Lecture Quiz ( Monday)

Question 1

Paracrines

Answer 1

Definition: Chemical messengers that act on neighboring cells within the same tissue.
Example: Growth factors in wound healing.

Question 2

Autocrines

Answer 2

Definition: Chemical messengers that act on the same cell that secretes them.
Example: Immune cells releasing cytokines to activate themselves.

Question 3

Neurotransmitters

Answer 3

Definition: Chemical messengers released by neurons to transmit signals across synapses.
Example: Acetylcholine, dopamine.

Question 4

Hormones

Answer 4

Definition: Chemical messengers secreted by endocrine glands into the bloodstream to target distant organs.
Example: Insulin, adrenaline.

Question 5

Amino Acid Messengers

Answer 5

Definition: Chemical messengers derived from individual amino acids.
Example: Glutamate, glycine.

Question 6

Amine Messengers

Answer 6

Definition: Chemical messengers derived from amino acids but containing an amine group.
Example: Norepinephrine, serotonin

Question 7

Peptide/Protein Messengers

Answer 7

Definition: Chains of amino acids that function as chemical messengers.
Example: Insulin, growth hormone.

Question 8

Steroid Messengers

Answer 8

Definition: Lipid-soluble chemical messengers derived from cholesterol.
Example: Testosterone, cortisol.

Question 9

Eicosanoid Messengers

Answer 9

Definition: Chemical messengers derived from fatty acids, typically involved in inflammation or immunity.
Example: Prostaglandins, leukotrienes.

Question 10

Specificity

Answer 10

Definition: The ability of a receptor to bind to a specific ligand or messenger.

Question 11

Affinity

Answer 11

Definition: The strength with which a ligand binds to its receptor.

Question 12

Saturation

Answer 12

Definition: The point at which all receptors are bound by their specific ligands.

Question 13

Up-Regulation

Answer 13

Definition: An increase in the number of receptors on the surface of a cell, making it more sensitive to a messenger.

Question 14

Channel-Linked Receptors

Answer 14

Definition: Receptors that directly open or close ion channels when bound by a ligand.

Question 15

Enzyme-Linked Receptors

Answer 15

Definition: Receptors that activate enzymes upon ligand binding, initiating intracellular signaling.

Question 16

G Protein-Linked Receptors

Answer 16

Definition: Receptors that activate G proteins, which then trigger various intracellular effects.

Question 17

Ligand-Gated Channels

Answer 17

Definition: Ion channels that open or close in response to the binding of a chemical messenger (ligand).

Question 18

Fast Ligand-Gated Channels

Answer 18

Definition: Ion channels that open or close immediately upon ligand binding

Question 19

Slow Ligand-Gated Channels

Answer 19

Definition: Ion channels that are indirectly opened by a ligand through second messengers like G proteins.

Question 20

Amplifier Enzyme

Answer 20

Definition: An enzyme activated by a receptor that amplifies the strength of a signal within the cell, such as adenylate cyclase.

Question 21

Paracrines communicate with?

Answer 21

communicate
with neighboring cells

Question 22

Neurotransmitters are released by?

Answer 22

neurons from
axon terminal

Question 23

Hormones are released from?

Answer 23

endocrine glands
(usually), diffuse into blood

Question 24

what is Lipophilic?

Answer 24

(aka: hydrophobic)
* Lipid soluble, readily cross
membrane, do not dissolve in
plasma

Question 25

what is Lipophobic?

Answer 25

(aka:hydrophilic)
* Water soluble, do not cross
membrane, dissolve in plasma

Question 26

Amino Acid Messengers

Lipophilic or Lipophobic?

Can it cross the plasma membrane?

Does it dissolve in plasma?

Answer 26

Lipophobic (Hydrophilic)

No

Yes

Question 27

Amine Messengers:

Lipophilic or Lipophobic?

Can it cross the plasma membrane?

Does it dissolve in plasma?

Answer 27

Lipophobic (Hydrophilic)

No

Yes

Question 28

Peptide/Protein Messengers:

Lipophilic or Lipophobic?

Can it cross the plasma membrane?

Does it dissolve in plasma?

Answer 28

Lipophobic (Hydrophilic)

No

Yes

Question 29

Steroid Messengers:

Lipophilic or Lipophobic?

Can it cross the plasma membrane?

Does it dissolve in plasma?

Answer 29

Lipophilic (Hydrophobic)

Yes

No

Question 30

Eicosanoid Messengers:

Lipophilic or Lipophobic?

Can it cross the plasma membrane?

Does it dissolve in plasma?

Answer 30

Lipophilic (Hydrophobic)

Yes

No

Question 31

Amino Acid Messengers

Function:
Synthesis:
Solubility:
Functional Classification:

Answer 31

Function: Neurotransmitters in brain and spinal cord

Synthesis: Must be synthesized in the neuron that secretes them

Solubility: Lipophobic (Hydrophilic)

Functional Classification: Neurotransmitters

Question 32

Amine Messengers

Function:
Synthesis:
Solubility:
Functional Classification:

Answer 32

Derived from: Amino acids
Synthesis: Most are synthesized in the secretory cell
Solubility: Lipophobic (Hydrophilic)
Functional Classification: Paracrines, Neurotransmitters, Hormones

Question 33

Peptide/Protein Messengers

Function:
Synthesis:
Solubility:
Functional Classification:

Answer 33

Most chemical messengers are: Polypeptides
Size: Contain 3-100 amino acids
Solubility: Lipophobic (Hydrophilic)
Functional Classification: Paracrines, Neurotransmitters, Hormones

Question 34

Steroid Messengers

Function:
Synthesis:
Solubility:
Functional Classification:

Answer 34

Cross plasma membrane: Yes, so cannot be stored
Synthesis: Synthesized on demand
Solubility: Lipophilic (Hydrophobic)
Functional Classification: Hormones

Question 35

Eicosanoid Messengers

Function:
Synthesis:
Solubility:
Functional Classification:

Answer 35

Produced by: Almost all cells in the body
Synthesis: Synthesized on demand
Solubility: Lipophilic (Hydrophobic)
Functional Classification: Paracrines
Additional Info: May contribute to pain/inflammatory response
Anti-inflammatory drugs: Target enzymes involved in eicosanoid synthesis (e.g. aspirin)
Aspirin: Decreases blood clotting