extra biochem Q's (midterm) Flashcards
Which of the following histone proteins doesn’t participate in forming an octamer protein complex?
a. H1
b. H2A
c. H2B
d. H3
e. H4
a. H1
Which of the following is the function of H1 histone protein?
a. 10-bp linker nucleotide stabilization
b. 30-bp linker nucleotide stabilization
c. 50-bp linker nucleotide stabilization
b. 30-bp linker nucleotide stabilization
Which of the following required cooling?
a. denaturation
b. melting temperature
c. renaturation
c. renaturation
In which of the following is half of the DNA denatured?
a. denaturation
b. melting temperature
c. renaturation
b. melting temperature
Which of the following has a higher melting temperature?
a. G-C rich DNA
b. A-T rich DNA
a. G-C rich DNA
because the G-C bond has 3 hydrogen bonds unlike the A-T which have two
What’s true about prokaryotic gene?
a. they don’t have a promoter region
b. they don’t have introns
b. they don’t have introns
What percent of the human genome is repetitive sequences?
a. 33%
b. 47%
c. 53%
b. 47%
Which best describes Alu elements?
a. promote gene inactivation
b. promote gene activation
a. promote gene inactivation
they do this by inserting themselves in or near genes
Where do Alu elements belong?
a. LINEs
b. SINEs
c. LTR
d. Satelight DNA
b. SINEs
Which of the following does the DnaA protein bind to so it can separate the DNA?
a. replication fork
b. satellite region
c. origin of replication
c. origin of replication
What best describes the origin of replication?
a. recognized by helicase
b. has A-T rich sequences
c. needs cool temperature to open
b. has A-T rich sequences
Which of the following is the function of single stranded binding proteins?
a. protects DNA from nuclease degradation
b. helps keep the two DNA strands separate
c. both
d. neither
c. both
What is FALSE about helicase?
a. binds to origin of replication
b. breaks hydrogen bonds
c. uses ATP for energy
a. binds to origin of replication
it binds to the replication fork created by DNA A
Which of the following relaxes the supercoiled DNA?
a. helicase
b. topoisomerase
c. DNA polymerase III
d. primase
b. topoisomerase
Which of the following is a holoenzyme?
a. helicase
b. topoisomerase
c. DNA polymerase III
d. primase
c. DNA polymerase III
Which of the following is the acceptor site of RNA primer?
a. 5-OH
b. 3-OH
c. 3’-OH
d. 5’-OH
c. 3’-OH
Which characterizes the lagging strand?
a. goes in the 3->5 direction
b. needs one RNA primer
c. synthesized in the direction towards the replication fork
d. synthesized in the direction opposite to the replication fork
d. synthesized in the direction opposite to the replication fork
(its made in the 5’->3’ direction by using many RNA primers)
Which of the following DNA polymerase III subunit proofreads?
a. α subunit
b. θ subunit
c. ε subunit
c. ε subunit
proofreads in the 3’->5’ direction
Which of the following fills in the DNA gap made by the RNA primer in the prokaryotic cell?
a. DNA polymerase I
b. DNA ligase
c. polymerase ε
d. exonuclease
a. DNA polymerase I
Which of the following fills in the DNA gap made by the RNA primer in the eukaryotic cell?
a. DNA polymerase I
b. DNA ligase
c. polymerase ε
d. exonuclease
c. polymerase ε
What’s true about telomerase?
a. acts as RNA primer
b. acts as a reverse transcriptase
c. active in all cells
b. acts as a reverse transcriptase
What exonuclease activity does the prokaryotic DNA Polymerase I have?
a. 5’->3’
b. 3’->5’
c. both
c. both
What exonuclease activity does the prokaryotic DNA Polymerase III have?
a. 5’->3’
b. 3’->5’
c. both
b. 3’->5’
Didanosine is an analog of
a. Guanosine
b. Adenosine
c. Thymidine
d. Adenine
b. Adenosine
Zidovudine is an analog of
a. Guanosine
b. Adenosine
c. Thymidine
d. Adenine
c. Thymidine
Zidovudine= Azidothymidine
Camptothecin (CPT) inhibits which of the following?
a. ligase
b. topoisomerase I
c. topoisomerase II
d. DNA polymerase
b. topoisomerase I
Etoposide inhibits which of the following?
a. ligase
b. topoisomerase I
c. topoisomerase II
d. DNA polymerase
c. topoisomerase II
Depurination and deamination both occur because of what reaction?
a. oxidation reaction
b. hydrolysis reaction
c. transversion mutation
b. hydrolysis reaction
What type of mutation does depurination cause?
a. deletion mutation
b. transition mutation
c. transversion mutation
a. deletion mutation
What type of mutation does deamination cause?
a. deletion mutation
b. transition mutation
c. transversion mutation
b. transition mutation
cytosine to thymine
What type of mutation does ROS mediated damage cause?
a. deletion mutation
b. transition mutation
c. transversion mutation
c. transversion mutation
= a (two ring) purine is changed for a (one ring) pyrimidine, or vice versa
What type of mutation does a tautomeric shift cause?
a. deletion mutation
b. transition mutation
b. transition mutation
Which of the following is an example of structural DNA damage?
a. deamination
b. depurination
c. thymine dimers
d. tautomeric shift
c. thymine dimers
Which of the following mutations cause an amino acid change?
a. missense
b. nonsense
c. makesense
d. silent mutation
a. missense
Which of the following mutations causes the synthesis of a completely different protein?
a. missense
b. nonsense
c. frameshift mutation
d. silent mutation
c. frameshift mutation
Which of the following corrects deamination mutation?
a. mismatch repair
b. base excision repair
c. nucleotide excision repair
b. base excision repair
Which of the following corrects pyrimidine dimes?
a. mismatch repair
b. base excision repair
c. nucleotide excision repair
c. nucleotide excision repair
Which of the following repair system failures is responsible for Ataxia-telangiectasia mutation (ATM)?
a. mismatch repair
b. base excision repair
c. nucleotide excision repair
b. base excision repair
Which of the following repair system failures is responsible for hereditary nonpolyposis colon cancer?
a. mismatch repair
b. base excision repair
c. nucleotide excision repair
a. mismatch repair
Which of the following repair system failures is responsible for xeroderma pigmentosum (XP)?
a. mismatch repair
b. base excision repair
c. nucleotide excision repair
c. nucleotide excision repair
What is the function fo Taq DNA Polymerase?
a. create cDNA
b. make the DNA more stable so it doesn’t denature
c. hold the DNA open for the replicating enzymes to work
b. make the DNA more stable so it doesn’t denature
Taq= Thermus aquaticus
how many PCR cycles does it take to get the target sequence to appear?
a. 3
b. 4
c. 5
d. 8
a. 3
If you have one initial substrate, how many PCR cycles does it take to make 16 products?
a. 2
b. 4
c. 6
d. 8
b. 4
product= (2)^number of cycles
The annealing temperature (Tm) depends on primer size. What temperature is necessary for annealing this sequence “ACA ATG”?
a. 14
b. 16
c. 18
d. 20
b. 16
Tm=2x(# of AT) + 4x(# of CG)
Which of the following terminates DNA synthesis?
a. dNTP
b. ddNTP
c. dCTP
d. dTTP
b. ddNTP
which of the following has a red dye?
a. ddATP
b. ddGTP
c. ddCTP
d. ddTTP
d. ddTTP
which of the following has a black dye?
a. ddATP
b. ddGTP
c. ddCTP
d. ddTTP
b. ddGTP
T/F: amplification of sanger’s method geometrically progressive
False, the method only uses one primer, so it cannot grow exponentially
which of the following has a green dye?
a. ddATP
b. ddGTP
c. ddCTP
d. ddTTP
a. ddATP
what defines the target sequence of PCR?
a. the dye
b. the primer
c. dNTP
b. the primer
which of the following has a blue dye?
a. ddATP
b. ddGTP
c. ddCTP
d. ddTTP
c. ddCTP
Which of the following is the smallest?
a. tRNA
b. rRNA
c. mRNA
a. tRNA
Which of the following is the most heterogeneous type (can have varying lengths)?
a. tRNA
b. rRNA
c. mRNA
c. mRNA
Which of the following is the most common?
a. tRNA
b. rRNA
c. mRNA
b. rRNA
Which of the following is more active?
a. euchromatin
b. heterochromatin
a. euchromatin
Which of the following is more positive?
a. euchromatin
b. heterochromatin
b. heterochromatin
Which of the following is a pre-requisite for mRNA?
a. RNA polymerase I
b. RNA polymerase II
c. RNA polymerase III
b. RNA polymerase II
Which of the following is a pre-requisite for rRNA?
a. RNA polymerase I
b. RNA polymerase II
c. RNA polymerase III
a. RNA polymerase I
Which of the following is a pre-requisite for tRNA?
a. RNA polymerase I
b. RNA polymerase II
c. RNA polymerase III
c. RNA polymerase III
Which of the following promoters is farthest away from the start of transcription?
a. Hogness box
b. CAAT box
c. TATA box
b. CAAT box
Hogness box= TATA box
Which of the following unwinds the local DNA?
a. RNA polymerase I
b. RNA polymerase II
c. RNA polymerase III
b. RNA polymerase II
What does the death cap mushroom do?
a. inhibits mRNA synthesis by binding to RNA poly II
b. causes ROS build up by inhibiting mitochondrial activity
c. adds acetyl group to chromatin to unwind and tangle all DNA
a. inhibits mRNA synthesis by binding to RNA poly II
mRNA does through co- and post-transcriptional modifications. Which of the following is a post-transcriptional modification?
a. 5’ capping
b. 3’ poly-A tail
b. 3’ poly-A tail
a= co-transcription because the mRNA needs to be protected and stabilized right away
Which of the following needed an ATP substrate to install?
a. 5’ capping
b. 3’ poly-A tail
b. 3’ poly-A tail
In what direction os the 5’ cap added?
a. 3’->5’
b. 5’->3’
c. 5’->5’
c. 5’->5’
triphosphate linkage
Which of the following aid in intron splicing?
a. snRNA
b. snRNPs
c. snoRNA
d. miRNA
b. snRNPs
Which RNA splicing mutation type originated because of a homozygous mutation?
a. β0 thalassemia
b. β+ thalassemia
a. β0 thalassemia
Which RNA splicing mutation type originated because of a point mutation?
a. β0 thalassemia
b. β+ thalassemia
b. β+ thalassemia
Which of the following mice is more likely to get diseases?
a. their mom is given a normal diet and supplements
b. the agouti gene is hypomethylated
c. the agouti gene is hypermethylated
b. the agouti gene is hypomethylated
Which of the following bee is more likely to become a worker bee?
a. DNA methyltransferase gene is hypomethylated
b. DNA methyltransferase gene is hypermethylated
c. one given royal honey
a. DNA methyltransferase gene is hypomethylated
Where does methylation most commonly occur?
a. third carbon of CpG’s Guanine
b. fifth carbon of CpG’s Cytosine
c. third carbon of ApT’s Adenine
d. fifth carbon of ApT’s Thymine
b. fifth carbon of CpG’s Cytosine
Which of the following induces gene expression?
a. acetylation of histones
b. deacetylation of histones
a. acetylation of histones
Which of the following is true?
a. housekeeping genes are expressed under certain conditions
b. cis-acting DNA elements attach to trans-acting molecules to activate or suppress genes
c. trans-acting molecules bind to cis-acting DNA elements to activate or suppress genes
d. trans-acting molecules are synthesized from the targeted gene
c. trans-acting molecules bind to cis-acting DNA elements to activate or suppress genes
What is FALSE about glucocorticoid receptor?
a. inactivated form found in the cytosol
b. responds to hormones
c. the steroid receptor complex needs a coactivator to regulate genes
d. they’re all true
d. they’re all true
Which of the following is where the peptide bonds of proteins are formed?
a. A-site
b. P-site
c. E-site
a. A-site
Which of the following is where free tRNA exits?
a. A-site
b. P-site
c. E-site
c. E-site
Which of the following is where protein initiation begins?
a. A-site
b. P-site
c. E-site
b. P-site
What is the function of the anticodon arm of tRNA?
a. accepts new amino acids
b. read genetic codes
b. read genetic codes
Which of the following delivered the third amino acid in a protein?
a. elongator tRNA
b. initiator tRNA
a. elongator tRNA
only the first AA is delivered by initiator tRNA
What is the function of aa tRNA synthetase?
a. activate tRNAs into aa tRNA
b. helps free tRNA exit the ribosome
c. proof-read
d. A&B
e. B&C
e. A&C
e. A&C
Which of the following accurately describes the double-sieve proofreading mechanism?
a. proofreading site receives correct AA then it participates in translation
b. the hydrolytic site receives correct AA then it participates in translation
c. the hydrophobic site receives correct AA then it participates in translation
d. the hydrophilic site receives correct AA then it participates in translation
c. the hydrophobic site receives correct AA then it participates in translation
Which of the following amino acids is the first on in prokaryotes?
a. Methioine
b. fMethionine
b. fMeth
a= initiator aa of eukaryotes
Which of the following is the initiator codon?
a. AUG
b. UGA
c. UAG
d. UAA
a. AUG
the rest are stop codons
Which of these factors inhibits 50s binding (in the 30S complex)?
a. IF1
b. IF2
c. IF3
c. IF3
Which of these factors blocks the A-site of the 30S complex?
a. IF1
b. IF2
c. IF3
a. IF1
Which of these factors place initiator tRNA at the P-site (in the 30S complex)?
a. IF1
b. IF2
c. IF3
b. IF2
Which of these factors does NOT participate in joining the 50s subunit to the 30s complex?
a. IF1
b. IF2
c. IF3
c. IF3
In which of the following does the first codon (AUG) lie in the Kozak sequence?
a. prokaryotic cells
b. eukaryotic cells
b. eukaryotic cells
Which elongation factor of prokaryotes stabilizes the aa tRNA and helps it get to the A-site?
a. Ts
b. Tu
b. Tu
Which of the following proteins start synthesis in the ribosome?
a. catagory 1
b. catagory 2
c. category 3
d. all of the above
d. all of the above
Which of the following proteins end the synthesis in the ribosome?
a. catagory 1
b. catagory 2
c. category 3
d. A&B
e. A&C
f. all of the above
e. A&C
Which of the following proteins has a targeting sequence at the N-terminus that gets cleaved after it reaches its destination?
a. nuclear proteins
b. mitochondrial proteins
c. cytosol proteins
d. peroxisomal proteins
b. mitochondrial proteins