Exam 2 Missed Questions Flashcards
Which DNA base pair is represented in the figure below?
A-T
T-A
G-C
C-G
T-A
If the genome of the bacterium E. coli requires about 20 minutes to replicate itself, how can the genome of the fruit fly Drosophila be replicated in only 3 minutes?
- The Drosophila genome is smaller than the E. coli genome
- Drosophila DNA contains more origins of replication than E. coli DNA
- Eukaryotic DNA polymerase synthesizes DNA at a much faster rate than prokaryotic DNA polymerase
- The nuclear membrane keeps the Drosophila DNA concerted in one place in the cell, which increases the rate of polymerization
Drosophila DNA contains more origins of replication than E. coli DNA
Sometimes, chemical damage to DNA can occur just before DNA replication begins, not giving the repair system enough time to correct the error before the DNA is duplicated. This gives rise to mutation. If the cytosine in the sequence TCAT is deaminated and not repaired, which of the following is the point mutation you would observe after this segment has undergone to rounds of DNA replication?
- TUAT
- TGAT
- TAAT
- TTAT
TTAT
Select the option that best completes the following statement: Nonhomologous end joining is a process by which a double stranded DNA end is joined
- to a similar stretch of sequence on the complementary chromosome
- after repairing any mismatches
- to the nearest available double-stranded DNA end
- after filling in any lost nucleotides, helping to maintain the integrity of the DNA sequence
to the nearest available double-stranded DNA end
Total nucleic acids are extracted from a culture of yeast cells and are then mixed with resin beads to which the polynucleotide 5’-TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT-3’ has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following is most abundant?
- DNA
- mRNA
- tRNA
- rRNA
mRNA
In eukaryotes, but not in prokaryotes, ribosomes find the start site of translation by
-binding directly to a ribosome-binding site preceding the initiation codon
-scanning along the mRNA from the 5’ end
-recognizing an AUG codon as the start of translation
biniding an initiator tRNA
scanning along the mRNA from the 5’ end
Ribozymes are known to catalyze which of the following reactions in cells?
- DNA synthesis
- transcription
- RNA splicing
- protein hydrolysis
RNA splicing
miRNAs, tRNAs, and rRNAs all
- do not code for proteins
- act in the nucleus
- are packaged with other proteins to form RISC
- form base pairs with mRNA molecules
do not code for proteins
Which of the following statements about transcriptional regulators is FALSE?
- Transcription regulators interact only with the sugar-phosphate backbone on the outside of the double helix to determine where to bind on the DNA helix
- Transcription regulators will form hydrogen bonds, ionic bonds, and hydrophobic interactions with DNA
- The DNA-binding motifs of transcription regulators usually bind in the major groove of the DNA helix
- The binding of transcription regulators generally does not disrupt the hydrogen bonds that hold the double helix together.
Transcription regulators interact only with the sugar-phosphate backbone on the outside of the double helix to determine where to bind on the DNA helix
Which of the following statements about DNA methylation in eukaryotes is FALSE?
- Appropriate inheritance of DNA methylation patterns involve maintenance methyltransferase
- DNA methylation involves a covalent modification of cytosine bases
- Methylation of DNA attracts proteins that block gene expression
- Immediately after DNA replication, each daughter helix contains one methylated DNA strand which corresponds to the newly synthesized strand.
Immediately after DNA replication, each daughter helix contains one methylated DNA strand which corresponds to the newly synthesized strand.
