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AP Biology 4.1 Cell Communication Questions

Practise AP Biology 4.1 questions by distinguishing direct contact, local regulators, synaptic signals and long-distance hormone communication.

Syllabus
Effective Fall 2025
Course
AP Biology

Exam points

  • distinguish direct-contact, local-regulator and long-distance hormone signaling
  • identify synaptic chemical communication and endocrine transport to distant targets
  • classify juxtacrine and paracrine signaling from cell-contact or diffusion evidence

Covered syllabus points

4.1.A—Describe the ways that cells can communicate with one another4.1.B—Explain how cells communicate with one another over short and long distances

Question 1

A portion of the human immune system response to an invading pathogen is shown below.

Figure for Question 1 — AP Biology

Macrophages are white blood cells that ingest invading pathogens.

After digesting the pathogen, macrophages present the antigens from the pathogen to helper T cells in the immune system. These helper T cells then secrete chemical signals called cytokines. The cytokines can travel short distances to activate nearby cytotoxic T cells, which will kill infected cells. Some cytokines will activate the enzyme adenylyl cyclase in nearby B cells to produce cyclic AMP (cAMP). cAMP will then activate the production of antibodies in the B cells.

Question (a)

(a)

Part A

Question (i)

(i)
Figure for Question (i) — AP Biology

Describe the characteristics of juxtacrine signaling.

Question (ii)

(ii)
Figure for Question (ii) — AP Biology

Draw a square around the step (1, 2, 3, or 4) in the figure that illustrates an example of juxtacrine signaling.

Question 2

[Maximum number: 1]

Based on the information provided, which of the following best justifies the claim that osteocalcin is a hormone?

A

The phosphorylation of the insulin receptor causes a response in osteoblast bone cells.

B

The osteoblasts in the bone secrete osteocalcin, which causes cells in the pancreas to change their activity.

C

The change in expression of E s p changes the insulin receptor activity of the osteoblast.

D

The activation of the osteocalcin by a bone cell is pH dependent.

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