Question 1

The central dogma of gene expression can be summarised as

Accepted Answer

A)  DNA $\rightarrow$ RNA $\rightarrow$Protein. 
B)  RNA $\rightarrow$ DNA $\rightarrow$ Protein. 
C)  Protein $\rightarrow$ DNA $\rightarrow$RNA. 
D)  DNA $\rightarrow$ Protein $\rightarrow$RNA. 
E)  RNA $\rightarrow$ Protein $\rightarrow$DNA. 
A)  DNA $\rightarrow$ RNA $\rightarrow$Protein. 
B)  RNA $\rightarrow$ DNA $\rightarrow$ Protein. 
C)  Protein $\rightarrow$ DNA $\rightarrow$RNA. 
D)  DNA $\rightarrow$ Protein $\rightarrow$RNA. 
E)  RNA $\rightarrow$ Protein $\rightarrow$DNA.

Question 2

Which of the following statements about the genetic code is the most CORRECT?

Accepted Answer

A)  Protists use a simplified genetic code. 
B)  Genetic codes are similar in most living organisms. 
C)  Plants and animals have markedly different genetic codes. 
D)  Each amino acid has a unique genetic code. 
E)  All organisms originated with the same genetic code but genetic drift has introduced variation. 
A)  Protists use a simplified genetic code. 
B)  Genetic codes are similar in most living organisms. 
C)  Plants and animals have markedly different genetic codes. 
D)  Each amino acid has a unique genetic code. 
E)  All organisms originated with the same genetic code but genetic drift has introduced variation.

Question 3

Which of the following statements about RNA is CORRECT?

Accepted Answer

A)  Eukaryote mRNA molecules are longer than prokaryote mRNAs. 
B)  Amino acids link to the 5' end of the tRNA. 
C)  Eukaryote mRNA molecules are polycistronic. 
D)  tRNA is activated by aminoacylation. 
E)  mRNA translation is initiated by binding the mRNA to tRNA. 
A)  Eukaryote mRNA molecules are longer than prokaryote mRNAs. 
B)  Amino acids link to the 5' end of the tRNA. 
C)  Eukaryote mRNA molecules are polycistronic. 
D)  tRNA is activated by aminoacylation. 
E)  mRNA translation is initiated by binding the mRNA to tRNA.

Question 4

In eukaryotic cells, transcription generates

Accepted Answer

A)  mRNA. 
B)  ribosome subunits. 
C)  complementary DNA. 
D)  3 forms of RNA. 
E)  aminoacyl-tRNA. 
A)  mRNA. 
B)  ribosome subunits. 
C)  complementary DNA. 
D)  3 forms of RNA. 
E)  aminoacyl-tRNA.

Question 5

An mRNA 2650 base pairs long was transcribed from a gene containing 3782 base pairs. The most likely explanation would be that

Accepted Answer

A)  the gene sequence was altered and now contains a nonsense mutation. 
B)  the gene sequence was altered and now contains a missense mutation. 
C)  splicing during transcription removed introns from the sequence. 
D)  the gene sequence was altered and now contains a nonsense mutation and splicing during transcription removed introns from the sequence. 
E)  the gene sequence was altered and now contains a missense mutation and splicing during transcription removed introns from the sequence. 
A)  the gene sequence was altered and now contains a nonsense mutation. 
B)  the gene sequence was altered and now contains a missense mutation. 
C)  splicing during transcription removed introns from the sequence. 
D)  the gene sequence was altered and now contains a nonsense mutation and splicing during transcription removed introns from the sequence. 
E)  the gene sequence was altered and now contains a missense mutation and splicing during transcription removed introns from the sequence.

Question 6

The 'one gene-one enzyme' hypothesis is INCORRECT

Accepted Answer

A)  because not all enzymes are produced from just one gene. 
B)  because genes code for polypeptides. 
C)  because not all proteins are enzymes. 
D)  because some proteins are structural. 
E)  for all of these reasons. 
A)  because not all enzymes are produced from just one gene. 
B)  because genes code for polypeptides. 
C)  because not all proteins are enzymes. 
D)  because some proteins are structural. 
E)  for all of these reasons.

Question 7

The process by which an mRNA species is converted to a protein is called

Accepted Answer

A)  complementarity. 
B)  elongation. 
C)  gene transfer. 
D)  translation. 
E)  transcription. 
A)  complementarity. 
B)  elongation. 
C)  gene transfer. 
D)  translation. 
E)  transcription.

Question 8

During protein synthesis, the mRNA

Accepted Answer

A)  fits into a groove formed between the large and small ribosomal subunits. 
B)  is exposed to the A and P sites. 
C)  is bound underneath the small ribosomal subunit, allowing tRNAs access to the codons. 
D)  fits into a groove formed between the large and small ribosomal units and is exposed to the A and P sites. 
E)  is exposed to the A and P sites and is bound underneath the small ribosomal subunit, allowing tRNAs access to the codons. 
A)  fits into a groove formed between the large and small ribosomal subunits. 
B)  is exposed to the A and P sites. 
C)  is bound underneath the small ribosomal subunit, allowing tRNAs access to the codons. 
D)  fits into a groove formed between the large and small ribosomal units and is exposed to the A and P sites. 
E)  is exposed to the A and P sites and is bound underneath the small ribosomal subunit, allowing tRNAs access to the codons.

Question 9

A polycistronic unit is

Accepted Answer

A)  a eukaryotic transcription unit that encodes for more than one protein. 
B)  a bacterial transcription unit that encodes for more than one protein. 
C)  a bacterial or eukaryotic transcription unit that encodes for more than one protein. 
D)  comprised of mRNA coding regions immediately adjacent to each other. 
E)  a viral transcription unit that encodes for more than one protein. 
A)  a eukaryotic transcription unit that encodes for more than one protein. 
B)  a bacterial transcription unit that encodes for more than one protein. 
C)  a bacterial or eukaryotic transcription unit that encodes for more than one protein. 
D)  comprised of mRNA coding regions immediately adjacent to each other. 
E)  a viral transcription unit that encodes for more than one protein.

Question 10

Double-stranded regions of RNA

Accepted Answer

A)  are not as stable as double-stranded DNA. 
B)  unlike DNA, hydrogen bond in parallel strands. 
C)  can form between two complementary regions within one molecule of RNA. 
D)  do not occur. 
E)  are frequently observed in isolated RNA, but probably do not occur in cells. 
A)  are not as stable as double-stranded DNA. 
B)  unlike DNA, hydrogen bond in parallel strands. 
C)  can form between two complementary regions within one molecule of RNA. 
D)  do not occur. 
E)  are frequently observed in isolated RNA, but probably do not occur in cells.

Question 11

Which of the following is a difference in transcription of DNA between prokaryotes and eukaryotes? In prokaryotes

Accepted Answer

A)  translation into polypeptides commences while mRNA is being transcribed. 
B)  there is only one type of RNA polymerase. 
C)  transcript mRNAs are polycistronic. 
D)  transcript mRNAs undergo processing after translation. 
E)  All of the answers are differences. 
A)  translation into polypeptides commences while mRNA is being transcribed. 
B)  there is only one type of RNA polymerase. 
C)  transcript mRNAs are polycistronic. 
D)  transcript mRNAs undergo processing after translation. 
E)  All of the answers are differences.

Question 12

tRNA molecules

Accepted Answer

A)  transfer proteins out of the cytoplasm. 
B)  covalently bond to amino acids. 
C)  transfer information between DNA and the ribosomes. 
D)  covalently bond to nucleotides of mRNA. 
E)  bind to the growing polypeptide chain. 
A)  transfer proteins out of the cytoplasm. 
B)  covalently bond to amino acids. 
C)  transfer information between DNA and the ribosomes. 
D)  covalently bond to nucleotides of mRNA. 
E)  bind to the growing polypeptide chain.

Question 13

Most eukaryotes use an open reading frame in gene expression. This means that

Accepted Answer

A)  only one protein can be encoded from the same region of DNA. 
B)  protein synthesis begins with the assembly of an initiation complex. 
C)  all protein sequences start with the same amino acid. 
D)  different proteins can be encoded from each of the complementary strands of DNA. 
E)  many amino acids are coded for by synonymous codons. 
A)  only one protein can be encoded from the same region of DNA. 
B)  protein synthesis begins with the assembly of an initiation complex. 
C)  all protein sequences start with the same amino acid. 
D)  different proteins can be encoded from each of the complementary strands of DNA. 
E)  many amino acids are coded for by synonymous codons.

Question 14

In prokaryotes, the first amino acid in protein synthesis is always

Accepted Answer

A)  methionine. 
B)  N-formyl methionine. 
C)  an acidic amino acid. 
D)  the first amino acid of the signal sequence. 
E)  L-methionine. 
A)  methionine. 
B)  N-formyl methionine. 
C)  an acidic amino acid. 
D)  the first amino acid of the signal sequence. 
E)  L-methionine.

Question 15

The one gene-one polypeptide hypothesis states that

Accepted Answer

A)  each protein produced by a cell is coded for by a single gene. 
B)  one gene can only possibly produce one protein product. 
C)  each gene codes for one polypeptide. 
D)  each cell only has one copy of each gene for each polypeptide. 
E)  each gene codes for one enzyme which may be composed of polypeptides. 
A)  each protein produced by a cell is coded for by a single gene. 
B)  one gene can only possibly produce one protein product. 
C)  each gene codes for one polypeptide. 
D)  each cell only has one copy of each gene for each polypeptide. 
E)  each gene codes for one enzyme which may be composed of polypeptides.

Question 16

The translocation reaction involves

Accepted Answer

A)  the transfer of the growing peptide chain from the P site to the single amino acid on the tRNA in the A site. 
B)  the displacement of the uncharged tRNA from the P site into the cytosol. 
C)  the movement of the ribosome three bases along the mRNA in the 5' to 3' direction. 
D)  the binding of the next aminoacyl-tRNA to the vacant A site. 
E)  All of the answers are correct. 
A)  the transfer of the growing peptide chain from the P site to the single amino acid on the tRNA in the A site. 
B)  the displacement of the uncharged tRNA from the P site into the cytosol. 
C)  the movement of the ribosome three bases along the mRNA in the 5' to 3' direction. 
D)  the binding of the next aminoacyl-tRNA to the vacant A site. 
E)  All of the answers are correct.

Question 17

The three forms of RNA differ in that

Accepted Answer

A)  rRNA is not transcribed from DNA. 
B)  only mRNA in translated. 
C)  only mRNA requires a primer for transcription. 
D)  all tRNAs are identical. 
E)  both rRNA and tRNA are components of ribosomes, but mRNA is not. 
A)  rRNA is not transcribed from DNA. 
B)  only mRNA in translated. 
C)  only mRNA requires a primer for transcription. 
D)  all tRNAs are identical. 
E)  both rRNA and tRNA are components of ribosomes, but mRNA is not.

Question 18

Which of the following is a specific sequence that binds RNA polymerase?

Accepted Answer

A)  A reading frame 
B)  An operon 
C)  A transcription unit 
D)  A promoter 
E)  An intron 
A)  A reading frame 
B)  An operon 
C)  A transcription unit 
D)  A promoter 
E)  An intron

Question 19

Signal sequences

Accepted Answer

A)  tell the cell that a protein needs to be modified before it is functional. 
B)  are recognised and bound by specific receptors at the correct cellular site for the polypeptide. 
C)  are never removed because they are a part of the final, functional protein. 
D)  tell the ribosome where to start and stop translation. 
E)  are added after protein synthesis. 
A)  tell the cell that a protein needs to be modified before it is functional. 
B)  are recognised and bound by specific receptors at the correct cellular site for the polypeptide. 
C)  are never removed because they are a part of the final, functional protein. 
D)  tell the ribosome where to start and stop translation. 
E)  are added after protein synthesis.

Question 20

A cell lacking peptidyl transferase would NOT be able to make proteins because

Accepted Answer

A)  N-formyl methionine-charged tRNA would not bind to the initiator codon. 
B)  peptide bonds between the carboxyl group of the incoming amino acid to the amino group of the growing polypeptide chain would not be catalysed. 
C)  peptide bonds between the amino group of the incoming amino acid to the carboxyl group of the growing polypeptide chain would not be catalysed. 
D)  the termination codon would not be recognised. 
E)  the growing peptide would not interact with the specific tRNA. 
A)  N-formyl methionine-charged tRNA would not bind to the initiator codon. 
B)  peptide bonds between the carboxyl group of the incoming amino acid to the amino group of the growing polypeptide chain would not be catalysed. 
C)  peptide bonds between the amino group of the incoming amino acid to the carboxyl group of the growing polypeptide chain would not be catalysed. 
D)  the termination codon would not be recognised. 
E)  the growing peptide would not interact with the specific tRNA.

Exam 11: The Genetic Code

The central dogma of gene expression can be summarised as

Which of the following statements about the genetic code is the most CORRECT?

Which of the following statements about RNA is CORRECT?

In eukaryotic cells, transcription generates

An mRNA 2650 base pairs long was transcribed from a gene containing 3782 base pairs. The most likely explanation would be that

The 'one gene-one enzyme' hypothesis is INCORRECT

The process by which an mRNA species is converted to a protein is called

During protein synthesis, the mRNA

A polycistronic unit is

Double-stranded regions of RNA

Which of the following is a difference in transcription of DNA between prokaryotes and eukaryotes? In prokaryotes

tRNA molecules

Most eukaryotes use an open reading frame in gene expression. This means that

In prokaryotes, the first amino acid in protein synthesis is always

The one gene-one polypeptide hypothesis states that

The translocation reaction involves

The three forms of RNA differ in that

Which of the following is a specific sequence that binds RNA polymerase?

Signal sequences

A cell lacking peptidyl transferase would NOT be able to make proteins because

Nature of Molecules

Biomolecules

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Movement Across Membranes

Harvesting Energy

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Mechanisms of Evolution

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The Protists

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