CourseCourseConceptConceptDocsDocuments

IB Biology HL C3.1 Integration of Body Systems Questions

Practise IB Biology HL C3.1 by tracing reflex pathways and explaining feedback control, endocrine signals, ventilation and plant responses.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • trace reflex arcs through receptors, sensory neurons, interneurons, motor neurons and effectors
  • explain feedback control of ventilation or heart rate using chemoreceptors, medulla and nerves
  • link endocrine or plant signalling examples to hormones such as auxin, oxytocin or ethylene

Covered syllabus points

C3.1.1—System integrationC3.1.2—Hierarchy in multicellular organismsC3.1.3—Integration of organsC3.1.4—Brain as information integration organC3.1.5—Spinal cordC3.1.6—Input through sensory neuronsC3.1.7—Output through motor neuronsC3.1.8—Nerves as bundlesC3.1.9—Pain reflex arcsC3.1.10—Cerebellum roleC3.1.11—Melatonin and sleepC3.1.12—Epinephrine (adrenaline)C3.1.13—Hypothalamus and pituitary controlC3.1.14—Heart rate feedback controlC3.1.15—Ventilation rate feedback controlC3.1.16—Peristalsis controlC3.1.17 (HL)—Tropic responses in seedlingsC3.1.18 (HL)—Positive phototropismC3.1.19 (HL)—PhytohormonesC3.1.20 (HL)—Auxin efflux carriersC3.1.21 (HL)—Auxin promotes cell growthC3.1.22 (HL)—Auxin and cytokinin interactionsC3.1.23 (HL)—Ethylene and fruit ripening

Question 1

[Maximum number: 1]

A computer model simulation was proposed to assess the removal of extracellular polymeric substances (EPS) from biofilms by using a detachment-promoting agent (DPA).

Simulations on a 60-day-old biofilm after 6 minutes of treatment with DPA and on the same biofilm after 84 minutes of treatment with DPA are shown as a 3D view and a cross section. Dark grey represents bacteria and light grey shows the EPS.

Figure for Question 1 — IB Biology HL

State one reason, other than the formation of an EPS, for the high resistance to antimicrobial agents in biofilm microorganisms.

Question 2

[Maximum number: 1]

Though a single nerve cell does not think, millions of them organized as a brain result in thinking. What kind of property does thinking represent?

A

Anatomical

B

Adaptive

C

Extracellular

D

Emergent

Question 3

[Maximum number: 3]

The diagram shows the liver and its main blood vessels.

Figure for Question 3 — IB Biology HL

Outline the circulation of blood through liver tissue.

All question bank results loaded