Biology by Bradford
4.1.A, 4.1.BFour ways cells signal
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4.1 Cell Communication: revision map
The subtopic in the middle and four tasks round it: label a diagram, complete a table and fill 9 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.
Cell Communication
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.
Name4.1.AWhy cells signal
A signal is sent by a cell and detected by a target cell that has the right . In a multicellular body signals coordinate growth, development and the response to injury or infection. Single cells signal too: yeast cells release mating factors to find a partner, and bacteria sense the density of their population by quorum sensing, releasing and detecting small molecules, so that a whole group can switch on a behavior, such as making biofilms or light, at once.
Topic 4.1Cell Communication
4.1.ASignal and distance
| Type | Signal travels | Example |
|---|---|---|
| back to the cell that made it | a cell stimulating its own growth | |
| a short distance, to neighbors | a neurotransmitter crossing a synapse | |
| a long way, in the blood | insulin from the pancreas | |
| Direct contact | through junctions or by touching | gap junctions; plasmodesmata in plants |
4.1.BSignals shape the response
A target cell's response depends on the signal it receives and the receptors it carries. Two cells can receive the same ligand and respond differently, and a cell may respond to several signals at once, adding up their effects. Signals can change gene expression, alter the activity of enzymes, or cause a cell to move, divide or die: the last of these is .
Word bank apoptosisautocrineAutocrinedirect contactendocrineEndocrineparacrineParacrinereceptor
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelFour ways cells signal
- autocrine
- paracrine
- endocrine
- direct contact
TableSignal and distance
Type Signal travels Example Autocrine back to the cell that made it a cell stimulating its own growth Paracrine a short distance, to neighbors a neurotransmitter crossing a synapse Endocrine a long way, in the blood insulin from the pancreas Direct contact through junctions or by touching gap junctions; plasmodesmata in plants GapsWhy cells signal
A signal is sent by a cell and detected by a target cell that has the right receptor. In a multicellular body signals coordinate growth, development and the response to injury or infection. Single cells signal too: yeast cells release mating factors to find a partner, and bacteria sense the density of their population by quorum sensing, releasing and detecting small molecules, so that a whole group can switch on a behavior, such as making biofilms or light, at once.
GapsSignals shape the response
A target cell's response depends on the signal it receives and the receptors it carries. Two cells can receive the same ligand and respond differently, and a cell may respond to several signals at once, adding up their effects. Signals can change gene expression, alter the activity of enzymes, or cause a cell to move, divide or die: the last of these is apoptosis.