Practice Exam 5
VCE Biology Units 1 & 2 | Gene Expression & Protein Synthesis
✎ Complete ALL questions on paper before opening the Model Answers lesson. No notes. Aim for 1 minute per mark.
MULTIPLE CHOICE
Question 1 (1 mark)
Which molecule carries genetic instructions from DNA in the nucleus to the ribosome?
✎ Circle your answer
A) tRNA
B) mRNA
C) rRNA
D) DNA polymerase
Question 2 (1 mark)
During transcription, RNA polymerase reads the DNA template strand in which direction?
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A) 5′ to 3′
B) 3′ to 5′
C) In both directions at once
D) Direction does not matter
Question 3 (1 mark)
Which nitrogenous base is found in RNA but not in DNA?
✎ Circle your answer
A) Adenine
B) Thymine
C) Uracil
D) Guanine
Question 4 (1 mark)
The region of DNA where RNA polymerase binds to begin transcription is called the:
✎ Circle your answer
A) Terminator
B) Promoter
C) Intron
D) Exon
Question 5 (1 mark)
What is the main function of a ribosome?
✎ Circle your answer
A) Store genetic information
B) Synthesise proteins by joining amino acids in a sequence directed by mRNA
C) Copy DNA before cell division
D) Transport oxygen around the cell
Question 6 (1 mark)
Each codon on an mRNA molecule codes for:
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A) A single nucleotide
B) A single amino acid (or a start/stop signal)
C) An entire protein
D) An entire gene
Question 7 (1 mark)
How many nucleotide bases make up one codon?
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A) 1
B) 2
C) 3
D) 4
Question 8 (1 mark)
The genetic code is described as ‘degenerate’ because:
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A) It only functions correctly in humans
B) More than one codon can code for the same amino acid
C) It contains frequent errors
D) It changes randomly between generations
Question 9 (1 mark)
tRNA molecules function by:
✎ Circle your answer
A) Carrying DNA into the nucleus
B) Carrying a specific amino acid to the ribosome and pairing its anticodon with the mRNA codon
C) Carrying mRNA out of the nucleus
D) Forming the large ribosomal subunit only
Question 10 (1 mark)
Which of the following mRNA codons is a stop codon?
✎ Circle your answer
A) AUG
B) UAA
C) UGC
D) GGG
Question 11 (1 mark)
The removal of introns from pre-mRNA and joining of exons before translation is known as:
✎ Circle your answer
A) Transcription
B) Translation
C) Splicing
D) Replication
Question 12 (1 mark)
A structure added to the 5′ end of a pre-mRNA molecule that protects it and helps the ribosome recognise it is called the:
✎ Circle your answer
A) Poly-A tail
B) 5′ cap
C) Intron
D) Anticodon
Question 13 (1 mark)
A mutation in which a single DNA base is substituted for another, without changing the overall reading frame, is called a:
✎ Circle your answer
A) Insertion mutation
B) Deletion mutation
C) Point (substitution) mutation
D) Frameshift mutation
Question 14 (1 mark)
A mutation that changes a codon so that it now specifies a stop signal, causing the protein to be prematurely shortened, is called a:
✎ Circle your answer
A) Silent mutation
B) Missense mutation
C) Nonsense mutation
D) Neutral mutation
Question 15 (1 mark)
The insertion or deletion of one or two nucleotide bases in a gene usually causes a:
✎ Circle your answer
A) Silent mutation
B) Frameshift mutation, altering every codon downstream of the mutation
C) Point mutation only
D) No change to the protein
Question 16 (1 mark)
Which of the following is an example of a mutagen?
✎ Circle your answer
A) Water
B) Glucose
C) Ultraviolet radiation
D) Oxygen gas
Question 17 (1 mark)
A mutation that changes a codon but still results in the same amino acid being produced, due to the degeneracy of the genetic code, is called a:
✎ Circle your answer
A) Nonsense mutation
B) Missense mutation
C) Silent mutation
D) Frameshift mutation
Question 18 (1 mark)
In a eukaryotic cell, where does transcription take place?
✎ Circle your answer
A) Cytoplasm
B) On free ribosomes
C) Nucleus
D) Mitochondria only
Question 19 (1 mark)
In a eukaryotic cell, where does translation take place?
✎ Circle your answer
A) Nucleus
B) Ribosomes, in the cytoplasm or on the rough ER
C) Golgi apparatus
D) Nucleolus only
Question 20 (1 mark)
The process by which the sequence of codons on mRNA is decoded to build a polypeptide chain is called:
✎ Circle your answer
A) Transcription
B) Replication
C) Translation
D) Splicing
SHORT ANSWER
Question 21 (4 marks)
Describe the process of transcription, from RNA polymerase binding to the release of the pre-mRNA molecule.
✎ Write your answer on paper
Question 22 (3 marks)
Outline the three main steps involved in processing a pre-mRNA molecule into a mature mRNA molecule before it leaves the nucleus.
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Question 23 (5 marks)
Describe the process of translation, from the binding of mRNA to the ribosome through to the release of the completed polypeptide.
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Question 24 (4 marks)
Compare mRNA, tRNA and rRNA in terms of their structure and function in protein synthesis.
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Question 25 (4 marks)
Explain the difference between a point (substitution) mutation and a frameshift mutation, including their likely effects on the resulting protein.
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Question 26 (4 marks)
Using an example, distinguish between silent, missense and nonsense mutations.
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Question 27 (3 marks)
Describe two different causes of mutations.
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Question 28 (4 marks)
Explain why the genetic code being described as ‘universal’ and ‘degenerate’ is significant for living organisms.
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EXTENDED RESPONSE
Extended Response 1: Gene Expression Problem
Question 29 (4 marks)
Extended Response 1: Gene Expression Problem (a)
A section of a DNA template strand has the sequence (written 3′ to 5′): TACGGTAACTTGCCA. Determine the mRNA sequence (5′ to 3′) produced by transcription of this template, and use the genetic code to determine the sequence of amino acids in the resulting polypeptide.
✎ Write your answer on paper
Extended Response 1: Gene Expression Problem
Question 30 (3 marks)
Extended Response 1: Gene Expression Problem (b)
A substitution mutation changes the 8th base of the original template strand from A to G. Determine the effect of this mutation on the mRNA codon and the amino acid sequence, and name the type of mutation this represents.
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Extended Response 1: Gene Expression Problem
Question 31 (3 marks)
Extended Response 1: Gene Expression Problem (c)
Instead of a substitution, a single extra nucleotide is inserted into the template strand immediately after the 6th base. Explain the likely effect of this mutation on the polypeptide produced, compared with the effect described in part (b).
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Extended Response 2: Mutation Case Study
Question 32 (2 marks)
Extended Response 2: Mutation Case Study (a)
A research group studying wing colour in a moth species distinguishes between ‘mutations’ and ‘mutagens’ when describing how a new pale-winged variant arose. Distinguish between these two terms, giving one example of each.
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Extended Response 2: Mutation Case Study
Question 33 (4 marks)
Extended Response 2: Mutation Case Study (b)
The pale-wing variant was found to result from the deletion of two nucleotide bases from the middle of the pigment gene. Explain, with reference to the reading frame, why this type of mutation is likely to have a greater effect on the pigment protein than a single nucleotide substitution would.
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Extended Response 2: Mutation Case Study
Question 34 (3 marks)
Extended Response 2: Mutation Case Study (c)
Explain why some mutations that occur in an organism’s DNA have no observable effect on its phenotype.
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✓ Finished? Open the next lesson – Model Answers – to mark your work.
