exam 4 homeworks
Which of the labeled Okazaki fragments would be the first two to be synthesized? (The leading strands are nor shown)
D and C
If the DNA of a mammalian promoter region experiences increased methylation on cytosine which of the following results is most likely to occur?
inactivation of the gene
Which molecules directly participate in the process of translation?
mRNA, tRNA, and rRNA
Which of the following statements correctly describes a nucleotide composition?
nitrogenous base, sugar, and phosphate group
DNA ligase
plays role in the elongation of the lagging strand during DNA replication, joining Okazaki fragments together
Topoisomerase
relieves the strain in the DNA ahead of the replication fork caused by the untwisting of the double helix
DNA polymerase I
removes nucleotides from the RNA primer that is used for initiation DNA synthesis
At which site of mRNA is the ribosome recruited to initiate the translation process?
start codon
A particular triplet of bases in the coding sequence of DNA is 5'-AAA-3'. The anticodon on the tRNA that binds the mRNA codon is:
3′-AAA-5′
During elongation, nucleotides are added in which direction?
5' to 3' direction
Referring to the figure below, what bases will be added as DNA replication proceeds on the bottom strand?
5′ A G A C G A C 3′
Use this model of a eukaryotic primary transcript to answer the following question. Assuming that: E = exon and I = intron. 5′- UTR E1 I1 E2 I2 E3 I3 E4 UTR -3′ If the primary transcript is processed and transported to the cytosol, which of the following molecules best represents the mRNA that will be produced?
5′- UTR E1 E2 E3 E4 UTR -3′
A sample of double-stranded DNA contains 42% cytosine. Approximately what percent of the nucleotides in this sample will be thymine?
8
Which of the following combinations of base pairs will be found in a molecule of DNA?
A + C = G + T
During the elongation phase of translation, which site in the ribosome represents the first location where a codon pairs with an anticodon?
A site
Which one is polymerized in 5′→3′ during DNA synthesis?
All of these
Which of the following is NOT included in the functions of the 5' cap and poly-A tail in mRNA?
Assistance in terminating the translation.
Which one is the correct statement about the central dogma of molecular genetics?
DNA is transcribed to RNA which is translated to proteins
Which of the following best explains why a neuron and a pancreatic cell isolated from the same individual contain different sets of proteins?
Each cell type contains different regulatory proteins and, therefore, they express different proteins.
Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?
Enhancers are located considerable distances from the promoter; proximal control elements are close to the promoter.
Which of the following mechanisms is commonly used to coordinate the expression of multiple, related genes in eukaryotic cells?
Groups of genes that are expressed together have specific combinations of control elements.
Which of the following processes is the best way to determine whether alternative splicing of a given gene occurs?
Isolate mRNA from the given gene and compare the sequences.
Which of the following processes correctly describes alternative RNA splicing?
It can allow the production of proteins of different sizes and functions from a single mRNA.
Which of the following statements accurately describes the structure of a eukaryotic chromosome?
It is a single linear molecule of double-stranded DNA plus proteins.
Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes?
It is the recognition site for the binding of a specific transcription factor.
Why is it important to identify the promoter region first before the transcription process can start?
It is where the RNA polymerase binds to so the reading of the bases can start
Which of the following statements is TRUE regarding Okazaki fragments?
They are synthesized by DNA polymerase on the lagging strand
Which of the following best describes the redundancy in the genetic code?
More than one codon can specify the addition of the same amino acid.
In analyzing the number of different bases in a DNA sample, all of the following are true regarding the base pairing rule. (select all that apply)
Purines are always equal in amount to pyrimidines, Adenine always pairs with Thymine, Cytosine always pairs with Guanine
Which process occurs as part of transcription?
RNA is synthesized
In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a protein?
RNA polymerase II
Which of the following is a reason that the low error rate of DNA replication is important to evolution?
Rare errors are the source of variation.
A cell is considered to be differentiated if it has which of the following characteristics?
The cell produces proteins specific to a particular cell type.
Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication?
The leading strand is synthesized continuously in the 5'→ 3' direction, while the lagging strand is synthesized discontinuously in the 5'→ 3' direction.
Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA in DNA replication?
The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
Which of the following statements about RNA processing is FALSE?
The spliceosomes remove the exon in pre-mRNA
Which of the following functions are characteristic of general transcription factors in eukaryotes?
They bind to other proteins or to the TATA box.
A single base substitution mutation is likely to have a less harmful effect when the base change results in which of the following?
a codon that specifies the same amino acid as the original codon
Translation termination occurs when a ribosome interacts with which of the following structures?
a stop codon
Considering that a new DNA strand can elongate only in the 5′ → 3′ direction. Use the figure below to match the question to its answer. Which of the four segments of new DNA (lighter blue) could be leading strands? Which of the segments of new DNA (lighter blue) would be lagging strands, synthesized as a series of smaller Okazaki fragments?
a) B and C b) A and D
DNA polymerase III
adds nucleotides to the 3' end of a growing DNA strand
Which of the following results is most likely to occur if acetylation of histone tails in the chromatin of embryonic cells is increased?
decreased chromatin condensation
DNA methylation and histone acetylation are examples of which process?
epigenetic phenomena
Muscle cells differ from nerve cells mainly because they
express different genes
A section of DNA has the base sequence shown in #1. A mutation in this DNA strand results in the base sequence shown in #2. What type of mutation does this change represent? #1 5' - AGCGTTACCGT-3' #2 5'-AGGCGTTACCGT-3'
frameshift mutation
Single-strand DNA binding protein
helps to hold the DNA strands apart while they are being replicated
Which of the following statements correctly describes pyrimidines? (select all that apply)
includes cytosine and thymine, nitrogenous base composed of a single organic ring
Which of the following statements correctly describes purines? (select all that apply)
includes guanine and adenine, nitrogenous bases with two organic rings
Which of the following molecular structures contains codons?
mRNA
Which answer correctly compares the primary transcript in the nucleus of a eukaryotic cell with the functional mRNA?
the primary transcript is larger than the mRNA
In eukaryotes, which of the following is the first step in translation?
the small subunit of the ribosome recognizes and attaches to the 5′ cap of mRNA
In the structure of many eukaryotic genes, individual exons parallel which of the following?
the various domains of the protein product
Transcription in eukaryotes requires which molecules in addition to RNA polymerase?
transcription factors
The functioning of enhancers is an example of:
transcriptional control of gene expression
Helicase
unwinds the DNA double helix at the replication fork