Quiz Flashcards
Integrins are
A) transmembrane proteins
B) peripheral membrane proteins
C) components of the extracellular matrix
D) components of a desmosome
A)
Cell adhesion molecules can be divided into four major groups. Which is not one of those groups?
A) selectins
B) integrins
C) collagens
D) immunoglobulin superfamily
C)
True or false: tight junctions provide strong adhesions between cells.
False
In E. coli, the major enzyme responsible for DNA replication is DNA polymerase
A) I
B) II
C) III
D) sigma
C)
Which eukaryotic DNA polymerase replicates the lagging strand in the 3’ to 5’ direction?
A) alpha
B) gamma
C) sigma
D) none of the above; the lagging strand is replicated in the 5’ to 3’ direction
D)
Telomerase is
A) a reverse transcriptase
B) the enzyme that adds a random sequence to the ends of chromosomes
C) an enzyme first discovered in thermus aquaticus
D) an enzyme that breaks down DNA from the ends
A)
True or false: the leading and lagging strands at a replication fork are synthesized in opposite directions, but both are synthesized in a continuous manner.
False
The DNA sequence to which an RNA polymerase binds to initiate transcription of a gene is called a(n)
A) enhancer
B) promoter
C) polymerase-binding element
D) origin of transcription
promoter
RNA polymerase differs from DNA polymerase in that it
A) synthesizes new strands of RNA in a 3’ to 5’ direction
B) is a monomeric protein
C) can synthesize a complementary strand without the two strands of DNA being separated
D) does not require a primer to initiate synthesis of RNA
D)
The TATA box is similar to the ______ in E. coli.
A) -35 promoter sequence
B) -10 promoter sequence
C) +1 transcription start site
D) None of the above
B)
A major difference between eukaryotic and prokaryotic RNA polymerases is that eukaryotic polymerases
A) use a set of transcription factors to bind to and initiate transcription
B) use sigma (s) factors to initiate transcription
C) start from promoters
D) start from origins of replication
A
True or false: the s subunit of E. coli RNA polymerase is necessary for transcriptional elongation.
False
In the presence of both glucose and lactose, the lac operon will
A) be active because the negative regulation by the lac repressor will be removed
B) not be active because of negative regulation by the lac repressor
C) be active because of the lack of positive regulation by cAMP-CAP
D) be active because of positive regulation by cAMP-CAP
C)
An operon is
A) an individual gene under the control of multiple promoters
B) multiple genes under the control of a single promoter, producing multiple mRNAs
C) multiple promoters controlling multiple genes simultaneously
D) multiple genes under the control of a single promoter, producing a single mRNA with multiple coding regions
D)
True or false: some corepressors bind to transcription factors at transcription initiation sites and recruit deacetylases that remove acetyl groups from histone lysine groups, leading to condensation of chromatin and repression of transcription.
True
The first amino acid that initiates the eukaryotic polypeptide is
A) any amino acid
B) glutamine
C) methionine
D) N-formylmethionine
C)
(N-formylmethionine starts polypeptides in bacteria and organelles)
In translation, mRNAs are read in the ______ direction, and polypeptide chains are synthesized from the ______ ends.
A) 5’ to 3’; carboxyl to the amino
B) 5’ to 3’; amino to the carboxyl
C) 3’ to 5’; carboxyl to the amino
D) 3’ to 5’; amino to the carboxyl
B)
Which amino acid is not commonly phosphorylated to regulate protein activity?
A) serine
B) threonine
C) tryptophan
D) tyrosine
C)
The capacity for some tRNAs to recognize more than one codon in mRNA is explained by a phenomenon called
A) redundancy
B) wobble
C) reading frameshift
D) degeneracy
B)
True or false: cells contain 64 tRNAs, with one anticodon for each codon.
False
True or false: transmembrane proteins in the plasma membrane are synthesized on the rough ER
True
Which coat protein directs retrograde vesicular transport from the ERGIC or Golgi to the ER?
A) COP II
B) COP I
C) clathrin
D) both COP II and COP I
B)
Using radiolabeled amino acids, Palade and colleagues defined the pathway taken by secreted proteins. Which sequence represents that pathway?
A) Rough ER; smooth ER; Golgi; secretory vesicles; cell exterior
B) Rough ER; smooth ER; Golgi; endosomes; cell exterior
C) Rough ER; Golgi; lysosomes; cell exterior
D) Rough ER; Golgi; secretory vesicles; cell exterior
D)
True or false: the main method by which a cell gets rid of old, worn-out organelles is exocytosis.
False
True or false: the initial site of N-linked glycosylation is the Golgi apparatus.
False
