Gene Regulation and Development
Transcriptional control, epigenetic change, post-transcriptional regulation, cell differentiation, stem cells and disrupted cell-cycle control.
How to study A-level Biology
Move between scales deliberately: identify the biological process, trace matter or information, use quantitative evidence, then evaluate the method and conclusion.
Core concepts
Concept 1
Cells with the same genome can specialise because different genes are expressed and their products interact in regulatory networks.
Exam cue: Identify the regulatory level before predicting the effect on RNA, protein and phenotype.
Concept 2
Transcription factors, chromatin state, DNA methylation and RNA processing can alter when and how much functional product is made.
Exam cue: Distinguish a DNA sequence change from a potentially reversible epigenetic modification.
Concept 3
Mutations and regulatory disruption can change cell-cycle control, apoptosis, development and disease risk.
Exam cue: Evaluate stem-cell uses by separating biological feasibility, evidence, risk and ethical considerations.
Risk pitfalls and guardrails
Assuming differentiated cells normally lose genes they do not express.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Using epigenetic to mean any environmental effect on phenotype.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Treating cancer as one mutation with one inevitable outcome.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Memory anchors
Gene Expression
Gene expression is the use of genetic information to produce a functional RNA or protein.
Transcription Factor
A transcription factor binds regulatory DNA or other proteins to influence transcription.
Epigenetic Change
An epigenetic change alters gene activity without changing the DNA base sequence.
Differentiation
Stable patterns of gene expression create specialised cell structures and functions.
Tumour Suppressor
A tumour-suppressor gene product normally restrains proliferation, repairs damage or promotes apoptosis.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Why can a liver cell and neurone have different structures despite containing the same genome?
What does a transcription factor do?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
What is Pass Harbor?
Completely free exam prep for 247 UK exams.
- Practice questions
- Flashcards
- Study guides
- Mock exams
- No registration
- No paywall
- Start instantly
“No more expensive exam prep. Quality study tools should be accessible to everyone.”