biology chapter 17
If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein?
2
A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is
3' UCA 5'.
You were exposed to 4 millisieverts of radiation last year. That is ______ times the maximum recommended by the International Commission on Radiological Protection.
4
Life as we know it depends on the genetic code: a set of codons, each made up of three bases in a DNA sequence and corresponding mRNA sequence, that specifies which of the 20 amino acids will be added to the protein during translation. Imagine that a prokaryote-like organism has been discovered in the polar ice on Mars. Interestingly, these Martian organisms use the same DNA → RNA → protein system as life on Earth, except that there are only 2 bases (A and T) in the Martian DNA, and there are only 17 amino acids found in Martian proteins. Based on this information, what is the minimum size of a codon for these hypothetical Martian life-forms?
5 bases
The direction of synthesis of an RNA transcript is _____.
5'-->3'
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A gene from an organism can theoretically be expressed by any other organism
Transcription begins at a promoter. What is a promoter?
A site in DNA that recruits the RNA Polymerase
At which site do new aminoacyl tRNAs enter the ribosome during elongation?
A-site
The nitrogenous base adenine is found in all members of which group?
ATP, RNA, and DNA
If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred?
An addition mutation and a deletion mutation
What determines which base is to be added to an RNA strand during transcription?
Base pairing between the DNA template strand and the RNA nucleotides
The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____.
CUG
What radioactive element is being tested for in this ongoing project?
Cesium
where does the translation of secreted proteins occur
ER
Rheumatoid arthritis, celiac disease, and multiple sclerosis are all autoimmune diseases. Which of the following is true?
Gene switches likely play a role in these diseases.
Garrod's information about the enzyme alteration resulting in alkaptonuria led to further elucidation of the same pathway in humans. Phenylketonuria (PKU) occurs when another enzyme in the pathway is altered or missing, resulting in a failure of phenylalanine (phe) to be metabolized to another amino acid: tyrosine. Tyrosine is an earlier substrate in the pathway altered in alkaptonuria. How might PKU affect the presence or absence of alkaptonuria?
It would have no effect, because tyrosine is also available from the diet.
The average length of a transcription unit along a eukaryotic DNA molecule is about 27,000 nucleotide pairs, whereas an averaged-sized protein is about 400 amino acids long. What is the best explanation for this fact?
Most eukaryotic genes and their RNA transcripts have long noncoding stretches of nucleotides that are not translated
The initiator tRNA attaches at the ribosome's _____ site.
P
Members of what organization collected samples that have indicated high radiation levels in Tokyo?
Radiation Defense Project
Where does translation take place
Ribosome
According to the findings in this study, which of the following is true?
The environment plays a role in the cause of certain diseases
Which of the following statements best describes the promoter of a protein-coding gene?
The promoter is a nontranscribed region of a gene
What is meant by translocation
The ribosomal subunits are joined in a complex
During RNA processing a(n) _____ is added to the 3' end of the RNA.
a long string of adenine nucleotides
What caused the nuclear accident at Fukushima?
a tsunami
Polypeptides are assembled from _____.
amino acids
What enzyme catalyzes the attachment of an amino acid to tRNA?
aminoacyl-tRNA synthesae
Amino acids are attached to tRNA by enzymes called
aminoacyl-tRNA synthetase
A simple metabolic pathway is shown below. A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?
an accumulation of A and no production of B and C
Generally speaking, which of the following mutations would most severely affect the protein coded for by a gene? a) a base substitution at the beginning of the gene b) a base substitution at the end of the gene c) a frameshift deletion at the beginning of the gene d) a frameshift deletion at the end of the gene
c
Which of the following mutations would likely be most dangerous to a cell? a) Deletion of three nucleotides b) Substitution of one nucleotide for another c) Deletion of one nucleotide
c
Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?
complementary
Translation occurs in the ___
cytoplasm
where does the attachment of amino acids to tRNA occur
cytoplasm
Gene switches likely play a role in these diseases.
dark matter
If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred?
deletion
The function of tRNA during protein synthesis is to ___
deliver amino acids to their proper site during protein synthesis
The RNA segments joined to one another by spliceosomes are _____.
exons
True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated.
false
True or false? A codon is a group of three bases that can specify more than one amino acid.
false
Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because
genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.
___ of translation always happens when the ribosome hits a stop codon on the mRNA
intiation
What happens to RNA polymerase II after it has completed transcription of a gene?
it is free to bind to another promoter and begin transcription
RNA processing converts the RNA transcript into _____.
mRNA
Which nucleic acid is translated to make a protein
mRNA
contains exons specifies the amino acid sequence for a protein
mRNA
A virus infects a cell and randomly inserts many short segments of DNA containing a stop codon throughout an organism's chromosomes. This will probably cause ___
manufactured proteins to be short and defective
If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be capable of growing on which of the following media?
minimal medium supplemented with C only
If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?
minimal medium supplemented with nutrient B only
During RNA processing a(n) _____ is added to the 5' end of the RNA.
modified guanine nucleotide
Where does transcription and RNA processing occur
nucleus
where does the formation of ribosomal subunits occur
nucleus
Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)?
one addition and one deletion mutation
DNA does not store the information to synthesize which of the following?
organelles
Which of the following processes is an example of a post-translational modification?
phosphorylation
is a component of ribosomes is the most abundant form of RNA
rRNA
Where does the translation of cytoplasmic proteins occur
ribosomes
Spliceosomes are composed of _____.
snRNPs and other proteins
The RNA that has an amino acid attached to it, and that binds to the codon on the mRNA, is called
tRNA
contains an anitcodon has amino acids covalently attached
tRNA
___ of translation happens when the ribosome hits a stop codon on the mRNA
termination
During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3'→5' direction. However, for any given gene, either strand of the double-stranded DNA may function as the template strand. For any given gene, what ultimately determines which DNA strand serves as the template strand?
the base sequence of the gene's promoter
Which of the following steps occurs last in the initiation phase of translation?
the large ribosomal subunit joins the complex
What is the process called that converts the genetic information stored in DNA to an RNA copy?
transcription
The process,, performed by the ribosome, of reading mRNA and synthesizing a protein is called
translation