Question 1

Why is the attachment of an amino acid to the correct tRNA considered to be such an important step in protein synthesis?

Accepted Answer

The results of experiments have shown that the anticodon of a tRNA charged with an incorrect amino acid still interacts with the complementary codon in mRNA,thus causing the wrong amino acid to be incorporated into the growing polypeptide chain.No proofreading or editing mechanism exists in the ribosome to remove these incorrect amino acids.

Question 2

DNA probes are often synthesized based on knowledge of the protein produced by a gene.What might be a potential problem of synthesizing DNA probes in this manner?

Accepted Answer

A) The deduced DNA probe would be missing introns associated with prokaryotic genes. 
B) Because codons in DNA are redundant,knowing which codon to assign an amino acid may be difficult. 
C) The deduced DNA probe would be missing introns associated with eukaryotic genes. 
D) Because codons in DNA are redundant,knowing which codon to assign an amino acid may be difficult,as well as the deduced DNA probe would be missing introns associated with eukaryotic genes. 
E) None of the answer options are correct. 
A) The deduced DNA probe would be missing introns associated with prokaryotic genes. 
B) Because codons in DNA are redundant,knowing which codon to assign an amino acid may be difficult. 
C) The deduced DNA probe would be missing introns associated with eukaryotic genes. 
D) Because codons in DNA are redundant,knowing which codon to assign an amino acid may be difficult,as well as the deduced DNA probe would be missing introns associated with eukaryotic genes. 
E) None of the answer options are correct. D

Question 3

Describe how it was determined that the genetic code was not overlapping.What evidence was used to support this?

Accepted Answer

Analyses of mutant RNAs showed that a single nucleotide change affects only one amino acid in the encoded protein.This was predictive of a nonoverlapping code.An overlapping code would predict that a single base change would alter as many as three amino acids at adjacent positions in the protein.

Question 4

What is post-translational processing? Why is it important for protein function?

Accepted Answer

Some proteins cannot function until they

Question 5

The ribosome is the primary site of:

Accepted Answer

A) oxidative phosphorylation. 
B) protein packaging. 
C) protein synthesis. 
D) cellular respiration. 
E) amino acid storage. 
A) oxidative phosphorylation. 
B) protein packaging. 
C) protein synthesis. 
D) cellular respiration. 
E) amino acid storage.

Question 6

How does a nonsense suppressor mutation prevent amber mutants from terminating their polypeptides prematurely?

Accepted Answer

A) The mutation turns the amber codon back into a wild-type codon. 
B) The mutation alters a tRNA so that it reads the amber codon and inserts an amino acid. 
C) The mutation alters the release factors that would halt synthesis. 
D) The mutation results in a wobble that allows synthesis to continue. 
E) The mutation replaces the amber codon with an ochre codon. 
A) The mutation turns the amber codon back into a wild-type codon. 
B) The mutation alters a tRNA so that it reads the amber codon and inserts an amino acid. 
C) The mutation alters the release factors that would halt synthesis. 
D) The mutation results in a wobble that allows synthesis to continue. 
E) The mutation replaces the amber codon with an ochre codon.

Question 7

The proteome for humans is about 70,000 proteins whereas only 21,000 protein-coding genes have been discovered.Which statement could explain this?

Accepted Answer

A) Splicing of eukaryotic mRNA can result in the production of more than one protein from a single gene. 
B) Many of our proteins are actually produced by symbiotic organisms in our bodies. 
C) Splicing of eukaryotic mRNA can result in the production of more than one protein from a single gene and many of our proteins are actually produced by symbiotic organisms in our bodies. 
D) We do not know enough about the human genome to explain this fact. 
A) Splicing of eukaryotic mRNA can result in the production of more than one protein from a single gene. 
B) Many of our proteins are actually produced by symbiotic organisms in our bodies. 
C) Splicing of eukaryotic mRNA can result in the production of more than one protein from a single gene and many of our proteins are actually produced by symbiotic organisms in our bodies. 
D) We do not know enough about the human genome to explain this fact.

Question 8

Francis Crick proposed "adapter" molecules to serve as an intermediary between mRNA and the synthesis of protein.Key to any model of how RNA is "read" in the process of protein synthesis would be a consideration of how:

Accepted Answer

A) amino acids are selected for addition to the new protein. 
B) the RNA code was read by the translation enzyme. 
C) peptide bonds are formed. 
D) one codon could select a specific amino acid. 
E) All of the answer options are correct. 
A) amino acids are selected for addition to the new protein. 
B) the RNA code was read by the translation enzyme. 
C) peptide bonds are formed. 
D) one codon could select a specific amino acid. 
E) All of the answer options are correct.

Question 9

Two gametes,each carrying a mutant recessive allele for a different gene/enzyme in the adenine biosynthetic pathway,come together to form a diploid embryo.The individual derived from this embryo will display a:

Accepted Answer

A) lethal phenotype in media lacking adenine supplementation. 
B) wild-type phenotype,capable of synthesizing adenine. 
C) a weak adenine requirement for survival (intermediate phenotype). 
D) a profound defect in adenine synthesis as two enzymes are missing. 
E) embryonic lethality. 
A) lethal phenotype in media lacking adenine supplementation. 
B) wild-type phenotype,capable of synthesizing adenine. 
C) a weak adenine requirement for survival (intermediate phenotype). 
D) a profound defect in adenine synthesis as two enzymes are missing. 
E) embryonic lethality.

Question 10

While one gene usually specifies one enzyme,which of the following is/are NOT true?

Accepted Answer

A) One gene can specify a single enzyme if that enzyme contains a single type of polypeptide chain. 
B) One gene can specify parts of two enzymes if the enzymes have one type of polypeptide chain in common. 
C) One enzyme may be determined by two genes if the enzyme has two different types of polypeptide chains. 
D) One mutation may cause multiple nutritional requirements if it interferes with the synthesis of an intermediate common to several pathways. 
E) Two mutations in the same gene can never have different effects,even when studied in great biochemical detail. 
A) One gene can specify a single enzyme if that enzyme contains a single type of polypeptide chain. 
B) One gene can specify parts of two enzymes if the enzymes have one type of polypeptide chain in common. 
C) One enzyme may be determined by two genes if the enzyme has two different types of polypeptide chains. 
D) One mutation may cause multiple nutritional requirements if it interferes with the synthesis of an intermediate common to several pathways. 
E) Two mutations in the same gene can never have different effects,even when studied in great biochemical detail.

Question 11

Which of the following are types of posttranslational processing that will not occur in a prokaryote?

Accepted Answer

A) addition of a phosphate group 
B) removal of a phosphate group 
C) addition of a co-factor 
D) cleavage of a mitochondrial targeting sequence 
E) None of the answer options are correct. 
A) addition of a phosphate group 
B) removal of a phosphate group 
C) addition of a co-factor 
D) cleavage of a mitochondrial targeting sequence 
E) None of the answer options are correct.

Question 12

You believe you created a protein translation machine that operates outside of the cell.If you combine the "translation machine" with an mRNA and charged tRNAs,a protein product is generated.However,as you do additional experiments,you find that though the correct amino acids are joined together,the protein is nonfunctional.What might be missing in your system,causing these synthesized proteins to lack activity?

Accepted Answer

Proteins depend on three-dimensional str

Question 13

In vitro (in a test tube)translation of a synthetic RNA with the repeating sequence (AGA)20 would produce which of the following?

Accepted Answer

A) polypeptides containing arginine,polypeptides containing glutamic acid,and polypeptides containing lysine 
B) polypeptides containing arginine 
C) polypeptides containing a mixture of amino acids (mostly arginine,glutamic acid,and lysine) 
D) no translation product because the translation start site was not included on the RNA 
E) polypeptides starting with methionine,followed by arginine additions 
A) polypeptides containing arginine,polypeptides containing glutamic acid,and polypeptides containing lysine 
B) polypeptides containing arginine 
C) polypeptides containing a mixture of amino acids (mostly arginine,glutamic acid,and lysine) 
D) no translation product because the translation start site was not included on the RNA 
E) polypeptides starting with methionine,followed by arginine additions

Question 14

Which codons are susceptible to being converted to a "UAG" STOP codon with only a single nucleotide mutation?

Accepted Answer

UGG (Trp),UCG (Ser),

Question 15

You found a mouse gene sequence containing an open reading frame that should produce a 43 kDa protein.You express this protein in cultured mouse cells by transforming the cells with a plasmid bearing your gene of interest.When you isolate proteins from these cells and probe for your protein of interest,you find that the detected protein is 49 kDa.Why might your protein be larger than expected when analyzed by immunoblot?

Accepted Answer

In eukaryotic cells,post-translational m

Question 16

Diagram the process of translation,showing the sequential steps of tRNA entry,amino acid transfer,and eventual tRNA release.This is a multi-step process,so you will need to diagram at least three consecutive steps as a new tRNA moves through this process.

Accepted Answer

Step 1: tRNA Entry
- The ribosome binds

Question 17

Fibrous proteins contain a structure that is:

Accepted Answer

A) rounded and compact. 
B) globular. 
C) only comprised of secondary structure. 
D) linear/extended. 
E) random and variable. 
A) rounded and compact. 
B) globular. 
C) only comprised of secondary structure. 
D) linear/extended. 
E) random and variable.

Question 18

The use of proflavin-induced mutations (like FCO)in the rII genome was found to experimentally support a three-nucleotide explanation for the genetic code because:

Accepted Answer

A) an insertion mutation could be suppressed by a deletion mutation. 
B) the rII genes are easier to mutate than other genes. 
C) proflavin was an inexpensive mutagenic compound. 
D) a gene with three insertions or three deletions could sometimes provide a functional protein. 
E) the rII gene encoded a protein with exactly the correct number of amino acids,as would be explained by a three nucleotide genetic code. 
A) an insertion mutation could be suppressed by a deletion mutation. 
B) the rII genes are easier to mutate than other genes. 
C) proflavin was an inexpensive mutagenic compound. 
D) a gene with three insertions or three deletions could sometimes provide a functional protein. 
E) the rII gene encoded a protein with exactly the correct number of amino acids,as would be explained by a three nucleotide genetic code.

Question 19

A tRNA with the anticodon 3′-ACC-5′ would carry the amino acid:

Accepted Answer

A) phenylalanine. 
B) tyrosine. 
C) serine. 
D) threonine. 
E) tryptophan. 
A) phenylalanine. 
B) tyrosine. 
C) serine. 
D) threonine. 
E) tryptophan.

Question 20

In Neurospora,a linear biochemical pathway synthesizes an amino acid Z.E1,E2,and E3 are enzymes that catalyze the three reactions.    Null mutants for the enzyme E2 gene will grow on minimal medium supplemented with compounds:

Accepted Answer

A) W or X. 
B) Y or Z. 
C) W or X or Y or Z. 
D) Z only. 
E) W only. 
A) W or X. 
B) Y or Z. 
C) W or X or Y or Z. 
D) Z only. 
E) W only.

Why is the attachment of an amino acid to the correct tRNA considered to be such an important step in protein synthesis?

DNA probes are often synthesized based on knowledge of the protein produced by a gene.What might be a potential problem of synthesizing DNA probes in this manner?

Describe how it was determined that the genetic code was not overlapping.What evidence was used to support this?

What is post-translational processing? Why is it important for protein function?

The ribosome is the primary site of:

How does a nonsense suppressor mutation prevent amber mutants from terminating their polypeptides prematurely?

The proteome for humans is about 70,000 proteins whereas only 21,000 protein-coding genes have been discovered.Which statement could explain this?

Francis Crick proposed "adapter" molecules to serve as an intermediary between mRNA and the synthesis of protein.Key to any model of how RNA is "read" in the process of protein synthesis would be a consideration of how:

Two gametes,each carrying a mutant recessive allele for a different gene/enzyme in the adenine biosynthetic pathway,come together to form a diploid embryo.The individual derived from this embryo will display a:

While one gene usually specifies one enzyme,which of the following is/are NOT true?

Which of the following are types of posttranslational processing that will not occur in a prokaryote?

In vitro (in a test tube)translation of a synthetic RNA with the repeating sequence (AGA)₂₀ would produce which of the following?

Which codons are susceptible to being converted to a "UAG" STOP codon with only a single nucleotide mutation?

Diagram the process of translation,showing the sequential steps of tRNA entry,amino acid transfer,and eventual tRNA release.This is a multi-step process,so you will need to diagram at least three consecutive steps as a new tRNA moves through this process.

Fibrous proteins contain a structure that is:

The use of proflavin-induced mutations (like FCO)in the rII genome was found to experimentally support a three-nucleotide explanation for the genetic code because:

A tRNA with the anticodon 3′-ACC-5′ would carry the amino acid:

In Neurospora,a linear biochemical pathway synthesizes an amino acid Z.E1,E2,and E3 are enzymes that catalyze the three reactions. Null mutants for the enzyme E2 gene will grow on minimal medium supplemented with compounds:

The Genetics Revolution

Single-Gene Inheritance

Independent Assortment of Genes

Mapping Eukaryote Chromosomes by Recombination

The Genetics of Bacteria and Their Viruses

Gene Interaction

Dna: Structure and Replication

Rna: Transcription and Processing

Gene Isolation and Manipulation

Regulation of Gene Expression in Bacteria and Their Viruses

Regulation of Gene Expression in Eukaryotes

The Genetic Control of Development

Genomes and Genomics

The Dynamic Genome: Transposable Elements

Mutation, Repair, and Recombination

Large-Scale Chromosomal Changes

Population Genetics

The Inheritance of Complex Traits

Evolution of Genes and Traits

Filters

Exam 9: Proteins and Their Synthesis

Why is the attachment of an amino acid to the correct tRNA considered to be such an important step in protein synthesis?

DNA probes are often synthesized based on knowledge of the protein produced by a gene.What might be a potential problem of synthesizing DNA probes in this manner?

Describe how it was determined that the genetic code was not overlapping.What evidence was used to support this?

What is post-translational processing? Why is it important for protein function?

The ribosome is the primary site of:

How does a nonsense suppressor mutation prevent amber mutants from terminating their polypeptides prematurely?

The proteome for humans is about 70,000 proteins whereas only 21,000 protein-coding genes have been discovered.Which statement could explain this?

Francis Crick proposed "adapter" molecules to serve as an intermediary between mRNA and the synthesis of protein.Key to any model of how RNA is "read" in the process of protein synthesis would be a consideration of how:

Two gametes,each carrying a mutant recessive allele for a different gene/enzyme in the adenine biosynthetic pathway,come together to form a diploid embryo.The individual derived from this embryo will display a:

While one gene usually specifies one enzyme,which of the following is/are NOT true?

Which of the following are types of posttranslational processing that will not occur in a prokaryote?

In vitro (in a test tube)translation of a synthetic RNA with the repeating sequence (AGA)20 would produce which of the following?

Which codons are susceptible to being converted to a "UAG" STOP codon with only a single nucleotide mutation?

Diagram the process of translation,showing the sequential steps of tRNA entry,amino acid transfer,and eventual tRNA release.This is a multi-step process,so you will need to diagram at least three consecutive steps as a new tRNA moves through this process.

Fibrous proteins contain a structure that is:

The use of proflavin-induced mutations (like FCO)in the rII genome was found to experimentally support a three-nucleotide explanation for the genetic code because:

A tRNA with the anticodon 3′-ACC-5′ would carry the amino acid:

In Neurospora,a linear biochemical pathway synthesizes an amino acid Z.E1,E2,and E3 are enzymes that catalyze the three reactions. Null mutants for the enzyme E2 gene will grow on minimal medium supplemented with compounds:

The Genetics Revolution

Single-Gene Inheritance

Independent Assortment of Genes

Mapping Eukaryote Chromosomes by Recombination

The Genetics of Bacteria and Their Viruses

Gene Interaction

Dna: Structure and Replication

Rna: Transcription and Processing

Gene Isolation and Manipulation

Regulation of Gene Expression in Bacteria and Their Viruses

Regulation of Gene Expression in Eukaryotes

The Genetic Control of Development

Genomes and Genomics

The Dynamic Genome: Transposable Elements

Mutation, Repair, and Recombination

Large-Scale Chromosomal Changes

Population Genetics

The Inheritance of Complex Traits

Evolution of Genes and Traits

Filters

In vitro (in a test tube)translation of a synthetic RNA with the repeating sequence (AGA)₂₀ would produce which of the following?