Biology · Interaction and interdependence

C2.1 — Chemical signalling

Biology · SL / HL · syllabus-mapped notes

1. C2.1.1

   Receptors as proteins with binding sites for specific signalling chemicals

   Explain receptors as proteins with ligand-binding sites, and how they differ from enzymes.

2. C2.1.2

   Cell signalling by bacteria in quorum sensing

   Explain quorum sensing, and why the activities it triggers need a crowd.

3. C2.1.3

   Hormones, neurotransmitters, cytokines and calcium ions as examples of functional categories of signalling chemicals in animals

   Describe hormones, neurotransmitters, cytokines and calcium ions as functional categories.

4. C2.1.4

   Chemical diversity of hormones and neurotransmitters

   State the two requirements of a signalling chemical, and the chemical categories of each type.

5. C2.1.5

   Localized and distant effects of signalling molecules

   Contrast localized and distant effects of signalling molecules.

6. C2.1.6

   Differences between transmembrane receptors in a plasma membrane and intracellular receptors in the cytoplasm or nucleus

   Explain why some receptors are transmembrane and others intracellular.

7. C2.1.7

   Initiation of signal transduction pathways by receptors

   Contrast signal transduction via transmembrane and via intracellular receptors.

8. C2.1.8

   Transmembrane receptors for neurotransmitters and changes to membrane potential

   Explain how neurotransmitter receptors change membrane potential.

9. C2.1.9

   Transmembrane receptors that activate G proteins

   Explain how a ligand binding a GPCR activates G protein.

10. C2.1.10

    Mechanism of action of epinephrine (adrenaline) receptors

    Explain the epinephrine pathway, and how a secondary messenger amplifies the signal.

11. C2.1.11

    Transmembrane receptors with tyrosine kinase activity

    Explain tyrosine kinase receptors using insulin and glucose transporters.

12. C2.1.12

    Intracellular receptors that affect gene expression

    Explain how steroid hormones use intracellular receptors to change gene expression.

13. C2.1.13

    Effects of the hormones oestradiol and progesterone on target cells

    Explain the effects of oestradiol and progesterone on their target cells.

14. C2.1.14

    Regulation of cell signalling pathways by positive and negative feedback

    Contrast positive and negative feedback in cell signalling, with an example of each.