is…
Derived from multiple genes
Encodes for multiple proteins
NOT found in eukaryotic cells
Derived from 1 promoter element
148
Where do eukaryotic promoters locate?
Depends on the gene
149
What is FALSE regarding nuclear receptor superfamily transcription factors?
They are conserved in ALL eukaryotes
