Biology by Bradford
4.2.A, 4.2.BA cell-surface receptor
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4.2 Introduction to Signal Transduction: revision map
The subtopic in the middle and four tasks round it: label a diagram, complete a table, put a process in order and fill 7 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
Introduction to Signal Transduction
AP Biology ยท Unit 4 Cell Communication and Cell CycleHover over a box to see it. Untick it to leave it off this sheet and its printout.
Name4.2.AThree stages
Number the steps in order.
- The receptor changes shape.
- Response: the cell changes what it does, such as altering gene expression or enzyme activity.
- Transduction: the signal is relayed by a series of molecules inside the cell.
- Reception: a ligand binds to its receptor.
Topic 4.2Introduction to Signal Transduction
4.2.AWhere receptors are
| Cell-surface receptor | Intracellular receptor | |
|---|---|---|
| Ligand | large or polar, cannot cross the membrane | small and , crosses the membrane |
| Location | plasma membrane | cytoplasm or |
| Example ligand | peptide hormones such as insulin | steroid hormones such as estrogen |
| Typical response | a fast change in enzyme activity | a change in gene expression, usually slower |
4.2.BSpecific binding
A receptor has a binding site that fits one ligand, in the way that an enzyme's active site fits its substrate. When the ligand binds, the receptor changes its , and that change starts the transduction pathway. Because only cells with the matching receptor respond, a hormone in the blood affects only its target cells. A molecule that fits the receptor without activating it can block the signal, which is how many drugs work.
Word bank cellular responseligandnonpolarnucleusreceptorrelay moleculeshape
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelA cell-surface receptor
- ligand
- receptor
- relay molecule
- cellular response
OrderThree stages
- Reception: a ligand binds to its receptor.
- The receptor changes shape.
- Transduction: the signal is relayed by a series of molecules inside the cell.
- Response: the cell changes what it does, such as altering gene expression or enzyme activity.
TableWhere receptors are
Cell-surface receptor Intracellular receptor Ligand large or polar, cannot cross the membrane small and nonpolar, crosses the membrane Location plasma membrane cytoplasm or nucleus Example ligand peptide hormones such as insulin steroid hormones such as estrogen Typical response a fast change in enzyme activity a change in gene expression, usually slower GapsSpecific binding
A receptor has a binding site that fits one ligand, in the way that an enzyme's active site fits its substrate. When the ligand binds, the receptor changes its shape, and that change starts the transduction pathway. Because only cells with the matching receptor respond, a hormone in the blood affects only its target cells. A molecule that fits the receptor without activating it can block the signal, which is how many drugs work.