Chapter 13 and 14
RNA polymerase moves in which direction along the DNA?
3' to 5' along the template strand
An Okazaki fragment has which of the following arrangements? 5' DNA to 3' 5' RNA nucleotides, DNA nucleotides 3' 3' RNA nucleotides, DNA nucleotides 5' DNA polymerase I, DNA polymerase III primase, polymerase, ligase
5' RNA nucleotides, DNA nucleotides 3'
A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which of the following might this illustrate? The sequence evolves very rapidly. The sequence is found in many but not all promoters. The sequence does not mutate. The sequence is transcribed at the start of every gene. Any mutation in the sequence is selected against.
Any mutation in the sequence is selected against.
Suppose you are provided with an actively dividing culture of Escherichia coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
A new DNA strand elongates only in the 5' to 3' direction because
DNA polymerase can only add nucleotides to the free 3' end.
In the process of DNA replication, two DNA double helices are formed from one parental DNA double helix. What is the distribution of parental DNA strands in the newly formed DNA double helices?
Each resulting DNA double helix contains exactly 1 parental strand
DNA polymerases have slower rates of catalysis and are less error-prone than RNA polymerases.
False
Prokaryotic genomes typically consist of single-stranded DNA, whereas eukaryotic genomes contain double-stranded DNA.
False
DNA helicase breaks which type of bond in the DNA molecule?
Hydrogen bonds
Which of the following is a function of a poly-A tail in mRNA? It adds the modified guanine to the 3' end of the mRNA. It helps protect the mRNA from degradation by hydrolytic enzymes. It indicates the site of translational termination. It is a sequence that codes for the binding of RNA polymerase to the DNA.
It helps protect the mRNA from degradation by hydrolytic enzymes.
Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes? Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. Prokaryotes have telomeres, and eukaryotes do not. The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes. Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
Both synthesize nucleic acids from a DNA template.
True
Both synthesize nucleic acids in the 5´→3´ direction.
True
DNA polymerases require a primer, whereas RNA polymerases do not.
True
Most DNA polymerases have a 3´→5´ proofreading exonuclease activity, whereas RNA polymerases do not.
True
Prokaryotic chromosomes are typically circular, whereas eukaryotic chromosomes are linear.
True
Prokaryotic genomes are compacted into a structure called the nucleoid, whereas eukaryotic genomes are segregated within the nucleus of the cell.
True
Prokaryotic genomes are monoploid, whereas eukaryotic genomes are diploid.
True
Prokaryotic genomes typically consist of one chromosome, whereas eukaryotic genomes have multiple chromosomes.
True
What is the main function of DNA helicase in DNA replication?
Unzipping the DNA double helix
What does "transfer RNA" actually transfer?
amino acids
Why does a DNA strand grow only in the 5ʹ to 3ʹ direction?
because DNA polymerases can only add nucleotides to the 3' end of the growing molecule
Where do transcription and translation occur in prokaryotic cells?
cytoplasm
We would expect that a 15-nucleotide sequence that includes a stop codon at the end (as part of the 15-nucleotide sequence) will direct the production of a polypeptide that consists of
four amino acids.
Which of the following occurs when RNA polymerase attaches to the promoter DNA? initiation of a new polypeptide chain initiation of a new RNA molecule elongation of the growing RNA molecule termination of the RNA molecule
initiation of a new RNA molecule
Consider the DNA sequence below, which is being replicated from left to right. 5´-GTTAAACTTCGGATCGGCTCTGTCGCTT-3´ 3´-CAATTTGAAGCCTAGCCGAGACAGCGAA-5´ The top strand will be the template for the _____ strand, which is replicated _______. The bottom strand will be the template for the ______ strand, which is replicated _________ .
lagging; discontinuously leading; continuously
Small pieces of RNA that can regulate translation of mRNA are called
microRNA.
RNA splicing involves the
removal of introns from the molecule.
Transcription in eukaryotes requires which of the following in addition to RNA polymerase?
several transcription factors
Suppose that the human insulin protein that was produced by the bacteria was much shorter than it should be. Upon further investigation, it was found that the DNA of the human insulin gene had a mutation while in the bacterial cells. What type of mutation could not result in these observations?
silent mutation
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that many codons are never used, so the tRNAs that recognize them are dispensable. some tRNAs have anticodons that recognize four or more different codons. the rules for base pairing between the third base of a codon and tRNA are flexible. the DNA codes for all 61 tRNAs, but some are then destroyed. competitive exclusion forces some tRNAs to be destroyed by nucleases.
the rules for base pairing between the third base of a codon and tRNA are flexible.
What is the function of DNA polymerase III?
to add nucleotides to the 3' end of a growing DNA strand