Endocrine System (Signaling)

Question 1

Ligand

Answer 1

-A chemical messenger that can bind to a specific receptor
-Two types of ligand receptors: hydrophilic and hydrophobic

Question 2

Hydrophilic ligand

Answer 2

-Transmembrane protein
-Cannot cross target cell membrane

Question 3

Hydrophobic ligand

Answer 3

-Intracellular proteins
-Can cross target cell membrane

Question 4

Receiver

Answer 4

Ligand binding receptor

Question 5

Transducer

Answer 5

Conformational change of the receptor

Question 6

Amplifier

Answer 6

Signal transduction pathway increases the number of molecules affected

Question 7

Responder

Answer 7

Something that responds to the signal

Question 8

receptor agonist

Answer 8

Activate receptor

Question 9

receptor antagonist

Answer 9

Block receptors

Question 10

Know how stimulatory vs. inhibitory signals work together to control cell signaling.

Answer 10

-Stimulatory: Activates that piece that releases the secondary messenger
-Inhibitory: Blocks the secondary releaser preventing it from being activated

Question 11

Know the difference between positive and negative feedback.

Answer 11

-Positive: Output acts as a further stimulus
-Negative: Output reduces the stimulus

Question 12

Extracellular domain of membrane-bound receptors.

Answer 12

-Receive chemical messenger (ligand)
-Changes in response to this binding

Question 13

Transmembrane domain of membrane-bound receptors.

Answer 13

-Signal transfers through this section
-Anchors into transmembrane

Question 14

Intracellular domain of membrane-bound receptors.

Answer 14

Releases secondary messengers by physical change in receptor shape

Question 15

Know what a 7-transmembrane domain receptor is and one specific example of a 7-transmembrane domain receptor.

Answer 15

-Receptor where anchor has seven cross points
-Example: G-protein-coupled receptor (GCPRs)

Question 16

Know the 4 major classes of cell surface receptors.

Answer 16

-G-protein-coupled receptors (GCPRs): We focus on this
-Ion-channel receptors
-Tyrosine kinase linked receptors
-Receptors with intrinsic enzymatic activity

Question 17

Know what G-protein-coupled receptors are.

Answer 17

-Transmembrane protein that interacts with intracellular G-proteins.
-G-proteins: Named for their ability to bind guanosine nucleotides.
-Activate second messengers.

Question 18

Be able to list and describe the steps in the G-protein cycle.

Answer 18

1.Binding of hormone induces a conformational change in receptor
2.Activated receptor binds to G alpha subunit
3.Activated receptor causes conformational change in G alpha triggering dissociation of GDP
4.Binding of GTP to G alpha triggers dissociation of G alpha both from the receptor and from G beta gamma
5.Hormones dissociates from receptor; G alpha binds to effector, activating it
6.Hydrolysis of GTP to GDP causes G alpha to dissociate from the effector and reassociate with G beta gamma.

Question 19

Know how intracellular receptors affect mRNA production.

Answer 19

-Regulate the transcription of target genes by binding to specific DNA sequences
-Increasing or decreasing mRNA production.

Question 20

Know how peptide hormones are synthesized and then made ready to exit the cell.

Answer 20

-Made in advance: Made in ER and stored in vesicles until needed
-Released through exocytosis.

Question 21

Know how steroid hormones are synthesized and then made ready to exit the cell.

Answer 21

-Synthesized on demand
-Released through diffusion.

Question 22

Characteristics of receptors for protein hormones.

Answer 22

-Utilize plasma membrane receptors
-Can not directly enter the center
-Must act through a second messenger system

Question 23

Characteristics of receptors for steroid hormones.

Answer 23

-Fast response: Membrane receptor (myometrial contraction)
-Slow response: Nuclear receptors (secretion of cervical mucus), Diffuse into cell, Attach to specific nuclear receptors, and Do NOT require a second messenger