Lesson 3.8.2.1.1

3.8.2.1.1 Non-translated DNA in the cell Quiz: AQA Biology, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.8.2.1.1, Non-translated DNA in the cell: 20 multiple choice questions for the AQA Biology (7402), Unit 8: The control of gene expression, written with Revision Ninja.

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The 20 questions

  1. Most of a cell's DNA is:

    • Copied into tRNA molecules
    • Translated into protein in every cell
    • Not translated into protein
    • Made of genes for ribosomal RNA only

  2. The genome of a cell is best defined as:

    • The sequence of amino acids in one polypeptide
    • The set of enzymes that catalyse respiration
    • The full range of proteins the cell can produce
    • The complete set of genes in the cell

  3. The proteome of a cell is best defined as:

    • The sum of all non-coding DNA sequences
    • The full range of proteins that the cell is able to produce
    • The complete set of genes carried by the cell
    • The set of mRNA molecules present at one moment

  4. Which sequences are removed from pre-mRNA during splicing?

    • Exons
    • Promoters
    • Codons
    • Introns

  5. In eukaryotes, transcription produces which molecule before splicing?

    • tRNA
    • Ribosomal protein
    • Pre-mRNA
    • Polypeptide

  6. Which of these is a type of non-coding DNA?

    • Multiple repeats of short sequences
    • Exons only
    • Codons that code for amino acids
    • Start codons only

  7. Non-translated DNA in eukaryotes includes:

    • Only the sequences that code for enzymes
    • Regulatory sequences and non-coding repeats
    • Only the sequences that code for tRNA
    • Only the codons for the twenty amino acids

  8. A gene is 1200 bases long and 400 bases are exons. What proportion of the gene is intron?

    • 40 per cent
    • 33 per cent
    • 80 per cent
    • 67 per cent

  9. Why might knowing the genome of a complex organism not reveal its proteome?

    • The genome is always identical to the proteome, so every gene in it is expressed as a protein in every cell of the body
    • Non-coding DNA and regulatory genes mean that the genome does not directly show which proteins are made
    • Proteins are made directly from DNA without any mRNA, so the genome sequence alone is enough to show the whole proteome
    • Complex organisms have very few genes, so the genome contains too little information to show which proteins are made at all

  10. Which statement about eukaryotic transcription is correct?

    • The primary transcript contains introns, which must be removed by splicing to make mRNA
    • The primary transcript is mRNA that is translated directly by ribosomes, so no splicing or processing is needed in eukaryotic cells
    • Splicing happens before any DNA is copied, so the introns are removed from the gene before the transcription process begins
    • Transcription produces only tRNA molecules, which are then spliced to form the mRNA that carries the code for the protein

  11. Which term describes a DNA sequence that does not code for protein but influences gene expression?

    • An exon
    • A ribosomal binding site on tRNA
    • A regulatory sequence
    • A codon

  12. A gene has 5 exons totalling 600 bases and 4 introns totalling 900 bases. What is the length of the pre-mRNA produced?

    • 2100 bases
    • 1500 bases
    • 600 bases
    • 900 bases

  13. Why are introns absent from mature mRNA?

    • They are removed by splicing before the mRNA leaves the nucleus
    • They are destroyed by ribosomes during translation
    • They are converted into tRNA molecules
    • They are never transcribed from the DNA

  14. Which molecule is produced by transcription before splicing in eukaryotes?

    • Ribosomal RNA only
    • tRNA
    • Pre-mRNA
    • Polypeptide

  15. Why is the presence of non-coding DNA a challenge when predicting proteins from a genome?

    • Only the coding regions produce proteins, so identifying them from sequence alone is harder
    • Non-coding DNA is always translated into proteins, so every base in the genome contributes to the proteome
    • Non-coding DNA prevents transcription in every cell of the body, so the genome can never be read for any of its genes in any tissue
    • Non-coding DNA contains all the genes for ribosomes, so the ribosomes of a complex organism are the only things that the genome encodes

  16. A gene has three exons of 300, 250 and 150 bases and two introns of 400 and 500 bases. What percentage of the pre-mRNA remains in the mature mRNA?

    • 56 per cent
    • 19 per cent
    • 44 per cent
    • 81 per cent

  17. A claim states that most DNA is useless because it does not code for protein. What is the best evaluation?

    • Non-coding DNA may have regulatory or structural roles, so the claim is an overstatement
    • The claim is correct because non-coding DNA is always lost during division
    • The claim is false because all DNA codes for protein in complex organisms
    • The claim is correct because non-coding DNA never affects gene expression

  18. Why do regulatory genes complicate the relationship between the genome and the proteome?

    • Regulatory genes control which other genes are expressed and when, so the same genome can give different proteomes
    • Regulatory genes are copied only once during development and are never expressed, so they have no effect on the proteome at all
    • Regulatory genes make proteins directly from the genome without any mRNA, so timing and amount of each protein are fixed by the DNA
    • Regulatory genes make the genome identical to the proteome, so every gene in the genome is expressed in the same way in every cell

  19. Which statement about eukaryotic gene structure is correct?

    • Genes are always identical to their mRNA
    • Genes contain coding exons separated by non-coding introns
    • Genes contain only coding sequences and no introns
    • Genes are made of protein and not DNA

  20. Which statement about introns is correct?

    • Introns code for the amino acids of the polypeptide
    • Introns are found only in prokaryotic genes
    • Introns are translated into protein before splicing takes place
    • Introns are transcribed into pre-mRNA but are removed before translation

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