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C1.1.16 (HL)—Feedback inhibition

Feedback inhibition occurs when a pathway end product inhibits an earlier enzyme, preventing excess product accumulation through negative feedback in pathways.

Syllabus
First assessment 2025
Objective
C1.1.16
Level
HL

Exam analysis

Chance of appearing9%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper1
Typical marks1–4

Common command terms

  • Explain
  • Outline
  • State

Recent exam appearances

May 2024Paper1 ["HL"] · TZ130[ 1 ]C1.1.16 (HL)—Feedback inhibition
May 2023Paper2 ["HL"] · TZ16(b)[ 4 ]C1.1.16 (HL)—Feedback inhibition
May 2023Paper1 ["HL"] · TZ128[ 1 ]C1.1.16 (HL)—Feedback inhibition
November 2021Paper1 ["HL"] · TZ029[ 1 ]C1.1.16 (HL)—Feedback inhibition
May 2019Paper2 ["HL"] · TZ15(b)[ 5 ]C1.1.16 (HL)—Feedback inhibition
Practice this objective

Coverage 2012–2024 · Updated 15 Jul 2026

Concept essentials

  • End products can inhibit enzymes near the start of a pathway.
  • Feedback inhibition is a form of negative feedback.
  • Allosteric binding changes enzyme shape and reduces pathway activity.
  • Pathway output can restart when end-product concentration falls.
ConceptIB Biology HL