2010 biochem midterm Flashcards
What is the last step of DNA replication?
a. filling in RNA primase gaps with DNA
b. ligation of Okazaki fragments
c. relaxing the supercoiled DNA
b. ligation of Okazaki fragments
How can you indicate intron?
a. 5’ CA - AT 3’
b. 5 CA - AT 3
c. 5 GU - AG 3
d. 5’ GU - AG 3’
d. 5’ GU - AG 3’
Which RNA is synthesized by RNA polymerase III?
a. mRNA
b. tRNA
c. rRNA
b. tRNA
What best characterizes euchromatin?
a. actively transcripted
b. most inactive DNA segment
c. condensed chromatin
a. actively transcripted
Which system is the most affected by cystic fibrosis? A. Respiratory system B. Nervous system C. Musculoskeletal system D. Circulatory system
A. Respiratory system
Why does ddNTP stop DNA synthesis?
a. it’s tagged
b. it doesn’t provide 3OH
c. it blocks mRNA
d. it blocks tRNA
b. it doesn’t provide 3OH
What causes mad cow disease (prion disease)?
a. Incorrect protein folding
b. point mutation
c. protein degradation error
a. Incorrect protein folding
Which mechanism is used to repair xeroderma pigmentosum?
a. Base excision repair
b. Mismatch repair system
c. Nucleotide excision repair
c. Nucleotide excision repair
What is the activated form of glucose that synthesizes glycogen? A. UDP-glucose B. G-6-P C. G-1-P D. UTD-glucose
A. UDP-glucose
What type of mutation occurs in phenylketonuria?
a. frameshift
b. silent
c. nonsense
d. missense
d. missense
What is the most common type of mutation affecting the fibrillin-1 gene?
a. nonsense
b. missense
c. frameshift
d. silent
b. missense
Which domain is affected by CFTR?
a. ATP domain
b. Ig-type domain
c. gene duplication domain
a. ATP domain
Laboratory assay had a sample with IU=2 and a protein of 10 mg, what is the specified activity?
a. 0.1
b. 0.2
c. 0.5
b. 0.2
IU/MASS = 2/10
In somatic cells of eukaryotes, what leads to shortening of the chromosome?
a. Low telomerase activity
b. High telomerase activity
c. Low RNase activity
d. High RNase activity
a. Low telomerase activity
What snrnp bind to 5’ end of intron?
a. U1
b. U2
c. U3
d. U4
a. U1
What is the function of restriction enzyme?
a. Cleavage of RNA at specific sites
b. Cleavage of DNA at specific sites
c. Reduce the bacterial grown to enhance the viral control
d. Protein degradation
b. Cleavage of DNA at specific sites
What groups of amino acids form peptide bonds in a protein?
a. side chain
b. α NH2 and α COO
c. hydrogen
b. α NH2 and α COO
What is proto-oncogenes?
a. genes that may be converted to oncogenes
b. cancerous genes
c. genes filled with mutations
a. genes that may be converted to oncogenes
normal genes which, when altered by mutation, become oncogenes that can contribute to cancer
Penicillin is a suicide inhibitor, why?
a. It inhibits cell suicide (apoptosis)
b. It interacts covalently with the enzyme
c. It phosphorylates the cell surface
b. It interacts covalently with the enzyme
Which of the following undergoes hydrolyxation?
a. Proteins
b. RNA
c. DNA
d. Collagen
d. Collagen
If we have 20 PCR cycle, how many initial folds would we have in DNA sequencing?
a. 4 folds
b. 10 folds
c. 20 folds
d. 35 folds
c. 20 folds
Which of the following is used in DNA fingerprinting?
a. Minisatellite
b. PCR
a. Minisatellite
What is the effect of vitamin C in synthesizing collagen?
Hydroxylation of proline
Which of the following will be inhibited if antibiotics stopped the formation of 30s complex?
a. elongation
b. initiation
c. folding
b. initiation
Which of the following binds to lysosomal protein?
a. G-1-P
b. M-3-P
c. M-6-P
d. G-6-P
c. M-6-P
Calcitonin expression is changed at which stage?
Polyadenylation and splicing
Which of the following is true concerning allosteric enzymes?
a. always increase enzymatic activity
b. always decrease enzymatic activity
c. bind outside the active site
c. bind outside the active site
What is the function of glycogenin in glycogen?
a. Act as a primer in glycogen formation
b. Secures the edges of glycogen are closed
a. Act as a primer in glycogen formation
Where unfolded proteins are degraded?
a. Cytosol
b. Golgi
c. ER
d. Lysosomes
c. ER
What is the difference in the initiation stage between eukaryotic & prokaryotic translation?
Searching for the start codon in the sequence
What is the mutation of collagen structure in osteogenesis that’s imperfect?
Covalent bond OR (disulfide bond)
What leads to the accumulation of hemoglobin in sickle cell disease?
Deoxygenation
What is a metaphasic chromosome? A. uncompacted DNA B. naked DNA molecule without histones C. single-stranded DNA D. double-stranded DNA molecule with histones E. 4 DNA stands with histones
E. 4 DNA stands with histones
As temperature increases, it has a negative effect on the activity of the enzyme, what is the best epanation for the decline?
A. Enzyme denaturation
B. ∆G ↓
C. Activation E ↓
A. Enzyme denaturation
What is the structure of metaphasic chromosome?
A. Naked DNA protein without histones
B. Double strand DNA molecule with histones
C. Four strands of DNA with histones
C. Four strands of DNA with histones
