20469804
Pregunta 1
Pregunta
Viruses contain either DNA OR RNA
Respuesta
- True
- False
Pregunta 2
Pregunta
A virus that is composed not of DNA but of RNA is called a [blank_start]retrovirus[blank_end]
Respuesta
-
retrovirus
Pregunta 3
Pregunta
Viroids are infectious agents without protein
Respuesta
- True
- False
Pregunta 4
Pregunta
Prions –are infectious agents with both DNA and RNA
Respuesta
- True
- False
Pregunta 5
Pregunta
Adenine and guanine are
Respuesta
-
pyrimidines
-
purines
Pregunta 6
Pregunta
A nucleoside is formed when a
base is linked to the WHAT carbon of a
deoxyribose (or ribose) molecule
Respuesta
-
1'
-
2'
-
3'
-
4'
Pregunta 7
Pregunta
dCMP and dAMP are examples of [blank_start]nucleotides[blank_end]
Respuesta
-
nucleotides
-
nucleosides
-
proteins
-
nucleic acid
Pregunta 8
Pregunta
In DNA and RNA, nucleotides are linked by phosphodiester bonds between the [blank_start]5′[blank_end] and 3′ carbons
Respuesta
-
2'
-
3'
-
4'
-
5'
Pregunta 9
Pregunta
In all prokaryotes and eukaryotes DNA is double-stranded
Respuesta
- True
- False
Pregunta 10
Pregunta
Guanine and Cytosine form a base-pair held together by [blank_start]3[blank_end] hydrogen bonds.
Adenine and Thymine form a base-pair held together by [blank_start]2[blank_end] hydrogen bonds.
Respuesta
-
3
-
2
Pregunta 11
Pregunta
Most or all cellular DNA is A-DNA
Respuesta
- True
- False
Pregunta 12
Pregunta
Z-DNA is left handed and A-DNA is right handed
Respuesta
- True
- False
Pregunta 13
Pregunta
Underwinding generates [blank_start]negative[blank_end] supercoils
Overwinding generates [blank_start]positive[blank_end] supercoils
Respuesta
-
negative
-
positive
Pregunta 14
Pregunta
Single stranded DNA absorbs more UV than double
stranded DNA
Respuesta
- True
- False
Pregunta 15
Pregunta
UV absorbance rises as DNA
denatures is known as the [blank_start]hyperchromic shift[blank_end]
Respuesta
-
hyperchromic shift
Pregunta 16
Pregunta
Tm (The temperature needed to denature
50% of the DNA molecules in a sample) is increased in DNA with high content of AT base-pairs
Respuesta
- True
- False
Pregunta 17
Pregunta
What are three key structural differences between
DNA and RNA?
Respuesta
-
RNA has ribose instead of deoxyribose.
-
RNA has deoxyribose instead of ribose
-
RNA contains adenine, cytosine and guanine (like DNA) but has Uracil (U) instead of thymine.
-
RNA contains adenine, cytosine and guanine (like DNA) but has thymine (T) instead of uracil
-
RNA is usually double stranded
-
RNA is usually single stranded
Pregunta 18
Pregunta
Plasmids carry non-essential genes, e.g. for
antibiotic resistance
Respuesta
- True
- False
Pregunta 19
Pregunta
Bacterial genomes usually consist of a single, linear chromosome made of double-stranded DNA
Respuesta
- True
- False
Pregunta 20
Respuesta
-
Heterochromatin
-
Euchromatin
Pregunta 21
Pregunta
(Length of DNA/ Length of structure DNA packed into) is known as the [blank_start]packing ratio[blank_end]
Respuesta
-
packing ratio
Pregunta 22
Pregunta
By mass, the composition of a chromosome at mitosis is
approximately
Respuesta
-
1/2 DNA and 1/2 histone proteins
-
1/3 DNA and 2/3 histone proteins
-
1/3 DNA, 1/3 histone proteins and 1/3 non histone proteins
-
1/2 DNA. 1/4 histone proteins and 1/4 non histone proteins
Pregunta 23
Pregunta
20% of amino acids are arginine or lysine
Respuesta
- True
- False
Pregunta 24
Pregunta
[blank_start]Condensin[blank_end] is a ring-shaped protein that can anchor the ends of a loop of DNA
Respuesta
-
Condensin
Pregunta 25
Pregunta
[blank_start]topoisomerase II[blank_end] is an enzyme that can remove supercoils from DNA
Respuesta
-
topoisomerase II
Pregunta 26
Pregunta
Acetylation removes positive charge from side-chain and so [blank_start]weakens[blank_end]
interaction between histones and negatively-charged DNA
Respuesta
-
strengthens
-
weakens
Pregunta 27
Pregunta
Eukaryotic chromosomes have 1 origin of replication
Respuesta
- True
- False
Pregunta 28
Pregunta
In bacterial replication, replication begins at a single AT-rich origin and is
bidirectional
Respuesta
- True
- False
Pregunta 29
Pregunta
What enzyme carries out transcriptase?
Respuesta
-
Maltase
-
DNA transcriptase
-
RNA
-
RNA polymerase
-
DNA helicase
Pregunta 30
Pregunta
To synthesise RNA, RNA polymerases require:
Respuesta
-
A primer
-
A double stranded template DNA molecule that Includes a promoter sequence
-
All four nucleoside triphosphates
Pregunta 31
Pregunta
RNA polymerase binds to the promoter in the [blank_start]initiation[blank_end] stage
Respuesta
-
initiation
Pregunta 32
Pregunta
RNA polymerase dissociates from DNA releasing
the new RNA molecule in the [blank_start]transcriptase[blank_end] stage
Respuesta
-
transcriptase
Pregunta 33
Pregunta
RNA polymerase moves along the DNA molecule
synthesising an RNA copy in the [blank_start]elongation[blank_end] stage
Respuesta
-
elongation
Pregunta 34
Pregunta
A [blank_start]consensus[blank_end] sequence is a sequence of DNA having similar structure and function in different organisms.
Respuesta
-
consensus
Pregunta 35
Pregunta
The holoenzyme carries out elongation but not initiation
Respuesta
- True
- False
Pregunta 36
Pregunta
Eukaryotic promoters differ from those in bacteria
Respuesta
- True
- False
Pregunta 37
Pregunta
RNA polymerase [blank_start]I[blank_end] - synthesises rRNA
RNA polymerase [blank_start]III[blank_end] - synthesises tRNA
RNA polymerase [blank_start]II[blank_end] - synthesises mRNA
Respuesta
-
I
-
ll
-
lll
-
I
-
ll
-
lll
-
I
-
ll
-
lll
Pregunta 38
Pregunta
RNA polymerase II produces a 1° transcript (aka pre-mRNA)
which is processed in the nucleus to form mRNA. The main processing reactions are
Respuesta
-
Initiation
-
RNA splicing
-
DNA splicing
-
Cleavage and polyadenylation
-
Capping
-
Druining
Pregunta 39
Pregunta
Promoters recognised by RNA polymerase II usually consists of a core promoter that may include a [blank_start]TATA[blank_end] box
Respuesta
-
TATA
-
TAAT
-
ATAT
-
ATTA
Pregunta 40
Pregunta
RNA polymerases and DNA polymerases share the same mechanism.
Respuesta
- True
- False
Pregunta 41
Pregunta
By mass, ribosomes have about a 1:2 ratio of rRNA to protein
Respuesta
- True
- False
Pregunta 42
Pregunta
The size of ribosomes is measured in Svedbergs (S)
- sedimentation rate during centrifugation.
Respuesta
- True
- False
Pregunta 43
Pregunta
The small subunit on a ribosome catalyses peptide bond formation, the
large subunit binds the mRNA being translated
Respuesta
- True
- False
Pregunta 44
Pregunta
mRNA is read from
Respuesta
-
5' to 3'
-
3' to 5'
Pregunta 45
Pregunta
The small (30S) ribosome subunit binds to the ribosome
binding site on the mRNA in E.Coli
Respuesta
- True
- False
Pregunta 46
Pregunta
There are several ribosome binding sites on mRNA in eukaryotes
Respuesta
- True
- False
Pregunta 47
Pregunta
A sequence has [blank_start]three[blank_end] possible reading frames depending
on where translation starts from
Respuesta
-
three
-
one
-
two
-
four
Pregunta 48
Pregunta
The region between an initiation codon (AUG) and a
termination codon is an“open-reading frame”
Respuesta
- True
- False
Pregunta 49
Pregunta
How do amino acids recognise codons?
Adaptor molecules deliver amino acids to the appropriate codons. These adaptors are transfer RNAs
Respuesta
- True
- False
Pregunta 50
Pregunta
How long are tRNAs?
Respuesta
-
Large: 220-293 nucleotides long
-
Small: 50-73 nucleotides long
-
Small: 73-90 nucleotides long
-
Large: 320-393 nucleotides long
Pregunta 51
Pregunta
All tRNAs have an anticodon
Respuesta
- True
- False
Pregunta 52
Pregunta
All tRNAs have the sequence GCA at their 3' end.
Respuesta
- True
- False
Pregunta 53
Pregunta
the ability of some bases at 5' end of anticodon to pair with more than one base at 3' end of codon is known as the [blank_start]base wobble[blank_end]
Respuesta
-
base wobble
Pregunta 54
Pregunta
The enzymes that link tRNAs to amino acids are called
Respuesta
-
aminoakyl-tRNA synthetases.
-
aminoacyl-tRNA synthetases.
-
aminoacyl-rRNA synthetases.
-
aminoakyl-rRNA synthetases.
Pregunta 55
Pregunta
The classic example of inducible genes are the three genes required for utilisation of lactose by E. coli. These are:
Respuesta
-
Lac Z gene
-
Lac B gene
-
Lac A gene
-
Lac Y gene
-
Lac T gene
Pregunta 56
Pregunta
The [blank_start]operator[blank_end] is the binding
site for lac repressor
protein.
Respuesta
-
operator
Pregunta 57
Pregunta
The Lac [blank_start]i[blank_end] gene encodes the
Lac repressor protein.
Respuesta
-
i
Pregunta 58
Pregunta
Transcription of the genes of the lac operon is repressed by the lac [blank_start]repressor[blank_end] protein
Respuesta
-
repressor
Pregunta 59
Pregunta
When lactose is absent, the lac repressor protein binds to the promoter
Respuesta
- True
- False
Pregunta 60
Pregunta
When the lac repressor protein is bound to the operator,
RNA polymerase can still bind to the promoter but cannot
initiate transcription.
Respuesta
- True
- False
Pregunta 61
Pregunta
When lactose is present some is
converted into an isomer called
[blank_start]allolactose[blank_end].
Respuesta
-
allolactose
Pregunta 62
Pregunta
Allolactose binds to the lac repressor protein inducing a conformational change so that lac repressor cannot bind to operator.
Respuesta
- True
- False
Pregunta 63
Pregunta
Lactose breakdown is only necessary if glucose is not available. Therefore when both lactose and glucose are present in environment, lac operon genes only transcribed weakly. This effect is called [blank_start]Catabolite[blank_end] Repression
Respuesta
-
Catabolite
Pregunta 64
Pregunta
Removal of catabolite repression requires:
Respuesta
-
The Catabolite Activator Protein (CAP)
-
cAMP
-
ATP
-
Lac i gene
Pregunta 65
Pregunta
When glucose conc’ is high the cAMP conc’ is low
Respuesta
- True
- False
Pregunta 66
Pregunta
[blank_start]Monosaccharides[blank_end] are colourless, crystalline solids, water soluble and most are sweet tasting.
Respuesta
-
Monosaccharides
-
Polysaccharides
-
Oligosaccharides
Pregunta 67
Pregunta
In general, a molecule with n chiral centres can have [blank_start]2[blank_end]n stereoisomers
Respuesta
-
2
-
1
-
3
-
4
Pregunta 68
Pregunta
[blank_start]Epimers[blank_end]: each of two isomers with different configurations of atoms about one of several asymmetric carbon atoms present
Respuesta
-
Epimers
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