Chapter 13 Flashcards
1
Q
What are the 6 enzyme classifications?
A
“Over The HILL”
Oxidoreductase
Transferase
Hydrolase
Isomerase
Lyases
Ligase
2
Q
What is the function of an oxidoreductase?
A
electron transfer (redox reactions)
3
Q
What is the function of transferase?
A
transfer of functional groups
4
Q
What is the function of hydrolase?
A
bond breakage with water
5
Q
What is the function of lyases?
A
double bond formation from group elimination
6
Q
What is the function of isomerases?
A
change isomer
7
Q
What is the function of ligase?
A
bond formation from ATP hydrolysis
8
Q
Where does glycolysis occur?
A
Cytosol
9
Q
What reactions are rate-limiting in glycolysis?
A
Reactions 1, 3, and 10
10
Q
What are the three rate-limiting enzymes of glycolysis?
A
Hexokinase
PFK
PK
11
Q
Which reactions of glycolysis produce ATP?
A
PGK (reaction 7) and PK (reaction 10)
12
Q
What are endocrine hormones?
A
Hormones released from endocrine glands into the bloodstream
13
Q
What is the function of endocrine hormones?
A
Regulate physiological processes:
Maintain homeostasis
Respond to external stimuli
Developmental programs
14
Q
What determines the specificity of signaling?
A
Presence of receptor
15
Q
What is an agonist?
A
Substances that initiate a physiological response
16
Q
What is an antagonist?
A
Substance that interferes with or inhibits the physiological action of another
17
Q
What is exocrine secretion?
A
Release of substances onto the body surface (outside body)
18
Q
Where do pancreatic secretions go?
A
Mostly digestive system (exocrine), but 1-2% are endocrine hormones
19
Q
What type of hormones does the pancreas create?
A
Polypeptide (protein) prohormones
20
Q
What organ of the endocrine system has alpha, beta, and gamma cells?
A
Pancreas
21
Q
What do alpha-pancreatic cells secrete?
A
Glucagon
22
Q
What is the purpose of glucagon?
A
Responds to low blood glucose
23
Q
What do beta-pancreatic cells secrete?
A
Insulin
24
Q
What is the purpose of insulin?
A
Responds to high blood glucose
25
What do gamma-pancreatic cells secrete?
Somatostatin
26
What is the purpose of somatostatin?
Inhibits secretion of insulin and glucagon
27
What is/are the primary targets of pancreatic hormones?
Liver, muscle, and adipose cells
28
Where are the adrenal glands located?
Above the kidneys
29
What are catecholamines?
Hormones made in the adrenal glands
30
What are the main hormones secreted by the adrenal medulla?
Norepinephrine and epinephrine
31
What are the two parts of the adrenal glands?
Cortex and medulla
32
What is the target of catecholamines?
alpha and beta-adrenergic receptors
33
What is the function of a beta-adrenergic agonist?
mimic the effect of adrenalin on beta-adrenergic receptors
34
What is the function of beta-adrenergic antagonists?
Minimize the effect of adrenaline release
35
What is the real name of beta blockers?
Beta-adrenergic antagonist
36
What drug is an example of a beta-adrenergic agonist?
Isoproterenol
37
What drug is an example of a beta-antagonist?
Propranolol
38
What drug is an example of an alpha-adrenergic antagonist?
Phentolamine
39
What is the function of glucocorticoids?
Regulate fuel metabolism, inflammatory reactions, and stress
40
What is an example of a glucocorticoid?
Cortisol
41
What is the function of mineralocorticoids?
Regulate salt and water balance
42
What is an example of a mineralocorticoid?
Aldosterone
43
What is the function of androgens?
Sexual development and function
44
What is an example of an androgen?
Testosterone
45
Where are steroid hormones produced?
Adrenal cortex, testes, and ovaries
46
What is unique about steroid hormones?
Lipid soluble; allows them to pass through the lipid bilayer and bind to cytosolic receptors
47
What do steroid hormones do upon binding to their receptor?
Move into the nucleus and act as a transcription factor
48
What is referred to as the "master gland"?
Pituitary gland
49
What is the function of hormones produced by the pituitary gland?
Regulate other endocrine glands
50
What amino acid is epinephrine and norepinephrine synthesized from?
Tyrosine
51
What is the function of adrenocorticotrophic hormone?
Signals kidney to regulate cortisol
52
What is the function of gonadotropins?
Regulate ovarian and testicular function
53
What is the function of prolactin?
Regulate mammary gland development and milk production
54
What is the function of thyroid stimulating hormone?
Regulate the amount of thyroid hormone that is being produced/released
55
What type of hormone is growth hormone?
Peptide Hormone
56
Where are the target receptors of growth hormone?
Muscle, bone, and cartilage
57
What is the difference between gigantism and acromegaly?
Gigantism is before skeletal system maturity (excess growth, but normal proportions) and acromegaly is after (excess growth of soft tissues)
58
What hormone is produced by adipose tissue?
Leptin
59
What is leptin?
Protein hormone that regulates appetite and metabolism
60
What cells does leptin act on? What does binding cause?
Hypothalamus; prevents hunger
61
What are the 3 ways the body controls enzyme activity?
Product/Substrate Availability
Allosteric Regulation
Covalent Modification
62
What are the 3 main types of covalent modification?
Glycosylation (adding carb)
Methylation (adding -CH3)
Phosphorylation (adding phosphate)
63
What amino acids are targeted by phosphorylation?
Hydroxylated amino acids
Serine, Ser, S
Threonine, Thr, T
Tyrosine, Tyr, Y
64
What type of enzyme adds a phosphate group? Removes?
Kinase: adds
Phosphatase: remove
65
What is dimerization?
Process of joining two molecular entities
66
What binds to the autophosphorylated tyrosine kinases of an RTK?
SH2 Domain
67
What does a SH3 domain bind to?
Proline-rich sequences
68
What are the steps of an RTK?
1. Ligand binding
2. Dimerization
3. Autophosphorylation
4. SH2 domain binding
3. Adaptor protein linkage to G-protein
69
What is a G-protein?
GTP Hydrolyzing protein
70
What is a GAP?
GTPase Activating Protein
71
What is a GEF?
Guanine Nucleotide Exchange Factor
72
What is an example of a GEF?
Sos
73
What are the steps of small G-protein activation?
1. Sos binding to SH3 domain of RTK
2. Sos removes GDP for Ras
3. New GTP binds to Ras
4. GTP-bound Ras is active
5. Ras activated Raf
6. Activated Raf causes MEK to be phosphorylated
7. pMEK phosphorylates MAPK
8. pMAPK moves into nucleus
9. pMAPK phosphorylates transcription factors
74
What transcription factors get activated during the MAP kinase pathway?
Fos, Jun, and Myc
75
What do Non-Receptor Tyrosine Kinases include?
Growth Hormone Receptor
Cytokine Receptor
Interferon Receptor
T Cell Receptor
Src
76
What type of protein is Src?
Myristoylated Protein
- Myristoyl is a fatty acid
- Associated with lipid bilayer
77
What are the domains of Src?
SH2
SH3
PTK (N and C lobe)
78
What is autoinhibitory of Src?
pY527
79
What is the result of pY527 in Src?
SH2 domain will bind to its own phosphotyrosine
80
What phosphorylation is required for the activity of Src?
pY416
81
What is the result of pY416 in Src?
416 phosphotyrosine will move out of binding pocket, allowing other molecules to be phosphorylated by Src's ATP
82
Where does the phosphate needed for Src activity come from?
The ATP in its own binding pocket
83
What is the function of the enzyme PTP?
Dephosphorylate tyrosine residue
84
How does PTP function?
Transfers phosphoryl group to Cys residue on enzyme and then hydrolyzes it off
85
What domain is autoinhibitory of PTP?
SH2 Domain
86
How many transmembrane domains are present in GPCR?
7
87
What is a GPCR?
G-Protein Coupled Receptor; has 3 G-Proteins in a complex (alpha, beta, and gamma)
88
What is the activity of the trimeric complex of a GPCR?
Trimeric complex is inactive
89
What is the pathway of a GPCR?
1. Ligase binding
2. Alpha subunit released
3. Exchange of GDP for GTP
4. Protein signaling (ex. adenylate cyclase)
90
What is the structure of cAMP?
3',5'-Cyclic AMP
Adenosine + Sugar w/ oxygen (from one phosphate) on carbon 3 and carbon 5
91
What is the effect of G-alpha-s?
Increase cAMP by stimulating adenylate cyclase
92
What inhibits G-alpha-s?
Cholera toxin
93
What is the effect of G-alpha-i?
Stops cellular cAMP production by inhibiting Adenylate Cyclase
94
What inhibits G-alpha-i?
Pertussis toxin
95
What is the function of cAMP phosphodiesterase?
Hydrolyzes cAMP to AMP, preventing activation of PKA
96
What drug inhibits cAMP PDE?
Sildenafil (Viagra)
97
What is Protein Kinase A?
Serine/Threonine Kinase
98
What is the function of Protein Kinase A?
Activated by 4 molecules of cAMP -> Phosphorylates Protein -> Cellular response
99
What enzyme removes phosphates from proteins?
Phosphoprotein phosphatase
100
What form is the G-alpha subunit in during the phosphoinositide pathway?
G-alpha-q
101
What occurs in the phosphoinositide pathway?
GTP-bound Gaq binds to phospholipase C and hydrolyzes PIP to DAG and IP3
102
What occurs after IP3 is produced by PLC?
1. Binds to ER calcium channel
2. Releases Ca2+
3. Ca2+ binds to calmodulin
4. Ca2+-CaM binds to CaM kinase
5. CaM kinase phosphorylates protein
6. Cellular response
103
What occurs after DAG is produced by PLC?
1. Binds to Protein Kinase C
2. PKC binds to Ca2+ through phosphatidylserine
3. PKC (bound to DAG and PS) phosphorylates a protein
4. Cellular response
104
What enzyme is used to hydrolyze IP3 to IP2?
Inositol Polyphosphate 5-phosphatase
