Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MS1 Fall > FDN Exam 2 > Flashcards

FDN Exam 2 Flashcards

Things I can't remember

1
Q

Major fatty acid we synthesize in our body?

A

Palmitic acid (16:0)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Two dietary essential fatty acids?

A
  1. Linoleic 18:2(9,12), omega 6

2. Alpha-Linolenic 18:3(9,12,15), omega 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

FA precursor of prostaglandins?

A

Arachidonic acid 20:4(5,8,11,14)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is arachidonic acid an omega-6 or omega-3 FA?

A

Omega-6!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ATP yield from one glucose molecule?

A

38 ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ATP yield from palmitate?

A

129 ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Main tissues that use FA as the primary energy source?

A

liver, heart, and skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Two bile salts that emulsify dietary fats?

A

Glycocholic and taurocholic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Primary products of lipid digestion that are absorbed (and then subsequently repackaged)?

A

Free fatty acids, 2-monoacylglycerol, cholesterol, and remaining pieces of phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Are short and medium FFA packaged into chylomicrons?

A

Nope!

Doesn’t apply to short and medium chain fatty acids. They’re so short that they are soluble in water. Absorbed across epithelial membrane directly. Excreted into blood stream directly -> albumin binds immediately. Delivers these to all the tissues. Albumin’s job is to deliver through the blood stream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What omega FA is anti-inflammatory?

A

omega 3

omega 6 are pro-inflammatory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What foods contain omega 6 PUFAs?

A

Some nuts, avocados, olives, some oils (sunflower and corn oil)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What foods contain omega 3 PUFAs?

A

plant oils (flaxseed and canola) and some nuts, certain “fatty” fish (tuna, salmon, herring, etc)

Ex: DHA and EPA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

FA Synthesis building blocks and enzyme?

A

One acetyl CoA + multiple malonyl CoAs

Fatty Acid Synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does Acetyl CoA get from the mitochondria to the cytoplasm for FA synthesis?

A

The citrate-oxaloacetate shuttle

Citrate synthase in mitochondria and then ATP citrate lyase in the cytoplasm

Oxaloacetate diffuses back into mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Enzyme that converts acetyl CoA to Malonyl CoA in the cytoplasm? What inhibits and stimulates that enzyme?

A

Acetyl CoA Carboxylase (ACC)

Stimulates: citrate (we have energy. let’s make fat storage!)
Inhibits: Palmitoyl CoA and PKA (breaking down fats, stop making storage!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Do we store fat in the liver?

A

Nope. If we do then there is an issue (like alcoholic fatty liver disease!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What activates hormone sensitive lipase (HSL) in adipose tissue?

A

Epinephrine or glucagon

Signal cascade from GPCR -> -> -> PKA -> HSL activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What inhibits hormone sensitive lipase?

A

Insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do fatty acids get from the cytoplasm to the mitochondria to undergo beta oxidation?

A

the acyl-carnitine/carnitine transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is cholesterol a precursor for?

A

Bile acids, steroid hormones, and vitamin D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the only method of cholesterol removal from the body?

A

Bile secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What makes up the hepatic pool of cholesterol?

A
  1. diet (chylomicrons)
  2. Hepatic synthesis
  3. Other tissues (HDL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What tissues synthesize cholesterol?

A

Virtually all of them

Highest rates in the liver, intestines, adrenal cortex, and reproductive tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Primary enzyme responsible for the production of cholesterol?

A

HMG CoA Reductase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

FA synthesis occurs where?

A

Primarily cytoplasm of hepatocytes

Some in adiposes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

FA breakdown/B-oxidation primarily occurs where?

A

Mitochondria of all cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Four plasma lipoprotein particles?

A
  1. chylomicrons
  2. VLDL
  3. LDL
  4. HDL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What apolipoprotein is unique to chylomicrons?

A

B-48

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What apolipoproteins does a “nascent” chylomicron pick up in order to make it “mature”?

A

Apo E and Apo C-II from HDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What apolipoprotein interacts with lipoprotein lipase (LPL) in tissue capillaries? Explain what this interaction does.

A

Apo C-II activates LPL to degrade the chylomicron TAG to fatty acids and gylcerol

When ~90% of TAG is removed, Apo C-II returns to HDL. Now we have a “chylomicron remnant” with Apo B-48 and Apo E

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What apolipoprotein allows liver cells to recognize chylomicron remnants and take them up?

A

Apo E

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Where is lipoprotein lipase (LPL) highest?

A

heart tissue to provide adequate FA for energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Describe insulin’s effects on muscle LPL and adipose LPL after a meal

A

Muscle: inhibits LPL. If glucose is high skeletal muscle would rather use that.

Adipose: stimulates LPL so the adipose tissue can store.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What apolipoprotein is unique to VLDL?

A

Apo B-100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What apolipoproteins does a “nascent” VLDL particle pick up in order to make it “mature”?

A

Apo C-II and Apo E from HDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What apolipoproteins does a TAG-depleted VLDL have?

A

Just Apo B-100

Apo E and Apo C-II return to HDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What causes a VLDL to become LDL?

A

TAG loss and protein changes (loses apo E and apo C II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Where is VLDL produced?

A

In the liver! Contains TAG and cholesterol/cholesteryl esters (CE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Job of LDL?

A

Delivers cholesterol to all other tissues; they have apo B-100 receptors that endocytose the LDL particle

Also delivers LDL particles to the liver. Because if we have excess LDL particles then we want the liver to remove them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What percentage of total plasma cholesterol is in LDL particles?

A

70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What protein is responsible for LDL receptor degradation?

A

PCSK9

Brings the receptors to a lysosome to die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Besides hypercholesteremia type IIa, what other mechanisms can cause hypercholesteremia?

A
  1. Defects in apo B-100. We have a perfectly good LDL receptor but it cannot recognize a defective apo B-100
  2. Increased activity of PCSK9. We degrade too many LDL receptors/don’t recycle enough

Both result in blocked LDL clearance in the liver/increased LDL in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

When a lipid or apo B has been oxidized, what receptor interacts with it & takes it up?

A

Scavenger receptor (SR-A) on macrophages

There is no down-regulation of this receptor by cholesterol, so high levels accumulate in the macrophage transforming it to a foam cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the primary cause of atherosclerosis?

A

Excess LDL-derived cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is HDL’s job?

A

Take excess cholesterol from extra hepatic tissues and bring it back to the liver.

This is called “reverse cholesterol transport (RCT)”

Note: inverse relationship between plasma HDL levels and atherosclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What can raise HDL levels?

A

Estrogen and exercise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How is cholesterol exported from cells into plasma?

A

Via the ABCA1 transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How does a nascent HDL particle (HDL3) become HDL2?

A

The plasma-facing enzyme LCAT (lecithin:cholesterol acyltransferase) is bound to HDL and esterifies free plasma cholesterol. This allows HDL3 to become cholesteryl ester rich and thus HDL2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How is HDL2 taken up by the liver?

A

Endocytosis

It’s contents are released into the hepatic cholesterol pool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Where are nascent HDL particles made?

A

the liver and the small intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

How does excess cholesterol impact gene expression?

A
  1. Inhibits expression of HMG CoA reductase gene slowing synthesis
  2. Inhibits expressions of the LDL receptor gene limiting further entry of cholesterol into cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What does the cell do with excess cholesterol?

A

Esterifies it via acyl CoA:cholesterol acyltransferase (ACAT). The cholesterol esters are stored in the cell.

ACAT is allosterically stimulated by excess cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How much can diet changes decrease your cholesterol?

A

Modestly. Only 10-20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How much can statin drugs decrease your cholesterol?

A

By 30-60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Four treatments for elevated cholesterol

A
  1. Statins (inhibit HMG CoA Reductase)
  2. Bile acid binding resins (increase conversion of cholesterol to bile acids)
  3. PCSK9 Inhibitors (increase LDL receptor recycling)
  4. Cholesterol absorption inhibitors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Plasmalogens

A

Phospholipids that have a long-chain hydrocarbon at carbon 1 via an ether linkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Sphingolipids

A

Have a sphingosine backbone instead of glycerol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Sphingomyelin

A

Sphingolipid with phosphocholine at carbon 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Cerbrosides, globosides, and gangliosides are what?

A

Glycolipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What determines blood groups?

A

Glycosphingolipids

We have antibodies opposite to the antigen/glycosphingolpid that we have. i.e. Type A has anti-B antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Prostaglandins, leukotriences, and thromboxanes are what?

A

Lipid-derived signaling molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Where is arachidonic acid released from?

A

Membrane localized phosphotidylinositol (PI) by phospholipase A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What do aspirin and ibuprofen inhibit?

A

Cox1/2 enzymes and the conversion of arachidonic acid into prostaglandins and thromboxanes (inflammatory responses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What does Celebrex inhibit?

A

Cox 2 pathway specifically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is a vitamin?

A

An essential micronutrient that we cannot synthesize in sufficient amounts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the fat soluble vitamins?

A

A, D, E, K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Vitamin A

A

Retinoid family of molecules. Essential for vision, reproduction, growth, maintenance of epithelial tissue, and immune function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Retinol

A

Dietary vitamin A found in animal tissues (storage form)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

11-cis retinal

A

Critical for vision. Aldehyde of retinol

Deficiency results in night blindness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Retinoic acid

A

Used to treat acne and skin aging as well as promyelocytic leukemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is active vitamin D? How is it generated?

A

1,25-dihydroxycholecalciferol

Conversion from 7-dehydrocholesterol via UV irradiation

Or activation of inactive dietary precursors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What does vitamin D control?

A

Serum calcium and phosphate levels via transcription

It’s a sterol with a hormone-like function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Dietary sources of vitamin D?

A

Fatty fish, liver, egg yolk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Vitamin K

A

required for the synthesis of proteins involved in blood clotting

A deficiency is rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Vitamin E

A

Functions as an antioxidant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Vitamin E is used to slow the progress of what age-related vision condition?

A

Macular degeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Vitamin E deficiency in adults usually results from

A

Abetalipoproteinemia - defective formation of chylomicrons and VLDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Where does synthesis of steroid hormones occur?

A

Adrenal cortex, ovaries/placenta, and testes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

How are steroid hormones excreted once they’re turned over?

A

They are converted to inactive, water-soluble products in the liver and eliminated in feces and urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Where are cortisol, aldosterone, and androgens made?

A

In the adrenal cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Cortisol function

A

Synthesis is increased by stress. Functions to increase protein turnover (makes AAs for gluconeogenesis) and decreases inflammatory and immune responses

Glucocorticoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Aldosterone function

A

Acts on the kidneys to increase Na+ and water resorption and to increase K+ excretion

Produced in response to a decrease in the plasma Na+/K+ ratio and by the hormone angiotensin II

Increases BP!

Mineralcorticoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Androgens

A

Weak androgens are made in the adrenal cortex and converted by the enzyme aromatase to testosterone in the testes and to estrogens in the ovaries (pre-menopausal women) and in the breast (post-menopausal women)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Estrogen controls what?

A

Menstrual cycle & secondary female sex characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Progesterone controls what?

A

Secretory functions of uterus and mammary tissue + implantation/maturation of ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Three ketone bodies?

A

Acetoacetate, beta-hydroxybutyrate, and acetone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Can the liver use ketone bodies as fuel?

A

No. It lacks thiophorase, the enzyme needed to convert ketone bodies back to acetyl CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Is DKA seen most-often in Type 1 or Type 2?

A

Type 1

Ref: Kilberg’s Lipid Homeostasis lecture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Fuel source and priority during phase 1 of fasting?

A

Source: glycogen/glucose

Priority: Blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

Fuel source and priority during phase 2 of fasting?

A

Source: Proteins/AA

Priority: Blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

Fuel source and priority during phase 3 of fasting?

A

Source: Lipids/ketone bodies

Priority: Avoiding death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Is adipose tissue involved in phase 1 of fasting?

A

Nope!

It mobilizes in phase 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What is the glucose-alanine cycle? When does it occur?

A

It happens during the first phase of fasting. Slowly mobilizing proteins

Similar to the Cori Cycle. Pyruvate is transaminated in the muscles to alanine. In the liver alanine is de-aminated (NH to Urea cycle) back to pyruvate and that pyruvate goes into gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

Where is the #1 place people are protein deprived?

A

The hospital

Know this!! He does research in this!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

Is insulin still available during phase 3 starvation?

A

Yes, but very very little

Remember: glucagon stimulates a little insulin release to keep itself in check

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

How many calories is in one pound of fat?

A

3500

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

Why isn’t injected insulin as good as the real thing?

A

Because in the islets, insulin flows outward toward the beta cells. Insulin inhibits glucagon release, stopping glucagonemia. Unchecked type 1 diabetes is absolute glucagonemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

Who enters a coma first: a diabetic patient or a fasting patient?

A

A diabetic

A fasting patient has some insulin to keep things in check. The diabetic does not so everything runs rampant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

Conformations of transporter?

A

Open, closed, inactivated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

Properties of channels

A
  • Fast transport of ions across membrane
  • Move ions down their conformation gradient
  • Can be ligand, voltage, or mechanically gated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

Conformations of a uniporter/transporter?

A

Outward-facing, inward-facing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

Properties of uniporters/transporters

A
  • 1 molecule transported per confirmation change
  • Medium rate
  • Passive movement down concentration gradient
  • Can switch directions depending on the gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

Properties of active transporters/pumps

A
  • Conformational change linked to ATP hydrolysis
  • Slow rate
  • Against concentration gradient
  • 1 to several molecules per conformation change cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

Secondary active transport

A

Movement of an ion down its concentration gradient coupled to transport of ion/molecule against concentration gradient

Symporter or antiporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

Where are GLUT4 transporters found?

A

Skeletal muscle, adipocytes, and the heart

Insulin responsive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

Where are SGLT1 transporters found?

A

Intestines, distal renal tubules

High affinity, low capacity for glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

Where are SGLT2 transporters found?

A

Proximal renal tubules

Low affinity, high capacity for glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

In the Na+/glucose symporter how many of each molecule move inside the cell?

A

2 Na+, 1 glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

SGLT2 Inhibitors

A

Block SGLT2 in the renal proximal tubules. SGLT2 reabsorbs ~90% of glucose in PCT. Inhibition results in glycosuria and lower blood glucose levels -> great for treating hyperglycemia found in diabetes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

What is the most abundant transmembrane protein in RBC plasma membrane?

A

AE1. Anion exchange 1 - antiport of chloride and bicarbonate anions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

Chloride shift

A

In systemic capillaries, HCO3- is transported out of RBC and Cl- is transported in to balance the negative charge

113
Q

How is CO2 transported in plasma?

A

As HCO3-

114
Q

Two antiporters used to raise intracellular pH?

A
  1. Na+/H+ Exports H+ from cells (gets rid of the proton)

2. Na+HCO3-/Cl- imports Na+HCO3- into the cell (brings in a base)

115
Q

One antiporter used to lower intracellular pH?

A

Cl-/HCO3- Exports HCO3- from the cell (gets rid of a base)

116
Q

What mediates channel selectivity?

A

Ion size and interactions with the selectivity filter (amino acids in the pore)

Those ions meant for the channel have a low activation energy. Those ions not meant for the channel have a very high activation energy

117
Q

Are channels opened or closed in their resting state?

A

Either!

118
Q

What is the rate-limiting step in transporters and pumps?

A

The conformational change

119
Q

Do channel conformational changes regulate state or rate?

A

State

There is no rate-limiting step in channel transport

120
Q

Where is aquaporin 1 located?

A

RBCs

Mediates rapid osmotic water flow

121
Q

Where is aquaporin 2 located?

A

Kidney collecting duct

Regulates urine osmolality

122
Q

What prevents proton hopping in aquaporins?

A

Water molecules are transported single file

123
Q

Properties of membrane pumps

A
  • Energy source is ATP hydrolysis
  • Transport against a gradient
  • One direction
  • Speed is slower than transporters and channels
124
Q

Three types of ATP-powered pumps?

A
  1. P-type
  2. F and types
  3. ABC transporters
125
Q

Properties of P-Type Pumps

A
  • Only pumps ions
  • Alpha and beta subunits
  • Alpha subunit is phosphorylated, inducing a conformational change (E1/E2 conformations)

Examples: Na+/K+ pump, Ca2+ pump in plasma membranes and sarcoplastic reticulum (SERCA!)

126
Q

Describe E1/E2 conformations in SECRA Ca2+ ATP pump

A

E1 is inside-facing/cytosol facing. Has a high affinity for Ca (so it can collect it)

E2 is outward-facing/lumen facing. Has a low affinity for Ca (so it gets released)

Phosphorylation favors E2. De-phosphorylation favors E1.

(Same mechanism in Na+/K+ pump)

127
Q

Properties of F-type pumps

A
  • Only pumps protons!!
  • Synthesizes ATP
  • Has catalytic F1 sector
  • F0 is multiple transmembrane subunits
  • NO subunits phosphorylated

Example: inner mitochondrial membrane (ATP synthase)

128
Q

Properties of V-type pumps

A
  • Only pumps protons!!
  • used to acidify compartments of the cell (i.e. the lysosome)
  • Has catalytic V1 sector
  • V0 is multiple transmembrane subunits
  • NO subunits phosphorylated

Example: osteoclast plasma membrane V-type ATPase secretes HCl into absorption lacuna

129
Q

Properties of ABC Transporter superfamily

A
  • Transport ions, sugars, amino acids, lipids, and peptides
  • Very diverse; not homogenous like P, F, and V type pumps (not even all pumps!!)
  • Contains four domains (2 A and 2 T) or as 1 multidomain protein
  • NO subunit phosphorylation during the transport cycle

Example: Multidrug resistance transporter, CFTR

130
Q

What is the most common MDR transporter?

A

permeability glycoprotein (P-gp)

131
Q

How is the Cl- channel activated in CFTR?

A

Phosphorylation of R domain (regulatory domain) and ATP hydrolysis by the nucleotide binding domains (NBD1 and 2)

132
Q

What two things does cholera toxin ultimately cause in the intestinal cells?

A
  1. Efflux of Cl- ions and flow of water across epithelium into lumen
  2. Inhibition of Na+ and Cl- absorption (by Na+/H+ anion exchanger)
133
Q

How does rehydration therapy work during cholera?

A

Since cholera toxin doesn’t effect the Na+/glucose symporter, rehydration therapy are solutions containing salts and glucose. Water will follow glucose back into the cells

134
Q

Resting membrane potential is due primarily to what?

A

K+ leak channels

135
Q

When K+ electrochemical gradient = 0, what is the resting membrane potential?

A

-59 mV

136
Q

Describe beta cell insulin secretion

A
  • Glucose enters the cell and undergoes glycolysis then TCA cycle & oxphos to make ATP
  • Increase in ATP in cytoplasm closes ATP-gated K+ channel
  • This closure triggers a membrane depolarization sensed by a voltage-gated Ca2+ channel
  • This channel opens and Ca2+ flows in
  • Cytosolic Ca2+ induces fusion of secretory vesicles with plasma membrane
137
Q

Requirement for action potentials?

A

Resting plasma membrane potential in an excitable cell

138
Q

What ensures unidirectional action potential propagation?

A

Na+ channel inactivation

139
Q

What is the clinical presentation of hypoglycemia?

A

Adrenergic symptoms and neuroglycopenia

140
Q

What is “adrenergic symptoms”?

A

Systemic effects of catecholamines (adrenaline) from the adrenal medulla

Examples: tachycardia, sweating, palpitations, anxiety, feeling cold, sweating

141
Q

What is neuroglycopenia?

A

The consequences of low blood glucose on CNS function

Examples: decreased consciousness, faintness, slurred speech, hunger, incoordination, dizziness, confusion

142
Q

Paresthesias

A

pins and needles feeling

symptom of neuroglycopenia

143
Q

What is Whipple’s Triad?

A

The clinical diagnosis of hypoglycemia. Must have low blood glucose (< 45mg/dL), symptoms of hypoglycemia, and have a positive response to glucose administration

144
Q

How is hyperinsulinemic hypoglycemia defined?

A

Increased insulin above reference interval

OR

Insulin/glucose ratio is inappropriately elevated (> .30)

145
Q

What drugs release insulin from the pancreas?

A

Sulfonylurea class (glipizide, glyburide, and glimepiride) or meglitinides

Both of these are used to treat type 2 diabetes

146
Q

What non-diabetes drugs can cause hypoglycemia?

A

Aspirin poisoning, acetaminophen poisoning, and ethanol

147
Q

What is in the differential diagnosis of non-hyperinsulinemic hypoglycemia?

A

Drugs (alcohol, aspirin, tylenol), hormone deficiencies, liver and renal diseases, inborn errors of metabolism

148
Q

Insufficiencies in what four hormones can cause hypoglycemia?

A

Glucagon, epinephrine, cortisol, and growth hormone

149
Q

Would we expect to see ketones in the urine during hypoglycemia?

A

Yes

150
Q

How does ethanol consumption lead to hypoglycemia?

A

Conversion of ethanol to aldehyde then ethanoic acid requires NAD+. Conversion of lactate to pyruvate (necessary step in the Cori cycle to regenerate glucose) also requires NAD+. Theoretically we will deplete the NAD+ stores and not be able to generate pyruvate and run gluconeogenesis

151
Q

What is the first diagnostic test when evaluating hypogylcemia?

A

If it is hyperinsulinemic or non-hyperinsulinemic

152
Q

What lab results are typically observed in hyperinsulinism?

A

Urine negative for ketones, BHB not elevated and may be suppressed, normal FFA concentrations

These reflect the suppressive effect of hyperinsulinism on the generation of alternative fuels

153
Q

What should be considered if a patient has biochemical findings compatible with hyperinsulinism but their insulin is actually suppressed?

A

Mesothelial tumor that secrete IGF-II

Remember: biochemical findings of hyperinsulinism are normal BHB, no urine ketones, and normal levels of branched amino acids & FFA

154
Q

On average, what percentage of total body weight is water (in adults)?

A

60%

Just know that its higher in babies and lower in old people

155
Q

What is the distribution of water in extra vs. intracellular spaces?

A

2/3 in intracellular

1/3 extracellular

156
Q

How is extracellular water distributed?

A

75% interstitial space

25% plasma

~0% negligible in transcellular fluids like CSF, joint fluid, cavities, etc

157
Q

What is usual blood volume?

A

85 mL/kg

158
Q

How do you calculate hematocrit?

A

RBC volume (or mass)/blood volume

159
Q

How can you measure a fluid volume?

A

Add a known amount of dye to a volume to be measured and then measure the dye concentration

Volume = Mass added / (Mass/Volume [Concentration)] —> Mass * (Volume/Mass) = Volume

** dye must be contained within the measured compartment

160
Q

What electrolytes and proteins are high intracellularly?

A

K+, Mg2+, PO4—, protein (neg charge)

161
Q

What electrolytes and proteins are low intracellularly?

A

Na+, Ca2+, HCO3-

162
Q

What electrolytes and proteins are high extracellularly?

A

Na+, Ca2+, HCO3-, Cl- (slave to Na+)

163
Q

What electrolytes and proteins are low extracellularly?

A

K+, Mg2+, protein

164
Q

Where is protein level greater: plasma or interstitum?

A

Plasma

Remember: liver secretes albumin directly into plasma

Since proteins have a slight negative charge there will be more cations (re: Na+) in the plasma vs. interstitium

165
Q

What regulates the distribution of water between the intracellular and extracellular spaces?

A

Osmolality

166
Q

What is osmolality?

A

Particle # per kg fluid weight

167
Q

How can plasma molality be estimated?

A

(Na+ x 2) + (glucose/18) + (BUN/2.8)

168
Q

What is a normal plasma osmolality range?

A

275 - 295 mOsm

169
Q

What regulates the distribution of fluids between the interstitial space and the plasma?

A

Hydrostatic pressure, oncotic pressure, and lymphatic function

170
Q

70-75% of oncotic pressure is due to what?

A

albumin concentration

171
Q

How is O2 delivery to tissues measured?

A

cardiac output * O2 content of the blood

172
Q

What is the formula for minute volume?

A

MV = Respiratory rate * tidal volume

173
Q

pCO2 and minute volume have what kind of relationship?

A

Inverse

174
Q

In chronic respiratory acidosis why is HCO3- typically elevated?

A

The kidney retains Na+ HCO3- as renal compensation

Note: this takes days to weeks, which is why this is in CHRONIC respiratory acidosis

175
Q

Sensible vs. insensible losses

A

Sensible losses can measure the fluid lost

Insensible losses cannot be readily measured

176
Q

What is the general, basal fluid requirement?

A

1500 mL/M^2 per day

177
Q

What are the basal fluid losses?

A

Urine: 900 mL/M^2
Stool: 100 mL/M^2
Insensible loss: 500 mL/M^2

178
Q

How do you calculate fluid requirements based on body weight?

A

1-10 kg (1st 10 kg) is 100mL/kg

11-20 kg (2nd 10 kg) is 50 mL/kg

20 and higher is 20 mL/kg

179
Q

What does effective serum osmolality exclude?

A

Urea

Because urea freely crosses cell membranes and does not cause water shifts

180
Q

How is a hyperglycemic hyperosmolalic state characterized?

A

Significant hyperglycemia, some degree of mental status changes, and usually little or no acidosis or ketosis

181
Q

How many cm in an inch?

A

2.54 cm per inch

182
Q

How many lbs in a kg?

A

2.2lbs per kg

183
Q

How do you calculate BMI?

A

kg/M^2

184
Q

What amino acid can be transaminated to pyruvate?

A

alanine

185
Q

What amino acid can be transaminated to a-ketoglutarate?

A

glutamate

186
Q

What amino acid can be transaminated to oxaloacetate?

A

aspartate

187
Q

Three sources of amino acids?

A
  1. Digestion of protein in food
  2. Intracellular proteolysis
  3. de novo synthesis
188
Q

Nutritionally essential amino acids?

A

HV MILK FTW

(High Value MILK, “for the win”)

Histidine
Valine

Methionine
Isoleucine
Leucine
Lysine (K)

Phenylalanine (F)
Threonine
Tryptophan (W)

189
Q

Conditionally essential amino acids?

A

Arginine (for growth in childhood and pregnancy)

Tyrosine (when phenylalanine is inadequate)

Cysteine (when methionine is inadequate)

190
Q

What does the intracellular protein turnover rate depend on?

A

metabolic state.

Ex: Greater protein degradation when nitrogen intake is low

191
Q

Two major pathways for intracellular protein turnover?

A
  1. Lysosomal/phagolysosomal pathway (isoelectric expansion and proteolysis)
  2. Ubiquitin-dependent pathway (tagged proteins are brought to the proteasome)
192
Q

When do we need a positive nitrogen balance?

A

During periods of growth (childhood, pregnancy), in healing of wounds, and convalescence

193
Q

Marasmus is due to inadequate intake of what?

A

Calories. Extensive tissue and muscle wasting is seen

194
Q

Kwashiorkor is due to inadequate intake of what?

A

Protein! Otherwise adequate caloric intake

195
Q

Transaminases use what as a coenzyme?

A

Vitamin B6

PLP - pyridoxal phosphate
PMP - pyridoxamine phosphate

196
Q

What is the Keq of transamination reactions?

A

1

We have the same bonding in substrates and products

197
Q

What is the transamination reaction that turns alanine into pyruvate?

A

Alanine + a-ketoglutarate —> glutamate + pyruvate

198
Q

What is the transamination reaction that turns oxaloacetate into aspartate?

A

Glutamate + oxaloacetate –> a-ketoglutarate + aspartate

199
Q

What does glutamate dehydrogenase do? Where does it function?

A

It is the major route for oxidative deamination. Takes glutamate + H2O + NAD+ and makes a-ketoglutarate + NH3 + NADH

GDH is located in the mitochondrial matrix

200
Q

What can be coupled with transaminases to allow the oxidative degradation of 14 amino acids?

A

glutamate dehydrogenase

  • NADH goes to OxPhos
  • a-KA enters the TCA cycle
  • Excess NH4 goes to the Urea Cycle
201
Q

What two substrates determine the direction of GDH?

A

NAD+ and NADPH

NAD+ : oxidative deamination route

NADPH: reductive amination route

202
Q

Three routes for deamination?

A
  1. Glutamate dehydrogenase
  2. Glutaminase (glutamine to glutamate + NH3)
  3. Asparaginase (asparagine to aspartate + NH3)
203
Q

What is the main way the body traps NH3?

A

In glutamine via glutamine synthetase (glutamate + NH3 = glutamine)

Glutamine is the major nitrogen shuttle between organs, avoiding the direct transfer of NH3

204
Q

Where is the main site of NH3 detoxification in the body?

A

The liver

205
Q

Where in the cell does the Urea cycle take place?

A

Partially in the mitochondria and the cytoplasm (citrulline is shuttled out of the mitochondria and then ornithine back in)

206
Q

What stimulates the biosynthesis of all five urea cycle enzymes after a meal?

A

Glucagon

This make sense because glucagon wants gluconeogenesis to run and we need a-ketoacids to make this happen. The urea cycle makes a-ketoacids

207
Q

What two amino acids are also powerful regulators of the urea cycle?

A

Arginine and glutamate

208
Q

What amino acids cannot have their transamination coupled with GDH?

A

Proline, hydroxyproline, threonine, lysine, and histidine

209
Q

A deficiency in n-acetyl-glutamate synthetase results in what?

A

hyperammonemia (we can’t excrete excess NH3 through the urea cycle)

210
Q

What are the primary and secondary deficiencies in NAGS?

A

Primary: mutation in the NAGS gene

Secondary: mitochondrial changes interfering with NAGS function

211
Q

What molecule can restore or improve Urea cycle function in the presence of a NAGS deficiency?

A

Carbamoylglutamate

212
Q

What prevents ammonia re-entry into circulation in the liver?

A

the acinus

213
Q

The periportal hepatocytes have a high/low affinity for NH3?

What enzyme(s) take up NH3 in this area?

A

low affinity/high clearing of NH3

Glutaminase and the urea cycle enzymes take up NH3

214
Q

The perivenous scavenger cells have a high/low affinity for NH3?

What enzyme(s) take up NH3 in this area?

A

High affinity/low clearing

Glutamine synthetase takes up NH3 here. Remember that Gln Syn. uses ATP so it’s not going to be clearing a ton of NH3 like the periportal hepatocytes

215
Q

What amino acid is the source of creatine?

A

arginine

216
Q

What is the “ATP buffer” in muscle?

A

Creatine-P

217
Q

What is the breakdown product of creatine-P in our muscles?

A

Creatinine

Clearance rate of creatinine tells us how well the kidneys are working

218
Q

Three ways that glutamate can be made?

A
  1. Transamination with a-KG
  2. Reductive amination via GDH
  3. Hydrolysis of glutamine
219
Q

How is glutamine made?

A

Exclusively by glutamine synthetase

220
Q

Two ways aspartate is made?

A
  1. Transamination of oxaloacetate

2. Hydrolysis of asparagine

221
Q

What two amino acids are required to make asparagine?

A

Aspartate and glutamine

222
Q

The production of asparagine also produces what other amino acid?

A

Glutamate

223
Q

How is alanine formed?

A

Transamination of pyruvate only

** useful in the alanine/pyruvate shuttle in clearing NH3 from tissues

224
Q

What amino acid is necessary for the production of proline?

A

Glutamate

It’s reduced first to glutamate semi-aldehyde and then a cyclic compound is formed & reduced to make proline

225
Q

Glutamate semi-aldehyde can be transaminated to what urea cycle intermediate?

A

L-ornithine

226
Q

What role does vitamin C play in the production of hydroxyproline?

A

It restores the functionality of the prolyl hydroxylase enzyme by converting Fe(III) to Fe(II)

227
Q

Precursor molecule of serine?

A

3-phosphoglycerate

228
Q

How many ways can glycine be made?

What two other amino acids are glycine precursors?

A

4

Glutamate and Serine

229
Q

Tyrosine is made from what amino acid precursor?

A

Phenylalanine

230
Q

In what three ways do humans get nucleotides?

A
  1. Dietary intake of RNA and DNA
  2. Salvage of bases (reuse reduces need for additional foodstuffs)
  3. de novo synthesis
231
Q

What enzyme is responsible for the reaction that takes dUMP and Methylene-THF and makes dTMP?

A

Thymidylate Synthase

232
Q

What molecule stops thymidylate synthase in a suicide inhibition mechanism?

A

Flurouracil

233
Q

What two drugs inhibit folate reductase and dihydrofolate reductase?

A

Methotrexate and Aminopterin

234
Q

What energy source is needed for the conversion of IMP to AMP?

A

GTP

235
Q

What energy source is needed for the conversion of IMP to GMP?

A

ATP

236
Q

What amino acid is needed for the conversion of IMP to AMP?

A

Aspartate

237
Q

What amino acid is needed for the conversion of IMP to GMP?

A

glutamine

238
Q

Excess levels of AMP inhibit the production of what two products in purine nucleotide synthesis?

A

AMP and PRPP

239
Q

Excess levels of GMP inhibit the production of what two products in purine nucleotide synthesis?

A

GMP and PRPP

240
Q

Excess levels of IMP inhibit the production of what product in purine nucleotide synthesis?

A

5’-P-Rib-NH2

241
Q

What enzyme does high levels of AMP activate (ultimately turning off purine pathway enzymes)?

A

AMP-Protein Kinase

242
Q

Enzyme responsible for AMP to ADP rxn?

A

Adenylate Kinase

243
Q

Enzyme responsible for GMP to GDP rxn?

A

GMP kinase

244
Q

Enzyme responsible for ADP to ATP rxn?

A

Trick question! It’s oxidative phosphorylation

245
Q

Enzyme responsible for GDP to GTP rxn?

A

Nucleoside Diphosphate Kinase

246
Q

What enzyme converts AMP back to IMP?

A

AMP deaminase

247
Q

What enzyme converts GMP back to IMP?

A

GMP reductase

248
Q

What enzyme salvages hypoxanthine and guanine from degradation?

A

hyoxanthine:guanine phosphoribosyl transferase (HGPRT)

249
Q

Is adenine salvaged by HGPRT?

A

Nope

250
Q

What enzyme converts adenine to hypoxanthine?

A

Adenine deaminase

251
Q

List the steps from GMP to Xanthine

A

GMP
Guanosine
Guanine
Xanthine

Then Uric Acid!

252
Q

List the steps from AMP to Xanthine

A 
AMP
IMP
Inosine
Hypoxanthine
Xanthine

Then Uric Acid!

253
Q

Ribonucleotide Reductase

A

Enzyme responsible for making 2’-deoxyribonucleotides needed for DNA synthesis

Indirect electron transfer from NADPH ultimately reduces RNR

254
Q

Substrates for RNR in eukaryotes?

A

ADP, GDP, CDP, AND UDP

NO TDP! We get dTMP via thymidylate synthase

This substrate specificity gives evidence of transition from RNA to DNA world

255
Q

How is RNR regulated?

A

RNR catalysis is controlled by allosteric specificity sites

This allows RNR to sense the relative abundance of NDPs, to make the right amount of each, and to prevent overproduction of any single dNTP

256
Q

What do you need to make hemoglobin?

A
  1. Hb alpha and beta chains
  2. Porphyrin (protoporphyrin IX)
  3. iron
257
Q

What is the differential diagnosis of a microcytic anemia?

A

Defects in hemoglobin synthesis

  • Hb chain imbalance (thalassemia)
  • Impaired porphyrin synthesis (lead ingestion or sideroblastic anemia)
  • Iron deficiency or lack of iron availability
258
Q

What does sideroblastic anemia do to Hb synthesis?

A

It impairs porphyrin synthesis

259
Q

What is thalassemia?

A

Defect in hemoglobin chain synthesis (there is an imbalance)

260
Q

Hemoptysis

A

coughing up blood

261
Q

Hematemesis

A

vomiting blood

262
Q

Hematochezia

A

fresh blood per rectum

263
Q

Melena

A

black stools because of bleeding

264
Q

Hematuria

A

blood in urine

265
Q

Menorrhagia

A

excessive menstrual bleeding

266
Q

Is there unbound iron in plasma?

A

NOPE. Would be toxic to us

267
Q

What is serum iron?

A

Iron that is bound to transferrin in the blood

Remember: no free, unbound iron is in the blood

268
Q

What state does iron circulate in?

A

The ferric state (Fe III)

269
Q

What is “total iron binding capacity” (TIBC) of serum?

A

If transferrin was 100% saturated, how much iron would that be?

270
Q

How do you calculate transferrin saturation?

A

Serum Iron / TIBC

271
Q

What percentage of transferrin molecules in the blood are occupied with iron? What percentage are open?

A

1/3 occupied, 2/3 open

272
Q

What is ferritin?

A

Cellular iron is stored in ferritin. We obviously cannot measure intracellular stores of iron but we can measure the ferritin that leaks into the plasma

273
Q

What is hemosiderin?

A

Ferritin that has been engulfed by a lysosome. This is stainable and viewable within a cell

274
Q

What causes an increase in ferritin but NOT an increase in total body iron?

A

Chronic disease/inflammation, liver disease, metabolic syndrome, and hemophagocytic syndrome

275
Q

What is the normal range for total body iron?

A

3.5 - 5g

276
Q

What percentage of iron in the body is functional vs. in storage?

A

75% functional, 25% storage

277
Q

How much iron recirculates daily?

A

20-25 mg

278
Q

How is iron balanced maintained?

A

We lose 1-2 mg per day via bleeding or sloughed enterocytes but we absorb 1-2 mg per day via duodenal enterocytes

279
Q

What acid is necessary to proper digestion of iron?

A

HCl

MS1 Fall (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions