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Cell communication worksheet: signal transduction and feedback

A free, printable worksheet for high school and AP Biology. Students follow epinephrine from the bloodstream to glycogen breakdown — reception, transduction, response — compare receptor types, and explain negative and positive feedback.

Download the PDF (free)Answer key (Teacher plan)

What's inside

  1. Vocabulary (10 terms)
  2. How cells communicate (2 questions)
  3. The epinephrine pathway (7 questions)
  4. Receptors, responses and changes (4 questions)
  5. Feedback (3 questions)

Teach it with the 3D lesson

Every question matches a step in CytoTour's 3D chapter on cell communication, built from real receptor, G protein and enzyme structures at true size. Read the steps with pictures on cell communication, step by step, or project the lesson in class — Chapter 1 is free, Chapters 5 and 7 are free with an account, and the Teacher plan opens every chapter.

The worksheet

This is the printable sheet (17 questions). Printing this page prints only the worksheet.

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Cell communication

NameDatePeriod

Part 1 · Vocabulary

1. Write the letter of the matching description next to each term.

  1. Ligand
  2. Receptor
  3. Signal transduction
  4. G protein
  5. Second messenger
  6. Kinase
  7. Phosphatase
  8. Hormone
  9. Negative feedback
  10. Positive feedback
  1. ARelaying a signal from the receptor through the cell to a response
  2. BA small molecule, such as cAMP, that carries the signal through the cytoplasm
  3. CSwitched on when it swaps GDP for GTP; it has α, β and γ subunits
  4. DA response that returns a variable toward its set point
  5. EA signal carried in the blood to distant target cells
  6. FAn enzyme that removes phosphate groups
  7. GA response that pushes a variable further from where it started
  8. HA signaling molecule that binds a specific receptor
  9. IAn enzyme that adds phosphate groups from ATP to proteins
  10. JA protein that binds a specific signal and starts the cell's response

Part 2 · How cells communicate

2. Complete the table.

How the signal travelsExample
Direct contact
Local (paracrine)
Long distance (endocrine)

3. What is quorum sensing in bacteria?

Part 3 · The epinephrine pathway

4. Epinephrine changes what happens inside a muscle cell. Does it have to enter the cell?

  1. AYes — it must reach the glycogen
  2. BNo — it binds a receptor on the cell surface, and the signal is relayed inside
  3. CYes — it binds a receptor in the nucleus
  4. DNo — it diffuses through the membrane without binding anything

5. Put the events in order, starting with the hormone. Number them 1–6.

  1. The G protein swaps GDP for GTP
  2. Glycogen is broken down to glucose
  3. Phosphorylase kinase activates glycogen phosphorylase
  4. Adenylyl cyclase makes cAMP
  5. Epinephrine binds the β2-adrenergic receptor
  6. cAMP activates protein kinase A

6. What switches the G protein on?

  1. AIts α subunit binds GTP in place of GDP
  2. BIt is phosphorylated by PKA
  3. CIt binds cAMP
  4. DIt moves into the nucleus

7. cAMP is called a second messenger. What does that mean?

  1. AIt is the second hormone released by the gland
  2. BIt is a small molecule made inside the cell that carries the signal on from the receptor
  3. CIt carries the signal from the cell back to the gland
  4. DIt is a second receptor in the membrane

8. Sort the pathway into its three stages.

What happens in the epinephrine pathway
Reception
Transduction
Response

9. Why can a few hormone molecules make a muscle cell break down a lot of glycogen?

  1. AEach hormone molecule breaks down glycogen itself
  2. BThe signal is amplified: each step activates many molecules of the next
  3. CThe hormone is copied inside the cell
  4. DGlycogen breaks down on its own once the receptor is touched

10. Name three ways the epinephrine signal is switched off inside the cell.

Part 4 · Receptors, responses and changes

11. Complete the table of receptor types.

Where it isWhat happens when the ligand binds
G protein-coupled receptor
Ligand-gated ion channel
Receptor tyrosine kinase
Internal receptor

12. Name four different kinds of response a cell can make to a signal.

13. A toxin keeps Gα stuck with GTP bound. What happens even after the hormone is gone?

  1. ANothing — the signal stops when the hormone leaves
  2. BcAMP keeps being made and the response continues
  3. CThe receptor is destroyed
  4. DPKA stops working

14. How can a mutation in a signaling protein lead to cancer? Use RAS as the example.

Part 5 · Feedback

15. Blood glucose rises after a meal and insulin brings it back down. What kind of feedback is this?

  1. ANegative feedback
  2. BPositive feedback
  3. CNo feedback — just a reaction
  4. DAmplification

16. Describe how insulin and glucagon keep blood glucose near its set point.

17. Why is childbirth an example of positive feedback?