Pearson Edexcel · GCSE · Biology
Course version: 1BI0 · Version from Sept 2016
Describe the genome as the entire DNA of an organism and a gene as a…
Full specification wording
Topic 3 – Genetics: 3.5 Describe the genome as the entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein
The genome is all the DNA in an organism: in a human, that means the DNA in the 46 chromosomes of a body cell, taken together as one complete set of instructions.
Checked against the Pearson Edexcel 1BI0 specification (opens in a new tab) on .
- Point 3 of 20
Study notes
From the checked teaching notes for this specification point.
The idea
The genome is all the DNA in an organism: in a human, that means the DNA in the 46 chromosomes of a body cell, taken together as one complete set of instructions. A gene is a shorter stretch of a DNA molecule, a section of the double helix, and its base sequence codes for one specific protein. So the genome is the whole library and a gene is a single instruction within it. A useful check is scale: a gene is part of a chromosome, a chromosome is part of the genome. When a question asks you to describe, match each term to its definition and reject answers that swap them, for example calling a gene the entire DNA or saying a gene codes for a whole organism.
What earns the marks
- Genome defined as the entire DNA of an organism, not just one chromosome or one gene.
- Gene defined as a section of a DNA molecule, i.e. part of a chromosome.
- A gene codes for a specific protein, so the link between gene and protein product must be stated.
- Correct scale relationship: genes are sections within DNA, and the genome is the complete DNA set.
- Rejecting the swapped definition, where the genome is called a section or a gene called all the DNA.
Common mistakes and how to put them right
Saying a gene is the entire DNA of an organism.
Put it right by stating that the genome is the entire DNA and a gene is only a section of it.
Saying a gene codes for a whole organism or a cell.
Put it right by stating that a gene codes for a specific protein.
Treating DNA and a gene as the same thing.
Put it right by explaining that DNA is the molecule and a gene is a section of that molecule.
Exam tips
- Underline the key words 'entire DNA' and 'specific protein' before choosing an option.
- Eliminate any option that swaps genome and gene definitions.
- Check the scale words: section and entire are opposites, so they cannot describe the same thing.
Try the lesson
The start of the Topic 3 – Genetics: 3.5 Describe the genome as the entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein lesson, made from checked teaching notes for this specification point.
Have a go first
What is meant by the genome of an organism?
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Topic 3 – Genetics: 3.5 Describe the genome as the entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge