Help students explore gene expression and regulation with this Grade 12 biology worksheet.
Students will review promoters, repressors, transcription, and environmental influences on gene activity.
Gene Expression and Regulation — Practice
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Try these before or after you print the worksheet. The printable asks you to fill in the words. This asks the question underneath them: every cell in you has the same DNA, so why is a liver cell not a neuron?
Question 1 — put them in order
Click these in order, from a gene to a working protein.
Promoter → transcription → translation → protein. Regulation mostly happens at the very first step — control whether polymerase binds and you control everything after.
Question 2
What is the promoter?
Where transcription starts. It is the switch — a gene with an inaccessible promoter is a gene that stays off.
Question 3
What does a repressor do?
Switches it off. It binds the operator and blocks transcription — a brake rather than an accelerator.
Question 4
Every cell in your body has the same DNA. Why is a liver cell different from a nerve cell?
Different genes are switched on. Same instruction book, different pages being read — which is what gene regulation is for.
Question 5
How can the environment affect gene expression?
It changes which genes are active, without changing the genes themselves. Temperature, food and stress can all shift what a cell is expressing.
Question 6 — select all that apply
Select every part involved in controlling whether a gene is expressed, then press Check.
Promoter, repressor and operator. The ribosome builds the protein once the decision has been made, and mitochondria and plasmids are not part of the switch at all.
Think about it
A cell has far more genes than it uses at any moment. Why is that useful rather than wasteful?
A repressor blocks a gene. What would happen if a repressor stopped working?
Identical twins have identical DNA but are not identical people. How does gene regulation help explain that?
Why does regulation mostly happen at the start of transcription rather than later?