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4.4 Feedback: 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.

Unit 4 practice questions The whole Unit 4 map

Topic 4.4

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AP Biology · Unit 4 Cell Communication and Cell CycleName

4.4.AA negative feedback loop

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4.4.ANegative and positive feedback

	Negative	Positive
Effect	the response the change	the response the change
Result	keeps a variable near a set point	drives a process to completion
Examples	body temperature; blood glucose; thirst	oxytocin in labor; blood clotting; fruit ripening

Topic 4.4Feedback

4.4.ABlood glucose after a meal

Number the steps in order.

Glucose enters the blood and the level rises above the set point.
Less insulin is released.
Beta cells in the pancreas detect the rise and release insulin.
Blood glucose falls back to the set point.
Liver and muscle cells take up glucose and store it as glycogen.

4.4.AHomeostasis

Organisms keep their internal conditions within a narrow range, which is called . Most of the time this depends on negative feedback: a receptor detects a change, a control center compares it with the set point, and an effector acts to bring it back. In positive feedback, the response moves the system further from its starting state, so it has an end, such as the birth of a baby, and does not keep a steady state.

Word bank control centereffectorhomeostasisincreasesreceptorreducesstimulus

Answer key

Every box on the sheet with its gaps filled in, as the subtopic reads in full.

LabelA negative feedback loop
1. stimulus
2. receptor
3. control center
4. effector

TableNegative and positive feedback

	Negative	Positive
Effect	the response reduces the change	the response increases the change
Result	keeps a variable near a set point	drives a process to completion
Examples	body temperature; blood glucose; thirst	oxytocin in labor; blood clotting; fruit ripening

OrderBlood glucose after a meal
1. Glucose enters the blood and the level rises above the set point.
2. Beta cells in the pancreas detect the rise and release insulin.
3. Liver and muscle cells take up glucose and store it as glycogen.
4. Blood glucose falls back to the set point.
5. Less insulin is released.
GapsHomeostasis
Organisms keep their internal conditions within a narrow range, which is called homeostasis. Most of the time this depends on negative feedback: a receptor detects a change, a control center compares it with the set point, and an effector acts to bring it back. In positive feedback, the response moves the system further from its starting state, so it has an end, such as the birth of a baby, and does not keep a steady state.