Question 1 Medium
Where in the cell are proteins made?
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Answer: ribosomes
- A ribosome joins amino acids.
- So proteins are made on ribosomes.
DNA, the genome and mutations: GCSE Combined Science Biology practice questions
A second set of questions on DNA, the genome and mutations. They are different from the ones on the topic page. Try each, then open the answer and compare your working.
More questions
Question 2 Medium
A DNA strand has the bases T G C. Write the complementary strand.
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Answer: A C G
- T pairs with A.
- G pairs with C, and C pairs with G.
Question 3 Medium
What name is given to a group of three bases that codes for one amino acid?
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Answer: triplet
- Bases are read in groups of three.
- A group of three is a triplet.
Question 4 Hard
A DNA strand has the bases C T A G G. Write the complementary strand.
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Answer: G A T C C
- C pairs with G.
- The pairs give G A T C C.
Question 5 Hard
What name is given to a change in the base sequence of DNA?
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Answer: mutation
- It happens at random.
- It is a mutation.
Question 6 Hard
What determines the shape of a protein?
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Answer: the order of amino acids
- The chain folds in a specific way.
- The sequence decides the shape.
Question 7 Hard
A mutation is in a non-coding region. Give one thing this could change.
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Answer: gene expression
- Non-coding DNA switches genes on and off.
- So it affects gene expression.
Quick checks
Short questions with options. Choose one before you open the answer.
Check 1
What is DNA?
Show answer
A polymer made of two strands in a double helix, carrying genetic information.
Check 2
What is a nucleotide?
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A repeating unit of DNA made of a sugar, a phosphate and a base.
Check 3
Name the four bases in DNA.
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A, C, G and T.
Check 4
Which bases pair together?
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A with T, and C with G.
Check 5
What is a gene?
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A short section of DNA that codes for a protein.
Check 6
How many bases code for one amino acid?
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Three, called a triplet.
Check 7
What is the genome?
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The entire genetic material of an organism.
Check 8
What was the Human Genome Project?
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A project that mapped all the genes of the human genome.
Check 9
Give one use of knowing the human genome.
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Finding genes linked to diseases.
Check 10
Where are proteins made?
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On ribosomes in the cytoplasm.
Check 11
What decides the shape of a protein?
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The order of its amino acids.
Check 12
What is a mutation?
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A random change in the base sequence of DNA.
Check 13
Why do most mutations have little effect?
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Several triplets can code for the same amino acid.
Check 14
What can non-coding DNA do?
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Switch genes on and off.
Check 15
What is a polymer?
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A long molecule made of many repeating units.
Check 16
Where is DNA found in a cell?
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In the chromosomes in the nucleus.
Check 17
What are the units of DNA called?
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Nucleotides.
Check 18
What does a triplet code for?
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One amino acid.
Check 19
What are proteins made from?
Show answer
Chains of amino acids.
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