AP Biology · Unit 4: Cell Communication and Cell Cycle
4.4 Feedback
In short
The depth of this topic requires distinguishing between negative and positive feedback. For negative feedback, you should know that it maintains homeostasis by reducing the initial stimulus and returning a perturbed system back to its target set point, operating across molecular, cellular, and organismal levels.
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What else do you need to know about Feedback?
For positive feedback, you must understand that it amplifies responses by moving the initiating variable further away from the initial set point, intensifying the stimulus to produce a system change. Illustrative examples that can be used to build understanding include blood sugar regulation by insulin/glucagon (negative feedback), and lactation in mammals, the onset of labor in childbirth, or the ripening of fruit (positive feedback). There are no specific exclusion statements for this topic.
Can you do these?
- I can describe how negative feedback mechanisms return a perturbed system back to its target set point by reducing the initial stimulus.
- I can explain how positive feedback mechanisms amplify responses by moving the variable further from the initial set point to produce system change.
How is Feedback tested on the exam?
This topic is paired with the science practice of Argumentation (Predict the causes or effects of a change in, or disruption to, one or more components in a biological system). On the exam, you may be expected to predict the effect on a cell or organism if there is a disruption in a feedback mechanism. You should be prepared to use claim, evidence, and reasoning to explain how disruptions (such as drugs or chronic diseases) affect these pathways, alter homeostasis, and produce specific symptoms.
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Feedback: common questions
What do you need to know about Feedback for AP Biology?
The depth of this topic requires distinguishing between negative and positive feedback. For negative feedback, you should know that it maintains homeostasis by reducing the initial stimulus and returning a perturbed system back to its target set point, operating across molecular, cellular, and organismal levels.
How is Feedback tested on the AP Biology exam?
This topic is paired with the science practice of Argumentation (Predict the causes or effects of a change in, or disruption to, one or more components in a biological system).
How do I know I have mastered Feedback?
Check you can do each of these: describe how negative feedback mechanisms return a perturbed system back to its target set point by reducing the initial stimulus; explain how positive feedback mechanisms amplify responses by moving the variable further from the initial set point to produce system change.
Where does Feedback fit in AP Biology?
Feedback is topic 4.4 in Unit 4: Cell Communication and Cell Cycle of AP Biology.
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