C2.1 Chemical Signaling

Question 1

Types of hormones

Answer 1

Amine, Peptide, Lipid, Steroid

Question 2

What binds intracellularly?

Answer 2

Hormones derived from steroids and lipids

Question 2

What binds extracellularly?

Answer 2

Cytokines, charged molecules (Ca2+), hormones derived from proteins & amino acids

Question 3

Cytokines

Answer 3

• small proteins involved in immune response
• secrete by white blood cells

Question 4

Calcium ions (Ca2+)

Answer 4

• released in response to external signals
• function intracellularly
• trigger cellular responses: muscle contraction

Question 5

Autocrine signaling

Answer 5

Cell secreting the signal molecule uses it for itself

Question 6

Paracrine signaling

Answer 6

Signal molecules are released to affect nearby cells

Question 7

Endocrine signalling

Answer 7

Long-distance signaling using the bloodstream

Question 8

Juxtracrine signalling

Answer 8

Signal is not released - direct cell-to-cell contact allows for contact between the ligand and receptor

Question 9

Signal transduction pathways

Answer 9

Initial signal at the cell surface is converted into a specific cellular response

Question 10

Transmembrane receptors that activate G proteins

Answer 10

1. Epinephrine binds to a GPCR
2. ATP is converted into cAMP
3. Activates protein Kinase
4. Cellular response - AMPLIFIED SIGNAL

Question 11

Tryosine Kinase activity - Insulin

Answer 11

Kinase removes phosphate group from ATP, attaching it to tyrosine, leading to conformation change -> glucose channels embedded into membrane

Question 12

Secondary messengers

Answer 12

Small molecules produced intercellularly in response to ligand binding to receptor

Question 13

Quorum sensing

Answer 13

Production of auto-inducers which move across cells and diffuse into them

Question 14

Quarum

Answer 14

Minimum amount of things needed to start a process

Question 15

Positive feedback loop - Oesterol

Answer 15

Hypothalamus secretes GnPR, which is received by puiturary gland, triggering release of LH and FSH -> act on overy, releasing oesterol, which enters the nuclei of the hypothalamus altering gene expression to release more GnPR (oesterol)

Question 16

Negative feedback loop - Testosterone

Answer 16

Hypothalamus secretes GnPR, which is received by puiturary gland, triggering release of LH -> acts on testes, releasing testosterone, which enters the nuclei of the hypothalamus and alters gene expression to release less GnPR (testosterone)