AQA · A-Level · Biology
Course version: 7402 · Version from Sept 2016
Sequencing projects have read the genomes of a wide range of organisms,…
Full specification wording
Using genome projects (A-level only): Sequencing projects have read the genomes of a wide range of organisms, including humans.
The genome is the complete set of genes in a cell, or all the DNA in a cell, including non-coding DNA.
Checked against the AQA 7402 specification (opens in a new tab) on .
- Point 1 of 5
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The genome is the complete set of genes in a cell, or all the DNA in a cell, including non-coding DNA. Sequencing determines the order of bases along that DNA. The Human Genome Project mapped the vast majority of the human genome between 1990 and 2003. Genomes of bacteria, viruses, and model organisms like the fruit fly have also been sequenced, many concurrently or earlier. Comparing sequences between species measures how closely related organisms are; more similar sequences imply a more recent common ancestor. This evidence has led to species originally grouped by appearance being reclassified and renamed based on their evolutionary relationships.
What earns the marks
- Defining the genome as the complete set of genes in a cell, or all the DNA in a cell or organism.
- Sequencing being the determination of the order of bases in the DNA.
- Using base sequence comparison between species as evidence of how closely related they are.
- A named consequence of sequencing, such as species being reclassified or renamed on new sequence evidence.
- A named use of a sequenced genome within a species, such as identifying alleles linked to disease risk.
Common mistakes and how to put them right
Defining the genome as all the DNA in a species or a population, rather than per cell or per organism.
Defining the genome as the proteins an organism can produce, which confuses it with the proteome, or the expressed genes, which is the transcriptome.
Saying sequencing counts the genes, rather than reading the order of the bases.
Claiming the Human Genome Project identified all human proteins, when a genome does not give the proteome directly in a eukaryote.
Exam tips
- The definition of a genome is specific: the complete set of genes in a cell, or all the DNA in a cell.
- Say 'cell' or 'organism', never 'species' or 'population', in a genome definition.
- If asked why classification has changed, refer to specific techniques like DNA or RNA base sequencing providing new evidence.
Try the lesson
The start of the Using genome projects (A-level only): Sequencing projects have read the genomes of a wide range of organisms, including humans. lesson, made from checked teaching notes for this specification point.
Have a go first
What is the primary achievement of large-scale genome sequencing projects?
Listen
The genome is the complete set of genes in a cell, or all the DNA in a cell, including non-coding DNA. Sequencing determines the order of bases along that DNA. The Human Genome Project mapped the vast majority of the human genome between 1990 and 2003. Genomes of bacteria, viruses, and model organisms like the fruit fly have also been sequenced, many concurrently or earlier. Comparing sequences between species measures how closely related organisms are; more similar sequences imply a more recent common ancestor. This evidence has led to species originally grouped by appearance being reclassified and renamed based on their evolutionary relationships. A strong answer earns marks for these points. defining the genome as the complete set of genes in a cell, or all the DNA in a cell or organism. sequencing being the determination of the order of bases in the DNA. using base sequence comparison between species as evidence of how closely related they are. a named consequence of sequencing, such as species being reclassified or renamed on new sequence evidence. Exam tip: The definition of a genome is specific: the complete set of genes in a cell, or all the DNA in a cell.
Key words
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genome
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DNA base sequencing
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Human Genome Project
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comparing species
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See every definition
- genome
- The complete set of genes in a cell, or all the DNA in a cell, including non-coding DNA.
- DNA base sequencing
- The determination of the order of bases along the DNA.
- Human Genome Project
- Mapped the vast majority of the human genome between 1990 and 2003.
- comparing species
- Comparing sequences between species measures how closely related organisms are; more similar sequences imply a more recent common ancestor.
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