Test
Biochemistry undergrad quiz (still making)
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Preguntas del test (68)
1Viruses contain either DNA OR RNA
- AVerdadero
- BFalso
2A virus that is composed not of DNA but of RNA is called a [blank_start]retrovirus[blank_end]
- Aretrovirus
3Viroids are infectious agents without protein
- AVerdadero
- BFalso
4Prions –are infectious agents with both DNA and RNA
- AVerdadero
- BFalso
5Adenine and guanine are
- Apyrimidines
- Bpurines
6A nucleoside is formed when a
base is linked to the WHAT carbon of a
deoxyribose (or ribose) molecule- A1'
- B2'
- C3'
- D4'
7dCMP and dAMP are examples of [blank_start]nucleotides[blank_end]
- Anucleotides
- Bnucleosides
- Cproteins
- Dnucleic acid
8In DNA and RNA, nucleotides are linked by phosphodiester bonds between the [blank_start]5′[blank_end] and 3′ carbons
- A2'
- B3'
- C4'
- D5'
9In all prokaryotes and eukaryotes DNA is double-stranded
- AVerdadero
- BFalso
10Guanine 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.- A3
- B2
11Most or all cellular DNA is A-DNA
- AVerdadero
- BFalso
12Z-DNA is left handed and A-DNA is right handed
- AVerdadero
- BFalso
13Underwinding generates [blank_start]negative[blank_end] supercoils
Overwinding generates [blank_start]positive[blank_end] supercoils- Anegative
- Bpositive
14Single stranded DNA absorbs more UV than double
stranded DNA- AVerdadero
- BFalso
15UV absorbance rises as DNA
denatures is known as the [blank_start]hyperchromic shift[blank_end]- Ahyperchromic shift
16Tm (The temperature needed to denature
50% of the DNA molecules in a sample) is increased in DNA with high content of AT base-pairs- AVerdadero
- BFalso
17What are three key structural differences between
DNA and RNA?- ARNA has ribose instead of deoxyribose.
- BRNA has deoxyribose instead of ribose
- CRNA contains adenine, cytosine and guanine (like DNA) but has Uracil (U) instead of thymine.
- DRNA contains adenine, cytosine and guanine (like DNA) but has thymine (T) instead of uracil
- ERNA is usually double stranded
- FRNA is usually single stranded
18Plasmids carry non-essential genes, e.g. for
antibiotic resistance- AVerdadero
- BFalso
19Bacterial genomes usually consist of a single, linear chromosome made of double-stranded DNA
- AVerdadero
- BFalso
20Label this image
- AHeterochromatin
- BEuchromatin
21(Length of DNA/ Length of structure DNA packed into) is known as the [blank_start]packing ratio[blank_end]
- Apacking ratio
22By mass, the composition of a chromosome at mitosis is
approximately- A1/2 DNA and 1/2 histone proteins
- B1/3 DNA and 2/3 histone proteins
- C1/3 DNA, 1/3 histone proteins and 1/3 non histone proteins
- D1/2 DNA. 1/4 histone proteins and 1/4 non histone proteins
2320% of amino acids are arginine or lysine
- AVerdadero
- BFalso
24[blank_start]Condensin[blank_end] is a ring-shaped protein that can anchor the ends of a loop of DNA
- ACondensin
25[blank_start]topoisomerase II[blank_end] is an enzyme that can remove supercoils from DNA
- Atopoisomerase II
26Acetylation removes positive charge from side-chain and so [blank_start]weakens[blank_end]
interaction between histones and negatively-charged DNA- Astrengthens
- Bweakens
27Eukaryotic chromosomes have 1 origin of replication
- AVerdadero
- BFalso
28In bacterial replication, replication begins at a single AT-rich origin and is
bidirectional- AVerdadero
- BFalso
29What enzyme carries out transcriptase?
- AMaltase
- BDNA transcriptase
- CRNA
- DRNA polymerase
- EDNA helicase
30To synthesise RNA, RNA polymerases require:
- AA primer
- BA double stranded template DNA molecule that Includes
a promoter sequence - CAll four nucleoside triphosphates
31RNA polymerase binds to the promoter in the [blank_start]initiation[blank_end] stage
- Ainitiation
32RNA polymerase dissociates from DNA releasing
the new RNA molecule in the [blank_start]transcriptase[blank_end] stage- Atranscriptase
33RNA polymerase moves along the DNA molecule
synthesising an RNA copy in the [blank_start]elongation[blank_end] stage- Aelongation
34A [blank_start]consensus[blank_end] sequence is a sequence of DNA having similar structure and function in different organisms.
- Aconsensus
35The holoenzyme carries out elongation but not initiation
- AVerdadero
- BFalso
36Eukaryotic promoters differ from those in bacteria
- AVerdadero
- BFalso
37RNA 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- AI
- Bll
- Clll
- DI
- Ell
- Flll
- GI
- Hll
- Illl
38RNA polymerase II produces a 1° transcript (aka pre-mRNA)
which is processed in the nucleus to form mRNA. The main processing reactions are- AInitiation
- BRNA splicing
- CDNA splicing
- DCleavage and polyadenylation
- ECapping
- FDruining
39Promoters recognised by RNA polymerase II usually consists of a core promoter that may include a [blank_start]TATA[blank_end] box
- ATATA
- BTAAT
- CATAT
- DATTA
40RNA polymerases and DNA polymerases share the same mechanism.
- AVerdadero
- BFalso
41By mass, ribosomes have about a 1:2 ratio of rRNA to protein
- AVerdadero
- BFalso
42The size of ribosomes is measured in Svedbergs (S)
- sedimentation rate during centrifugation.- AVerdadero
- BFalso
43The small subunit on a ribosome catalyses peptide bond formation, the
large subunit binds the mRNA being translated- AVerdadero
- BFalso
44mRNA is read from
- A5' to 3'
- B3' to 5'
45The small (30S) ribosome subunit binds to the ribosome
binding site on the mRNA in E.Coli- AVerdadero
- BFalso
46There are several ribosome binding sites on mRNA in eukaryotes
- AVerdadero
- BFalso
47A sequence has [blank_start]three[blank_end] possible reading frames depending
on where translation starts from- Athree
- Bone
- Ctwo
- Dfour
48The region between an initiation codon (AUG) and a
termination codon is an“open-reading frame”- AVerdadero
- BFalso
49How do amino acids recognise codons?
Adaptor molecules deliver amino acids to the appropriate codons. These adaptors are transfer RNAs- AVerdadero
- BFalso
50How long are tRNAs?
- ALarge: 220-293 nucleotides long
- BSmall: 50-73 nucleotides long
- CSmall: 73-90 nucleotides long
- DLarge: 320-393 nucleotides long
51All tRNAs have an anticodon
- AVerdadero
- BFalso
52All tRNAs have the sequence GCA at their 3' end.
- AVerdadero
- BFalso
53the 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]
- Abase wobble
54The enzymes that link tRNAs to amino acids are called
- Aaminoakyl-tRNA synthetases.
- Baminoacyl-tRNA synthetases.
- Caminoacyl-rRNA synthetases.
- Daminoakyl-rRNA synthetases.
55The classic example of inducible genes are the three genes required for utilisation of lactose by E. coli. These are:
- ALac Z gene
- BLac B gene
- CLac A gene
- DLac Y gene
- ELac T gene
56The [blank_start]operator[blank_end] is the binding
site for lac repressor
protein.- Aoperator
57The Lac [blank_start]i[blank_end] gene encodes the
Lac repressor protein.- Ai
58Transcription of the genes of the lac operon is repressed by the lac [blank_start]repressor[blank_end] protein
- Arepressor
59When lactose is absent, the lac repressor protein binds to the promoter
- AVerdadero
- BFalso
60When the lac repressor protein is bound to the operator,
RNA polymerase can still bind to the promoter but cannot
initiate transcription.- AVerdadero
- BFalso
61When lactose is present some is
converted into an isomer called
[blank_start]allolactose[blank_end].- Aallolactose
62Allolactose binds to the lac repressor protein inducing a conformational change so that lac repressor cannot bind to operator.
- AVerdadero
- BFalso
63Lactose 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
- ACatabolite
64Removal of catabolite repression requires:
- AThe Catabolite Activator Protein (CAP)
- BcAMP
- CATP
- DLac i gene
65When glucose conc’ is high the cAMP conc’ is low
- AVerdadero
- BFalso
66[blank_start]Monosaccharides[blank_end] are colourless, crystalline solids, water soluble and most are sweet tasting.
- AMonosaccharides
- BPolysaccharides
- COligosaccharides
67In general, a molecule with n chiral centres can have [blank_start]2[blank_end]n stereoisomers
- A2
- B1
- C3
- D4
68[blank_start]Epimers[blank_end]: each of two isomers with different configurations of atoms about one of several asymmetric carbon atoms present
- AEpimers
Información
- Descripción
- Biochemistry Test sobre Biochemistry undergrad quiz (still making), creado por Lily O el 14/12/2019.
- Autor
- Lily O
- Idioma
- English
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- 27
- Etiquetas
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