Exam 3 review Flashcards
What was the conclusion of Avery’s experiment in 1944?
That DNAse destroyed the transforming principle.
In Griffith’s Transformation experiment in 1928 what became transformed?
R-Bacteria were transformed to S-bacteria
Transcription produces which of the following? A. BI-directional DNA B. Transfer RNA C. amino acids D. semi-conservative DNA E. Proteins
B. Transfer RNA
If DNA from a particular species contains 30% Adenine, how much Guanidine does it contain?
20%
Which of the following is TRUE in a DNA double helix? A. The two DNA strands are complementary B. Purines pair with Purines C. Thymine pairs with Cytosine D. The sugars in the backbone are ribose E. Two of these are true
A. The two DNA strands are complementary
The fact that replication forks each contain a leading strand and a lagging strand means that the DNA replication is: A. bi-directional B. asymmetrical C. processive D. semi-conservative E. error prone
B. asymmetrical
For the single strand of DNA 5’-CCGGTTAA-3’ what would be the opposite strand?
5’-GGCCAATT-3’
The region of DNA at which RNA polymerase binds to start transcription is the:
Promoter
Which of the following is NOT TRUE of RNA molecules?
A. the molecules are single-stranded
B. Nucleotides include adenine, guanine, cytosine, and uracil
C. the sugar found in the nucleotides is ribose
D. They are very stable and last a long time.
E. Actually all of these are
D. They are very stable and last a long time.
The genetic code is said to be ________ because more than one codon can specify an amino acid
degenerate
Which molecules code for proteins? A. tRNA B. mRNA C. rRNA D. all of these E. two of these
B. mRNA
Which tRNA binding site is the entry point for tRNA’s in the ribosome?
The A site
TRUE or FALSE The stop codons do not specify amino acids but the start codon does.
TRUE
Which of the following is true regarding bacterial transcription?
A. RNA polymerase binds to the promoter and waits for sigma factor to start transcribing.
B. Sigma factor binds to the promoter and waits for the polymerase to start transcribing
C. Sigma factor must be released to enter elongation.
D. RNA polymerase starts from a primer made by the primase
E. RNA polymerase binds to DNA only with the sigma factor.
C. Sigma factor must be released to enter elongation.
The main reason why DNA replication has to be asymmetrical is that
A. DNA polymerase proofreads
B. DNA polymerase is a 3’ to 5’ nucleotide polymerase
C. DNA polymerase requires a primer
D. DNA polymerase uses the 3’hydroxyl group from the nucleotide just added
E. two of these are correct.
D. DNA polymerase uses the 3’hydroxyl group from the nucleotide just added
During replication the 2 strands of the DNA molecule are unwound from one another by enzymes called A. ligases B. unwindases C. RNA polymerase D. helicases E. primases
D. helicases
The strand of the DNA double helix from which RNA polymerase reads is called the A. transcription strand B. sense strand C. translation strand D. template strand E. copy strand
D. template strand
TRUE or FALSE both the Lac and Trp operons are under negative control
TRUE
When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the A. operon B. operator C. promoter D. regulator E.activator
C. promoter
–Promoter-Operato–GeneA–GeneB–
Negative transcriptional control
An activator protein that cannot bind to the activator binding site if a particular substance is present in the bacterial cell
Negative transcriptional control, repressable gene
The presence of a particular substance in the bacterial cell causes an operon to be transcribed
Inducible gene
The tryptophan operon co-repressor is
Tryptophan
Thymine Dimers are fixed by: A. Base excision repair B. Nucleotide excision repair C. Mismatch repair D. Proofreading E. Actually, they aren't fixed
B. Nucleotide excision repair
Mutations allowing for substitution of one purine for another or one pyrimidine for another is called a: A. Transversion mutation B. Transition mutation C. Frameshift mutation D. Silent mutation E. Nonsense mutation
B. Transition mutation
What type of mutation converts a codon for one amino acid, to a stop codon?
Nonsense Mutation
Which type of mutation involves a single base substitution that changes a codon for one amino acid into a codon for another?
Missense mutation and point mutation
When bacterial genes are transferred to another bacterium by a virus, it is called
Transduction
Lysine auxotrophs:
A. Produce their own lysine, and can only grown on media without lysine
B. Produce their own lysine, and can only grow on media with Lysine added
C. Shut off the Lys operon instead of turning it on
D. Are unable to produce lysine, and can only grow on media without lysine
E. Are unable to produce lysine, and can only grow on media with lysine added.
E. Are unable to produce lysine, and can only grow on media with lysine added.
Complementary DNA (cDNA) molecules are produced using A. Restriction endonucleases B. RNA Polymerase C. DNA ligase D. Reverse transcriptase E. RNA Polymerase
D. Reverse transcriptase
A DNA molecule used to carry a foreign gene into a host organism is called a: A. Plasmid B. Vector C. Probe D. Blot E. Phage
B. Vector
Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?
A. The fragments with the highest percentage of G and C will migrate fastest
B. The fragments with the highest percentage of A and T will migrate fastest
C. The largest fragments will migrate fastest
D. The smallest fragments will migrate fastest.
E. Small and large fragments will migrate at equal rates.
D. The smallest fragments will migrate fastest.
The purpose of the Southern blotting technique is to:
Detect specific DNA fragments from a mixture of DNA molecules
In the polymerase chain reaction (PCR), each cycle increases the DNA copy number how?
Exponentially
