Module 3: Cell Communication And Receptor Families

Question 1

What types of diseases do you get when your nervous system breaks down?

Answer 1

MS, Parkinsons, motor neuron disease

Question 2

What types of diseases do you get when the endocrine system breaks down?

Answer 2

Diabetes, metabolic disorders

Question 3

What are the 2 broad types of cell communication?

Answer 3

1. Local communication: cell releases chemicals that react to nearby cells, e.g. immune system defence on a pathogen and synaptic.
2. Long distance communication: endocrine, home is released and travels around body and trigger response e.g. glucose released by liver and traveling around body.

Question 4

What is local communication?

Answer 4

When 1 cell releases chemicals which reacts to nearby cells to trigger a reaction

Question 5

What is long distance communication?

Answer 5

When a gland releases a hormone into the bloodstream and it travels through the body to a Receptor that needs it

Question 6

What are the 3 stages of cell to cell communication?

Answer 6

1. Reception: signaling molecule binds to a specifically shaped receptor. “Lock and key”
2. Transduction: a pathway or process happens in the cells cytoplasm
3. Response: the effect of the activation

Question 7

What are the features of reception?

Answer 7

1. Proteins respond to a specific specific molecule: ligand/agonist (hormone/neurotransmitter)
2. Receptors are on or in the cell
3. If the receptor is hydrophilic it will be on the cell to respond to phobic ligands
4. If the receptor is hydrophobic it will be inside the ans respond to phobic ligands

Question 8

What are the features of transduction?

Answer 8

1. Creates a cascade effect
2. Effect depends on the receptor

Question 9

Describe the feature of the response in cell communication

Answer 9

1. Dependent on the receptor and the cell
2. Extremely diverse.

Question 10

What are the 4 types of receptors?

Answer 10

1. Ligand gated ion channels
2. G protein coupled receptors
3. Tyrosine kinase receptors
4. Steroid receptors

Question 11

Which receptors are hydrophilic?

Answer 11

1. Ligand gated ion channels
2. G protein coupled receptors
3. Tyrosine kinase receptors

Question 12

Which receptors are hydrophobic?

Answer 12

Steroid receptors

Question 13

Which receptors respond to hormones?

Answer 13

All 4 of them
1. Ligand
2. G protein
3. Tyrosine
4. Steroid

Question 14

Which receptors respond to hormones and neurotransmitters?

Answer 14

1. Ligand gated ion receptors
2. G protein coupled receptors

Question 15

What is the reception/transduction/response flow of ligand gated ion channels?

Answer 15

Rec: hormone or NT binds
Trans: movement of ions through channel
Res: change in membrane potential (~10-100ms)

Question 16

What are the features of G protein coupled receptors?

Answer 16

1. Over 1000 types, most of them we don’t know the activation: orphan receptors
2. > 50% current drugs target them
3. Are involved in neuronal and Hormonal signaling

Question 17

What does a G protein coupled receptor look like?

Answer 17

1. Has a receptor outside of the cell
2. Has 7 transmembrane domains that the proteins flows through
3. Had the G protein inside the cell

Question 18

How does phosphorylation affect g proteins?

Answer 18

They are either turned on or off by phosphorylation or dephosphorylation.

Question 19

What does phosphorylation do?

Answer 19

Controls the activity of proteins by the use of a kinase or phosphatase enzymes

Question 20

What is a kinase?

Answer 20

An enzyme that adds a phosphate to proteins

Question 21

What is a phosphatase?

Answer 21

An enzyme that removes a phosphate from a protein

Question 22

What is the reception/transduction/response flow of adequate cyclase/protein kinase A pathway?

Answer 22

Rec: neurotransmitter or hormone bonds to G protein receptor
Trans: GDP gains a phosphate and becomes GTP which reacts to the G protein, enabling it to bind to adenylate cyclase. Adenylate cyclase converts ATP to cAMP.
Res: depending on the cell the cAMP will either
A. Opens Na+ ion channels more, creating a bigger EPSP
B. Activate protein kinase A
C. Activate gene transcription in the nucleus

Question 23

What is the G protein activation of the IP3/Protein kinase C pathway?

Answer 23

Rec: neurotransmitter binds to G protein receptor
Trans: GTP activate G protein, which activates phospholipase C, which splits PIP2 into IP3 and DAG
Res:
A. DAG activates other proteins, including Kinase C
B. IP3 triggers the release of Ca2+ into the cell.

Question 24

What is signal amplification?

Answer 24

When small quantities of signaling molecules create large effects in the cell

Question 25

What is the name of the process that creates chemical exponential growth?

Answer 25

Signal amplification

Question 26

Is the tyrosine kinase receptor involved in neuron communication?

Answer 26

No, it’s involved in neuron growth

Question 27

Is neuron growth a fast or slow process?

Answer 27

Slow process, can take days-months

Question 28

Which amino acids enable phosphorylation in tyrosine kinase receptors?

Answer 28

1. Serine
2. Threonine
3. Tyrosine

Question 29

What is the extra feature of tyrosine kinase receptors?

Answer 29

They’re also enzymes, so they can phosphorylate themselves.

Question 30

What is the reception/transduction/response flow for Tyrosine Kinase receptors

Answer 30

Rec: a hormone binds to the receptor
Trans: the 2 monomers bind to form a dimer, the active dimer phosphorylates each other using ATP to become fully active
Res:
A. Growth
B. Metabolic change
C. Transcription in the nucleus

Question 31

What is the response/transduction/response of the steroid receptors?

Answer 31

Rec: a lipophilic/hydrophobic hormone (oestrogen/testosterone) enters the cell and binds to the receptor
Trans: the receptor translocates into the nucleus
Res: activates transcription