2017 biochem midterm Flashcards
Which polymerase possesses 5’ —— 3’ exonuclease activity in prokaryotes?
a. DNA polymerase 3
b. DNA polymerase 2
c. DNA polymerase 4
d. DNA polymerase 1
d. DNA polymerase 1
If you choose annealing temperature higher than the melting temperature of your primer. What will happen to the PCR reaction?
a. Taq polymerase denaturation
b. Failure of DNA separation
c. Failure of primer binding
d. Formation of primer dimer
c. Failure of primer binding
What serves as an allosteric inhibitor of pyruvatic dehydrogenase-kinase?
a. Acetyle coA
b. Mg+2
c. NAD+
d. NADH
c. NAD+
During which PCR step does DNA synthesis occur?
a. Annealing
b. Denaturation
c. Extension
d. Storage
c. Extension
What is the primary function of NADPH / NADP?
a. Anabolic
b. Catabolic
c. Oxidation
d. Phosphorylation
a. Anabolic
What is the most common deleted amino acid in cystic fibrosis?
a. GLY 509
b. ISO 506
c. ISO 507
d. PHE 508
d. PHE 508
Which translation step will be inhibited if an antibiotic binds to the A site of the ribosome?
a. Initiation
b. Elongation
c. Termination
d. Charging of tRNA
b. Elongation
Which force stabilizes a secondary structure of a protein?
a. H bonds
b. Hydrophobic interactions
c. Peptide bonds
d. S-S bonds
a. H bonds
Which epigenetic change is likely to inhibit gene expression?
a. Cytosine
b. Guanosine
c. Adenine
a. Cytosine
Restriction endonucleases work on what?
a. Single stranded RNA
b. Single stranded DNA
c. Double stranded RNA
d. Double stranded DNA
d. Double stranded DNA
Which test is used to diagnose patients with cystic fibrosis?
a. Free ion test
b. Pulmonary function test
c. Blood lipase test
d. Sweat test
d. Sweat test
Which percentage of the genome do repetitive elements contribute to?
a. 60%
b. 47%
c. 23%
d. 10%
b. 47%
Which of the following allows reaction catalyzed by glyceraldehyde -3- phosphate dehydrogenase when glucose is metabolized anaerobicly?
a. NADH oxidation by lactate dehydrogenase
b. Reduction of NAD+ to NADH in mitochondria
a. NADH oxidation by lactate dehydrogenase
What is the function of tge Srn protein?
a. Cytosol phosphorylation
b. Nucleus transcription actor
c. Membranous receptor
a. Cytosol phosphorylation
Which type of point mutation is involved in converting purine to pyrimidine?
a. Transposition
b. Transition
c. Deletion
d. Transversion
d. Transversion
What are transcription factors?
a. Catalytic molecules
b. Cis acting proteins
c. DNA segments
d. Regulating proteins
d. Regulating proteins
On which site does aa- tRNA binds in elongation?
a. A site
b. P site
c. E site
a. A site
What is the natural function of restricting enzymes?
a. Protecting bacteria by cleaving the DNA of infecting viruses
b. Protecting bacteria by degrading the RNA of infecting viruses
c. Protecting bacteria by methylating their RNA
d. Protecting bacteria by methylating the DNA of infecting viruses
a. Protecting bacteria by cleaving the DNA of infecting viruses
At which level is apo B regulated?
a. MRNA editing
b. MRNA splicing
c. Formation of poly A tail
a. MRNA editing
Which of the following use glucagon stores to increase blood glucose?
a. Skeletal muscles
b. Liver
c. Kidney
d. Adipose
b. Liver
Which of the following is the main product of non-oxidized pentose phosphate pathway?
a. Ribose -5- phosphate
b. Glucose -6- phosphate
c. Conversion of AMP and ADP to ATP
d. Reducing NAD+ to NADH
a. Ribose -5- phosphate
Which of the following causes the base selective termination?
a. DDNTP
b. DNTP
a. DDNTP
Which pairs are products of catabolic pathway?
a. ATP , NADH
b. ATP , NAD+
c. ADP , NADH
d. ADP , NAD+
a. ATP , NADH
What is the main step that regulates a metabolic pathway?
a. First reaction that leads only to the product
b. Last reaction in the pathway
c. Fastest reaction in the pathway
d. If delta G = 0
a. First reaction that leads only to the product
To which human genome do Alu elements belong?
a. Long terminate repeat sequence
b. Long interspersed sequence
c. Short interspersed sequence
d. Tandem repeat sequence
c. Short interspersed sequence
In PCR experiment we use only single strand DNA, what would be the product number If we do 20 cycles?
a. 20
b. 40
c. 60
a. 20
What characterizes a prion?
a. Change in alpha helices
b. Change in beta sheets
c. Change in primary protein structure
b. Change in beta sheets
What is the theory behind Alzheimer’s disease?
a. Protein synthesis
b. Protein processing
c. Protein infolding
d. Protein secretion
b. Protein processing
What is the characteristic of isozymes?
a. Same product and substrate
b. Same sub-cellular locations
c. Same coenzyme
a. Same product and substrate
What activates zymogen into an active enzyme?
a. Proteolysis
b. Oxidation
c. Phosphorylation
a. Proteolysis
Why is the template DNA invisible in agarose gel?
a. DNA template resolves into the gel
b. DNA template hydrolyzed
c. Amount of template isn’t enough
c. Amount of template isn’t enough
What does camptothecin inhibit?
a. DNAa
b. Topoisomerase 1
c. Topoisomerase 2
b. Topoisomerase 1
What is the most abundant in RNA?
a. rRNA
b. tRNA
c. mRNA
a. rRNA
Which of the following is involved in rRNA processing?
a. SnRNA
b. SnoRNA
c. TRNA
b. SnoRNA
Energy released from reduction of O2 to water is used in?
a. Pumping H+
b. Substrate – level phosphorylation
a. Pumping H+
What stimulates gluconeogenesis?
a. high activity of fructose 2,6 bisphosphate
b. low activity of fructose 2,6 bisphosphate
c. epinephrine
low activity of fructose 2,6 bisphosphate
What does the acetylation of Arg in histone do?
a. surpasses negative charge of histone tail
b. surpasses positive charge of histone tail
c. strengthen histone to DNA binding
b. surpasses positive charge of histone tail
What causes the activation of RAS proto-oncogene?
a. Translocation
b. Point mutation
c. Gene deletion
b. Point mutation
How does glycosyl transferase sense that a protein is unfolded?
a. Presence of alpha-helical structure
b. Presence of beta structure
c. Presence of exposed hydrophobic aa
d. Presence of peptide bond
c. Presence of exposed hydrophobic aa
What is a general property of an allosteric site?
a. High affinity for substrate and product
b. Ligand binding influences protein conformation
c. High affinity for coenzyme
d. Formed by covalently attached prosthetic groups
b. Ligand binding influences protein conformation