AP®︎ Biology: Topic 4.2 Practice Test
Prepare for your quiz, test, or the AP exam with focused practice questions on Topic 4.2 of AP Biology – Introduction to Signal Transduction.
Questions List
Topic 4.2
Question 1 Easy
This question tests the following: IST-3.D.1
What is the first step in a signal transduction pathway?
What You’re Being Tested On:
Explore the learning objectives taken directly from the College Board’s AP® Biology Curriculum. Ensure you’re prepared for the exact topics covered on the AP® exam, in-class tests, and quizzes, and gain confidence in your mastery of the material.
Topic 4.2: Introduction to Signal Transduction
Learning Objective: 4.2.A
Describe the components of a signal transduction pathway.
Essential Knowledge: 4.2.A.1
Signal transduction pathways link signal receptions with cellular responses.
Essential Knowledge: 4.2.A.2
Many signal transduction pathways include protein modifications and involve phosphorylation cascades.
Learning Objective: 4.2.B
Describe the role of components of a signal transduction pathway in producing a cellular response.
Essential Knowledge: 4.2.B.1
Signaling begins with the recognition of a chemical messenger—a ligand—by a receptor protein in a target cell. i. The ligand-binding domain of a receptor recognizes a specific chemical messenger, which can be a peptide (protein) or a small molecule. ii. G protein-coupled receptors are an example of a receptor protein in eukaryotes. iii. Receptors may be located on the surface of a target cell or in the cytoplasm or nucleus of the target cell.
Essential Knowledge: 4.2.B.2
Signaling cascades relay signals from receptors to cell targets, often amplifying the incoming signals, resulting in the appropriate responses by the cell. Responses could include cell growth, secretion of molecules, or gene expression. i. After the ligand binds, the intracellular domain of a receptor protein changes shape, initiating transduction of the signal. ii. Enzymes and second messengers such as cyclic AMP (cAMP) relay and amplify the intracellular signal. iii. Hormones are an example of a signaling messenger that can travel long distances in the bloodstream. iv. The binding of ligands to ligand-gated channels can cause the channel to open or close.
