Chapter 5

Question 1

Ligand

Answer 1

Molecules that bind to proteins reversibly

Question 2

Chemical messengers 3 Main Categories:

Answer 2

• Paracrines
• Neurotransmitters
• Hormones

Question 3

Paracrines

Answer 3

Chemicals that communicate with neighboring cells
(Simple diffusion)

• Growth Factors
• Clotting Factors
• Cytokines

Question 4

Cytokines

Answer 4

Peptides from immune cells, fight infection

Question 5

Histamine

Answer 5

Paracrine messenger, secreted by mast cells and causes inflammation

Question 6

Neurotransmitters

Answer 6

Chemicals released through axon terminals between neurons

Question 7

Presynaptic Neuron

Answer 7

Cell that releases neurotransmitter

Question 8

Post synaptic cell

Answer 8

Target cell

Question 9

Hormones

Answer 9

Messengers from endocrine glands, diffuse into blood

Question 10

Neurohormones

Answer 10

Secreted by neurons called neurosecretory cells, diffuses into blood

(Vasopressin) regulate urine

Question 11

Lipophilic (hydrophobic)

Answer 11

Lipid soluble, Cross plasma membrane can’t dissolve in plasma

Question 12

Lipophobic (Hydrophilic)

Answer 12

Dissolve in plasma, but do not cross plasma membrane

Question 13

Chemical messengers 5 major classes:

Answer 13

• Amino Acids
• Amines
• Peptides/Proteins
• Steroids
• Eicosanoids

Question 14

Amino Acid messengers

Answer 14

• Glutamate
• Aspartae
• Glycine
• Gamma-aminobutyric acid

Lipophobic, dissolve in water but do not cross plasma membranes

Question 15

Amine Messengers

Answer 15

From Amino Acids with group (-NH2) and Cateholamines

Question 16

Catecholamines (catechol group)

Answer 16

Six carbon ring, hydrophilic

• Dopamine
• Nonepinephrine
• Epinephrine

Question 17

Peptide protein Messengers

Answer 17

Amino acids linked by peptide bonds

Question 18

Peptide

Answer 18

Less than 50 amino acids

Question 19

Protein

Answer 19

Longer chains of amino acids

Question 20

Steroid Messengers

Answer 20

From cholesterol with 4 ring structure, hydrophobic

Question 21

Eicosanoid Messengers

Answer 21

Paracrines produced by almost every cell in the body, from arachidonic acid. Cross plasma membrane (hydrophobic)

• Prostaglandins- constrict blood vessels cramps
• leukotrienes-Airway contraction
• thromboxanes- platelets

Question 22

Arachidonic avid

Answer 22

20 Carbon fatty acid

Question 23

Glutamate and Aspartate synthesis

Answer 23

1) Glucose catabolized to pyruvic acid by glycolysis
2) Pyruvic acid is in turn converted to acetyl CoA, enter Kreb cycle
3) Amine groups added to keen cycle to form glutamate or aspartame

Question 24

Catecholamines (2)

Answer 24

Tyrosine beta hydroxylase
Dopa decarboxylase
Dopamine beta hydroxylase (dopamine to nonepinephrine)
PNMT (nonepinephrine to epinephrine)

Question 25

Serotonin

Answer 25

1) tryptophan 5 hydroxylase | 2) aromatic L amino acid decarboxylase

Question 26

Histamine

Answer 26

Histidine decarboxylase

Question 27

Half life

Answer 27

The amount of time it takes for half of the hormone in the blood to be degraded Proteins in carriers are protected and have longer half lives (hours)

Question 28

Affinity

Answer 28

Strength of binding between messenger and its receptor

Question 29

Magnitude of target cell’s response to Messenger factors (3):

Answer 29

1) messengers concentration 2) number or receptors 3) affinity of the receptor for messenger

Question 30

Up regulation

Answer 30

When cells have low messengers for long time, increase in number of receptors

Question 31

Down regulation

Answer 31

When high messenger conc are higher than normal for long time, causing fewer receptors to decrease responsiveness

Question 32

Receptor Agonist

Answer 32

Ligands that bind to receptors and produce response | morphine- treat pain cause euphoria band addiction

Question 33

Receptor antagonists

Answer 33

Ligands that bind to receptors that do not produce an response (naloxone- binds to morphine receptors blocks them, reversing effects) 10x affinity

Question 34

Dimerization

Answer 34

For steroid hormone to activate a gene, two complexes bind to HRE

Question 35

Lipophobic messenger receptors categories (3):

Answer 35

- Channel linked receptors - Enzyme linked receptors - G protein linked receptors

Question 36

Channel linked receptors

Answer 36

Ligand gated channel, ligand is messenger 1) fast channels- receptors and ion channels 2) slow channels

Question 37

Second messenger

Answer 37

Intracellular messenger produced by the binding of an extra cellular messenger to a receptor

Question 38

G protein linked receptors

Answer 38

Links G protein receptors and other proteins in plasma membrane called effectors Effectors- ion channels and enzymes

Question 39

G proteins function

Answer 39

Bind guanosine nucleotides - alpha 20 - beta 5 - gamma 13

Question 40

G protein classifications (3):

Answer 40

1) Affect ion channels 2) stimulatory G proteins 3) inhibitory G proteins 2 and 3 activate and inhibit amplifier enzymes

Question 41

Amplifier enzymes

Answer 41

Enzymes that catalyze the production of second messengers in intracellular fluid

Question 42

Slow ligand gated ion channels

Answer 42

Regulated by G proteins, causes channels to open or close in response to binding of alpha subunit Differences: Can be open or closed Slow to open or close (minutes instead of milliseconds)

Question 43

5 major second messengers

Answer 43

1) cAMP 2) cGMP 3) inositol triphosphate 4) diacyglycerol 5) calcium

Question 44

Phosphatidylinositol second messenger system

Answer 44

Enzyme catalyzed reaction that yield diacyglycerol (DAG) and inositol triphosphate (IP3); calcium

Question 45

Signal amplification

Answer 45

Cascades cause this by a series of sequential steps for the phosphorylation of proteins