The big idea: Every body cell has the same genome, but each cell expresses only some of its genes, so its transcriptome and proteome are its own.
- Genome
- All the genes (all the DNA) of a cell.
- Transcriptome
- All the mRNA molecules made in a cell at a given time.
- Proteome
- All the proteins made in a cell at a given time.
The points to remember
- The genome is the same in almost every body cell.
- Each cell transcribes only some genes, so its transcriptome differs from other cells'.
- Different mRNAs are translated, so the proteome differs too.
- Genes every cell needs, such as for respiration enzymes, are expressed in all cells.
Remember it as: Genome: what a cell has. Proteome: what it makes.
Real example: haemoglobin and insulin. A red-blood-cell precursor and a pancreatic beta cell both carry the haemoglobin and insulin genes. Only the precursor makes haemoglobin, and only the beta cell makes insulin.
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
Start Studying Free Full access to Aimnova Pro · cancel anytime
Fixed or changing: The genome stays the same; the transcriptome and proteome change from cell to cell and over time.
| Genome | Transcriptome | Proteome | |
|---|---|---|---|
| Made of | DNA (genes) | mRNA | Proteins |
| Same in all body cells? | Yes | No | No |
| Changes over time? | No | Yes | Yes |
Why they change: A cell switches genes on and off as it develops and as conditions change, for example when a hormone arrives, so its mRNAs and proteins change while its genes do not.
See how examiners mark answers
Answer exam-style questions with model answers. Learn exactly what earns marks and what doesn't.
Try Exam Vault FreeYour first topic is free to keep • No credit card required
How it is asked: 1A items on why two cells with the same DNA differ, and short written answers comparing the genome, transcriptome and proteome.
IB-style questionDistinguish[3 marks]
Distinguish between the genome, the transcriptome and the proteome of a cell.
Model answer plan
See the answer broken into clear points, with guidance on how each point earns marks.