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Macronutrients > Exam #2 > Flashcards

Exam #2 Flashcards

1
Q

Carbohydrate Structure

A

(CH2O)n are aldehydes or ketones containing multiple hydroxyl (OH) groups.

Simple - mono and di-saccharides

Complex - oligo (3-10 sugar units) and polysaccharides (10+ sugar units)

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2
Q

Glycosidic Bonds

A

are how monosaccharides are joined to form oligo and polysaccharides

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3
Q

Glycoproteins & Glycolipids

A

CHO maybe complexed with proteins or lipids

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4
Q

Monosaccharides

A

glucose, fructose, galactose

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5
Q

Glucose

A

Principle source of energy

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6
Q

Glucose Structure

A
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7
Q

Glucose on Cell Surface

A

Recognition for communication purposes

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8
Q

Fructose

A

Monosaccharide - fruit, corn-syrup in processed foods

simple CHO

sweetest sugar

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9
Q

Fructose Structure

A
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10
Q

Galactose

A

monosaccharide

compare structure to glucose to identify

image of Beta D galactose

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11
Q

Pentoses

A

Monosaccharides Ribose (5C) and Deoxyribose comprise part of RNA and DNA

Ribitol - reductuction product of ribose, constituent of riboflavin and the flavin coenzymes; FAD and FMN

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12
Q

Disaccharides

A

lactose, sucrose, maltose

two monosaccharide units joined by convalent bonds

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13
Q

Lactose

A

Disaccharide - Milk

Made of glucose and galactose

simple CHO

can’t absorb stays in gut

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14
Q

Lactase

A

enzyme that breaks down lactose

beta - hard to break down in body you need lactase enzyme in order to do so

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15
Q

Sucrose

A

Disaccharide - Table sugar, cane, and beet sugar

made of glucose and fructose

simple CHO

2nd sweetest sugar

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16
Q

Maltose

A

Disaccharide - Beer and malt liquors

made of glucose and glucose

simple CHO

doesn’t normally occur naturally

brush border digests

formed from hydrolysis of starch

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17
Q

Oligosaccharides

A

3-10 sugar units

raffinose, stachyose, and veracose

complex CHO

attaches monosaccharides via acetal (glycosidic bonds) to form short chain polymers

Formed between OH group of one sugar unit and OH group of next with elimination of water (condensation)

can be alpha or beta based on anomeric carbon before bond was formed

not common - disaccharides are more common

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18
Q

Polysaccharides

A

>10 sugar units

starch, glycogen, dietary fiber

complex CHO

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19
Q

Homopolysaccharide

A

structure is composed of a single type of monomeric (monosaccharides) unit

in greater abundance than heteropolysaccharides

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20
Q

Heteropolysaccharides

A

two or more different types of monosaccharides make up its structure

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21
Q

Starch

A

Polysaccharides (more than 10 sugar units) - (amylose and amylopectin)

wheat, rice, corn, barley, oats, legumes, breads, cereals, legumes

Starch is storage form of CHO in plants.

made of glucose

Complex CHO

ALL starch is ALPHA LINKAGE

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22
Q

Amylose

A

starch (breads, cereals, and legumes)

linear, unbranched structure

15-20% of total starch content

alpha-1-4 glycosidic linkage

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23
Q

Amylopectin

A

starch (breads, cereal, legumes)

80-85% of total starch content

branched chain polymer

alpha-1-6 glycosidic linkage makes branch point linkage

alpha-1-4 glycosidic linkage connects glucose units

requires 2 enzymes to breakdown due to different linkages

high degree of branching but not as much as glycogen

provides a large number of nonreducing ends from which glucose residues can be cleaved and used for energy

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24
Q

Glycogen

A

Polysaccharide (more than 10 sugar units)

human made in the skeletal muscle and liver

Glycogen is storage form of CHO in aminals.

made of glucose

Complex CHO

highly branched is most effective attracts less water and more enzymes can work on it

can be hydrolyzed from nonreducing ends of glycogen chains

provides a large number of nonreducing ends from which glucose residues can be cleaved and used for energy by entering into energy releasing pathways

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25
Q

Dietary Fiber - Cellulose

A

homopolysaccharide (glucose) - rough part of grains and fruit

provides structure in the cell walls of plants

dietary fiber - bulking agent and energy souce for bacteria

considered dietary b/c can’t be digested by mammals

contains beta-1-4 glycosidic linkage therefore resistant to digestive enzyme alpha-amylase which favors alpha-1-4 linkages

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26
Q

Chiral Carbon

A

has 4 different atoms or groups attached

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27
Q

D Isomeric Forms

A

OH group is to the right

all naturally occurring sugars are D

enzymes are specific and will only work on D or L NOT BOTH

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28
Q

L Isomeric Forms

A

OH group of the chiral C is to the left

enzymes are specific and will only work on D or L NOT BOTH

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29
Q

Anomeric Carbon

A

The carbon that forms a ring structure with the reducing carbon reacting with OH group on the highest numbered chiral carbon of monosaccharide.

the carbon atom comprising the carbonyl function

anomeric carbon is the new asymmetric center

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30
Q

Alpha

A

FORM: when OH group of anomeric carbon is drawn below the plane of ring

DOWN

Starches - soluble and easily digested

LINKAGE: (disaccharides)

Humans can digest alpha because enzyme is made to support alpha linkage.

straight

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31
Q

Beta

A

FORM: when OH group is above the plane of the ring

UP

Fiber (can’t digest-only animals and bacteria)

Cellulose formed when synthesized from beta-glucose units is INSOLUBLE and cannot be digested as a food source by most animals

LINKAGE: (disaccharides)

zigzag

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32
Q

Polysaccharide Digestion

A

Mouth - salivary alpha-amylase hydrolyzes alpha-1-4 linkages

amylose->dextrins amylopectin->dextrins

Stomach no digestion pH too low inactivates enzyme

Small intestine - pacreatic alpha-amylase hydrolyzes alpha-1-4 linkage; bicarbonate in duodenum elevates pH

dextrins-> maltose dextrins->maltose and limit dextrins

Brush Border of SI (disaccarides)

amylose - maltose (maltase) -> glucose

amylopectin - maltose (maltase)-> glucose

limit dextrins (alpha-dextrinase) -> glucose

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33
Q

Resistant Starches

A

crystalline starch is insoluble in water and nondigestible

when heated becomes digestible but upon cooling reverts back

starches can be chemically modified to resist digestion by increasing crosslinking between chains

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34
Q

Disaccharide Digestion

A

Mouth - no digestion

Stomach - no digestion

Upper Small Intestine - microvilli of the intestinal mucosal cells (enterocytes) the brush border

enzymes located on enterocytes lactase, sucrase, maltase, and isomaltase

lactose (lactase catalyzes clevage) ->galactose & glucose

sucrose (sucrase hydrolyzes) -> glucose & fructose

maltose (maltase hydrolyzes) -> glucose & glucose

Isomaltose (isomaltase or alpha-dextrinase from amylopectin hydrolyzes alpha-1-6 linkage) -> glucose & glucose

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35
Q

Absorption - enterocyte to blood

A

once food is digested nutrients must move into the cells of the GI tract by the process absorption

The wall of the small intestine is composed of absorptive mucosal cells that line projections called villi that extend into the lumen.

On the villi are absorptive cells (enterocytes) that have microvilli (brush border)

diffusion - particles move from high to low concentration

facilitated diffusion-carrier want equalization of substance each side of membrane

active transport-concentration only on one side. requires ATP and Na+. one directional carriers

pinocytosis- large molecules cell membrane engulfs

36
Q

Absorption of Glucose & Galactose

A

Into CELL: Active Transport - SGLT1 (sodium glucose transporter 1) uses ATP to transport sugar through mucosal cell. 1 glucose and 2 Na+ are transported into mucosal cell of the SI at one time. carrier used to cross cell membrane

Into BLOOD: Diffusion GLUT2 transports glucose from the intestinal mucosal cell (enterocyte) into the portal blood. dependent on blood glucose concentration

37
Q

Absorption of Fructose

A

Into CELL: facilitated transport - GLUT5 fructose transported into the mucosal cell of SI

Into BLOOD: GLUT2 factilitated transport fructose transported from the mucosal cell of SI

absorbed by the liver where it is phosphorylated and trapped (no fructose in blood)

limited in 60% of adults

fructose absorption is slower than glucose and galactose

38
Q

Transport

A

going from blood to other tissues

39
Q

Galactose and Fructose Transport

A

transport across the wall of intestine into portal circulation

portal circulation -> directly to liver (major site of metabolism) through specific hepatocyte receptors

enters liver cells by facilitated transport and metabolized

converted to glucose derivatives and have same fate as glucose

in liver-> converts to glucose-> stored as glycogen or catabolized

40
Q

Glucose Transporter (GLUT)

A

glucose is highly polar

cell (lipid bilayer) membrane is nonpolar matrix

the family of integral protein carriers involved in this process are glucose transports (GLUT)

glucose enters cell through these proteins that are embedded within cell membrane. FACILITATED DIFFUSION

these integral proteins (12) have specific combining site

these proteins undergo conformational change upon molecule binding which allows the molecule to be TRANSLOCATED to the other side of the membrane and released

can reverse this conformational change when molecule is unbound so that the process can be repeated

41
Q

Insulin - Cellular Absorption

A

insulin - anabolic hormone involved in glucose synthesis and storage released by Beta-cells of pancreas

role in cellular glucose uptake

binds to membrane receptor

stimulates GLUT4 to move to membrane

Maintains blood glucose levels

insulin receptor in mucles and liver

muscles=use

liver=store

  1. ) stimulates uptake of glucose by muscle and adipose
  2. ) Inhibits the synthesis of glucose (glyconeogenesis)

The rise in blood glucose following a CHO meal triggers release of insulin while reducing the secretion of glucagon.

42
Q

Insulin Receptor

A

doesn’t take glucose into cell

insulin - anabolic hormone involved in glucose synthesis and storage

insulin -> receptor -> 2nd messenger (signal) -> stimulates uptake of glucose -> to glycogen to store or

insulin binds to it’s receptor intracellular domain changes shape which cause chain of reactions that activate certain enzymes.

more glucose transporter proteins are released from intracellular stores and move to the plama membrane and become embedded

43
Q

GLUT4

A

insulin regulated

GLUT4 concentration on plasma membrane increases in response to the hormone insulin

more membrane transporters = increase in glucose uptake

skeletal muscle and adipose tissue are responsive to insulin

muscle, heart, brown and white adipocytes

44
Q

GLUT3

A

high affinity glucose transporter with expression in those tissues that are highly dependent on glucose

Brain

45
Q

Glucose Distribution

A

muscles, kidney, and adipose

kidney - liver can’t filter glucose out not suppose to have C units in urine diabetes= sweet urine kidney damage

uptake of glucose by skeletal and adipose tissue are insulin dependent (GLUT4)

uptake by liver is insulin independent

46
Q

Glycemic Response to Carbohydrates

A

the rate glucose is absorbed from intestinal tract is important in controlling the homeostasis of blood glucose, insulin release, obesity, and possible weight loss.

47
Q

Glycemic Index

A

increase in blood glucose level over the base-line level during a 2 hour period following consumption of a defined amount of carbohydrate (usually 50 g) compared with the same amount of CHO in a reference food

high glycemic food cause a spike in bld glu levels

low glycemic food not as bad of a spike

PTN and FAT slow digestion

48
Q

Glycemic Load

A

Glycemic load = glycemic index X g of CHO in a serving

High GL = increase bld glu

takes into account that we don’t just eat single food but meals made up of a number of foods

49
Q

Metabolic Pathways of Carbohydrate Metabolism

A

glycogenesis - making glycogen

glycoenolysis - breakdown glycogen

glycolysis - oxidation of glucose

gluconeogenesis - produce glucose from nonCHO intermediates

hexose monophosphate shunt - production of 5C monosaccharides from NADPH

TCA - oxidation of pyruvate and acetyl CoA

50
Q

Glycogenolysis

A

The pathway by which glycogen is enzymatically broken down to individual glucose units in the form of glucose-1-phosphate

hormone regulated

  1. glucagon (pancreas)
  2. epinephrine (adrenal medulla)

both hormones function through the second messenger cAMP which regulates phosphorylation state of enzymes

phosphorolysis- glycogen glycosidic bonds are cleaved by adding a phosphate

reaction is catalyzed and regulated by glycogen phosphorylase (muscle and liver)

51
Q

Glycogenesis

A

conversion of glucose to glycogen (insulin stimulates)

important in hepatocytes bc **liver **(maintaining glucose homeostasis) is major source of glycogen synthesis and storage

other major site of storage is skeletal muscle (used for energy) and to a lesser extent also adipose tissue

52
Q

4 Fates of Glucose

A
  1. Glycogen Synthesis - (Glycogenesis) reversible

stimulated by high glucose (liver), insulin, low glycogen (muscle)

  1. ATP Synthesis - produce energy NOT reversible

Glycolysis - low energy produced, cytoplasm, anaerobic

glucose -> pyruvate releases ATP

Anaerobic Glycolysis = 2 ATP/glucose and maintain blood glucose. pyruvate to lactate

RBCs, WBCs, kidney medulla, enterocytes, lens, cornea, skin, and skeletal muscle (rely on glycolysis bc lack mitochondria)

Aerobic Glycolysis = 38 ATP/glucose and maintain blood glucose

glucose->pyruvate->acetyl-CoA->TCA

brain, liver, skeletal muscle, kidney cortex

TCA - high energy produced, mitochondria, aerobic

upon completion of acetyl-CoA through TCA -> lots of ATP!!

Stimulated: high glucose, low ATP, insulin

Inhibition: high ATP, FFAs

  1. FFA Synthesis - fatty acid production NOT reversible (only occurs if excess calories are consumed)

Acetyl-CoA->FFA synthesis->TG (liver and adipocytes)

Stimulated: high glucose, high ATP, and insulin

  1. NEAA Synthesis - amino acids reversible
53
Q

Glycolysis

A

glucose degraded into 2 pyruvate

Anaerobic -> pyruvate to lactate from muscle can then move to the blood stream and be carried to the liver for conversion into glucose. releases only small amount of energy to help sustain muscles

Aerobic -> pyruvate transported to mitochondria goes through TCA completely oxidized to CO2 and H2O and ATP

notes: pyruvate->acetyl CoA->TCA->electrons enter ETC=ATP

54
Q

Glycolysis: Step 1

A

Glucose phosphorylated to Glucose-6-Phosphate

Enzymes: glucokinase (Liver) and hexokinase (liver or other tissues)

Rate-limiting step - 1 ATP consumed

irreversible (unless use G-6-phosphotase in liver) liver isn’t selfish will return glucose back to blood

glucokinase and G-6-phosphotase enable the liver to regulate blood glucose levels

adding phosphate traps glucose into cell (when BGL are high)

hexokinase is inhibited by G6P competes for active site and by allosteric interactions at a separate site on enzyme

glucokinase has high km for glucose (prevents too much glucose being removed from blood). only active at high glucose. not inhibited. allows glucose to be stored at glycogen in liver only when blood glucose is high

ATP-> ADP

Phosphate added to glucose-6-phosphate

55
Q

Glycolysis: Step 2

A

G6P isomerized to Fructose-6-phosphate

Enzyme: phosphoglucose isomerase

smaller ring but still 6 carbons

56
Q

Glycolysis: Step 3

A

F6P phosphorylated to fructose-1,6-bisphosphate

Enzyme: catalyzed by phosphofructokinase (PFK)

Irreversible - Rate limiting

allosteric Inhibitors: ATP, citrate, certain FA, increase in blood concentration of H ions

Activators: AMP, ADP, and fructose 2,6-bisphosphate produced from fructose 6-P using enzyme phosphofructose kinase 2 (PFK2)

low ATP speeds reaction up

ATP -> ADP

phosphate added to fructose-1,6-bisphosphate

57
Q

Glycolysis: Step 4

A

F 1,6 bisP into glyceral dehyde-3-phosphate (G3P) and dihydroxyacetone (DHAP)

Enzyme: aldolase

G3P and DHAP are each 3C units

58
Q

Glycolysis: Step 5

A

DHAP is converts to G3P

Enzyme: triosephosphate isomerase

G3P = glyceraldehyde-3-phosphate

59
Q

Glycolysis: Step 6

A

G3P is oxidized and phosphorylated to 1,3-bisphosphoglycerate

enzyme: G3-P dehydrogenase

requires NAD and inorganic P

produces NADH (energy producing)

NADH = 3ATP

60
Q

Glycolysis: Step 7

A

1,3-bisphosphoglycerate to 3-phosphoglycerate

enzyme: phosphoglycerate kinase

substrate level phosphorylation

2 ATPs produced from 1 glucose

Net ATP=0

ADP -> ATP

phosphate removed from 1,3-bisphosphoglycerate

61
Q

Glycolysis: Step 8

A

3-phosphoglycerate to 2-phosphoglycerate

Enzyme: phosphoglycerate mutase

reversible

phosphate group transfer from carbon 3 to carbon 2

62
Q

Glycolysis: Step 9

A

2 phosphoglycerate to phosphoenolpyruvate + H2O

enzyme: enolase

Dehydration rxn

reversible

forms a double bond between the 2nd and 3rd C

63
Q

Glycolysis: Step 10 RLR

A

phosphoenolpyruvate (PEP) to pyruvate

enzyme: pyruvate kinase (PK)

transfer of phosphate from phosphoenolpyruvate (PEP) to ADP

substate level phosphorylation

IRREVERSIBLE

net yields 2 ATPs per glucose molecule

PK inhibited by ATP and alanine

PK activated by Fructose 1,6 bisphosphate

PK is regulated by covalent phosphorylation inhibited by phosphorylation

ADP -> ATP

phosphate removed from 2nd Carbon

64
Q

Glycolysis: Step 11

A

pyruvate to lactate

enzyme: lactate dehydrogenase

under anaerobic conditions (fermentation)

NADH+ and H+ have 2H and electrons removed and given to pyruvate

NADH->NAD

NAD formed from this reaction can replace NAD needed in step 6 of glycolysis

65
Q

RLR Rxns

A

3 enzymes catalyze highly spontaneous rxns

  1. hexokinase
  2. phosphofructokinase (PFK)
  3. pyruvate kinase

control of these enzymes determines the rate of glycolysis

IRREVERSIBLE RXNs

66
Q

Glycolysis ATP counting

A

Glucose

step 1 use 1 ATP = -1

step 3 use 1 ATP= -2

step 6 gain NADH (3 ATP) per G3P = 2 NADH

step 7 gain 2 ATP = 0

step 10 gain 2 ATP per glucose = 2

Pyruvate

step 11 (anaerobic) use NADH (-3 ATP) = -2 NADH

NAD too big to leave cytosol need shuttle system

glucose + 2NAD + 2ADP + 2P ->

2 pyruvate + 2NADH + 2 ATP

67
Q

Shuttle Systems

A

NADH (hydrogens and electrons) produced by glycolysis cannot enter mitochondria directly in order to be oxidized by ETC

  1. Malate - Aspartate shuttle system

liver, kidney, and heart

2 NADH from glycolysis = 6 ATPs + 2 ATP from glycolysis = 8 ATPs

  1. G3P shuttle system (dominate)

brain and skeletal muscle

2 NADH from glycolysis -> 2 FADH2 = 4 ATPs + 2 ATP from glycolysis = 6 ATPs

68
Q

Location Change

A

glycolysis is in cytosol of cell

pyruvate goes to mitochondrion to be further metabolized

inner membrane of mitochondria permeability barrier

matrix contains pyruvate dehydrogenase of TCA

69
Q

Pyruvate to Acetyl-CoA

A

3C -> 2C + CO2

enzyme: pyruvate dehydrogenase (PDH)

oxidative decarboxylation of pyruvate

produce NADH and CO2

NADH = 3 ATPs

IRREVERSIBLE - acetyl CoA is also produced from fatty acids (no fatty acid to glucose possible)

Important bc ready for TCA and fatty acid synthesis

Regulated by Inhibition

NADH competes with NAD for E3 binding

Acetyl CoA competes with CoA for E2 binding

70
Q

TCA Cycle

A

presence of oxygen

pathway for oxidation of amino acids, fatty acids, and carbohydrates

6C goes CO2 -> 5C goes CO2 -> 4C

3CO2 , 4NADH , 1 FADH2 , 1 ATP produced

1 NADH produced when pyruvate goes to acetyl CoA

71
Q

TCA: Step 1

A

Acetyl CoA (2C) + Oxaloacetate (4C) + H2O -> Citrate (6C) + CoA

enzyme: citrate synthase

condensation rxn

72
Q

TCA: Step 2

A

Citrate (6C) -> Isocitrate (6C)

enzyme: aconitase

isomerization

73
Q

TCA: Step 3 RLR

A

Isocitrate (6C) + NAD -> Alpha-ketoglutarate (5C) + CO2 + NADH + H

enzyme: isocitrate dehydrogenase

oxidatve decarboxylation

Allosteric Enzyme

inhibited by NADH and ATP

activated by ADP

too much product then acetyl coa goes to fatty acid synthesis instead and entire pathway shutdown

NADH=3 ATPs

74
Q

TCA: Step 4

A

alpha-ketoglutarate (5C) + NAD -> Succinyl-CoA (4C) + CO2 + NADH + H

enzyme: alpha-ketoglutarate dyhydrogenase

oxidative decarboxylation

NADH=3 ATPs

multienzyme complex composed of 3 subunits E1, E2, E3

requires CoA, NAD, TPP, Lipoic Acid, and FAD

Allosteric enzyme

inhibited by increased levels of succinyl CoA, NADH, ATP

75
Q

TCA: Step 5

A

Succinyl-CoA (4C) + P -> Succinate (4C) + CoA

enzyme: succinyl-CoA synthetase

bond hydrolyzed energy released used for substrate level phosphorylation

GDP phosphorylated to GTP

require inorganic phosphate

GTP=1ATP

76
Q

TCA: Step 6

A

Succinate (4C) + FAD -> Fumarate (4C) + FADH2

enzyme: succinate dehydogenase

oxidation rxn

enzyme is integral protein of inner mitochondrial matrix

SDH enzyme requires coenzyme

uses FAD instead of NAD

FADH oxidized in ETC to produce 2 ATPs

77
Q

TCA: Step 7

A

Fumarate (4C) + H2O -> Malate (4C)

enzyme: fumarase

hydration rxn

lose double bond

78
Q

TCA: Step 8

A

Malate (4C) + NAD -> Oxaloacetate (4C) + NADH + H

enzyme: malate dehydrogenase

oxidation rxn

NADH=3ATPs

79
Q

TCA ATP Counting

A

acetyl CoA

step 3 NADH = 3 ATPs

step 4 NADH = 3 ATPs

step 5 GTP = 1 ATP

step 6 FADH2 = 2 ATPs

step 8 NADH = 3 ATPs

oxaloacetate

12 ATPs x 2 acetyl CoA = 24 ATPs

80
Q

ETC

A

inner mitochondrial membrane

oxidative phosphorylation occurs

oxidation of a metabolite by oxygen

and

phosphorylation of ADP

Electron carries are substances that make up ETC

contain prosthetic groups which are either e- acceptors (oxidizing agent) or e- donors (reducing agent)

downhill flow of electrons

from NADH to FADH2 to O2

81
Q

ETC Image

A

electrons pass in ETC

H+ are translocated to inner membrane space creating electrical charge and pH difference

Complex I - NADH + H to NAD electrons pass to CoQ and 4 H+ to intermembrane. enzyme: NADH dehydrogenase

Complex II - FADH2 to FAD electrons and hydrogens pass to CoQ. enzyme succinate dehydrogenase

CoQ transports electrons to Complex III

Complex III - H to intermembrane heme (Cu & Fe)

Cyt C transports electrons to Complex IV

Complex IV - reduces O2 to form H2O heme (Cu & Fe)

electrical change and pH difference provide driving energy

Complex V - ATP-synthase enzyme protein changes conformation results in ATP synthesis and movement of H back to mitochondrial matix

heme holds apart electrons until 4 are acheived then gives

82
Q

Hexosemonophosphate Shunt

A

pentose phosphate pathway

purpose is to generate intermediates

Products:

  1. Pentose Phosphates - for DNA, RNA, and nucleotide synthesis
  2. reduced cosubstrate NADP to NADPH - reducing agent for biosynthesis of fatty acids and cholesterol

very efficient - recycling 2 ribose to fructose-6-phosphate to glucose

83
Q

Gluconeogenesis

A

formation of glucose by liver or kidney from nonCHO precursors

purpose: maintain blood glucose level: fasting sustained excercise, stress, and hypoglycaemia

when glucose storage is low or tissue without mitochondria (anaerobic) rely on it (nerve cells and RBC)

pyruvate to PEP has to be done by OAA by pyruvate carbosylase

PEP to pyruvate by phyruvate kinase

lactate -> pyruvate (cyto) moves to mito

amino acids -> pyruvate or oxaloacetate in mito

glycerol -> DHAP -> G3P all in cyto

bypass irreversible steps in glycolysis to produce glucose

84
Q

Pyruvate Carboxylase

A

pyruvate (3C) to OAA (4C)

step 1 of gluconeogenesis

allosteric enzyme postively regulated by Acetyl CoA

Pyruvate + HCO3 + ATP <-> OAA + ADP + P + H

elongation process

need bicarbonate

when low CHO pyruvate has to be from AAs, lactate, glycerol to make OAA needed for TCA

starvation, low CHO diet, infection, and trauma

glucose needed for anaerobic tissues brain RBC

85
Q

CHO RDA

A

male or female 130 g/day

86
Q
A

Macronutrients (4 decks)

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