CURB THE CARB Flashcards
per mole of glucose, ilang ATP meron?
36 or 38 moles of ATP
CHO can generate reducing equivalents in the form of
NADPH
RIBOSE: nucleic acids
_______: milk
galactose
glucose is major fuel for fetus by the ____ trimester
3rd, max transfer of nutrients from mother to baby
dietary fibers: ___ & ___ binds lipid compounds such as cholesterols
Pectin and Lectin
Thus, these lower blood cholesterol levels
Pyruvate converted to Alanine by what pathway?
Gluconeogenesis (AA to glucose)
30 to 40% of CHO digestion happens in the
mouth by salivary amylase (ptyalin)
linkages: 1,4 glycosidic ng amylose and amylopectin
pH: 6-7 pH at mainactivate siya by less than 4 pH
end products: dextrin, maltose
Sa small intestine naman ang final digestion of CHO by enzymes _______
pancreatic amylase (amylopsin) oligosaccharides from brush border of small intestine
enzyme -> CHO sucrase: sucrose lactase (beta-galactosidase): lactose maltase (alpha-glucosidase): maltose isomaltase (alpha 1,6 glucosidase): \_\_\_\_\_\_\_
alpha 1,6 glycosidic bonds
What part of the small intestine is CHO absorbed?
jejunum
What is the most rapidly absorbed CHO?
Galactose
What is the most LEAST rapidly absorbed CHO?
Pentoses
Fate of 50% glucose?
ENERGY (glycolysis)
Fate of 30-40% glucose?
FATS
Fate of 10% glucose?
GLYCOGEN (muscles, liver)
Insulin facilitates the entry of glucose inside cell EXCEPT in
LIVER
possible ang conversion ng G6P to glucose using ____
GLUCOSE-6-PHOSPHATASE pero nasa liver lang siya
why is hexokinase used first in the pathway?
kasi pwede siya gamitin kahit mababa levels ng glucose mo
bakit tinawag na “specific enzyme” ang glucokinase?
ACTS ONLY ON GLUCOSE
(induced by insulin) -> high levels of glucose
Oxidative degradation to CO2
energy formation by krebs cycle from glycolysis
FATES OF G6P?
uronic acid pathway krebs cycle/TCA glycolysis HMP shunt (degradation) blood glucose, energy, FA, cholesterol, glycogen
aerobic: glucose -> pyruvate
anaerobic: glucose -> _____
LACTATE
GLYCOLYSIS happens where in the cell?
CYTOSOL (exergonic to ah. energy producing MOSTLY)
What does RBC and cornea, lens, retina in relation to glycolysis?
lack mitochondria, anaerobic glycolysis
In the absence of glucose in the brain, the _____ is metabolized by brain tissue
ketone bodies
① Glucose 🡆G6P (first priming reax)
enzyme: ________
hexokinase
uses ATP
start of preparatory phase
1ST irreversible step
② G6P 🡆 F6P
enzyme: ________
phosphohexose isomerase (PHI)
aldose 🡆 ketose
REVERSIBLE
ISOMERIZATION
③ F6P 🡆 F1,6BP (second priming reax)
enzyme: ________
PFK1 (phosphofructokinase 1)
uses ATP
rate-limiting enzyme
2ND irreversible step
④ F1,6BP 🡆 GD3P + DHAP
enzyme: ________
Aldose - cleavage enzyme 2 sugars to 3 carbons each GD3P - aldose DHAP - ketose ISOMERIZATION
⑤ GD3P 🡆 G3P(2)
enzyme: ________
Triosephosphate isomerase (TPI)
⑥ G3P(2) 🡆 1,3BPG(2)
enzyme: ________
G3PDH
start of pay off phase
oxidoreduction-phosphorylation
NADH 🡆 NAD 🡆 oxidation (H+ enter ETC in mitochondria to produce ATP)
⑦ 1,3BPG(2) 🡆 3PG(2)
enzyme: ________
PGK (phosphoglycerate kinase)
1st ATP forming reaction
transferase reax
substrate level phosphorylation
⑧ 3PG(2) 🡆 2PG(2)
enzyme: ________
PGM (phospho-glycerate mutase)
phosphate change from pos. 3 🡆 pos. 2
ISOMERIZATION
⑨ 2PG(2) 🡆 PEP(2)
enzyme: ________
Enolase (inhibited by fluoride)
releases H2O(2)
DEHYDRATION
⑩ PEP(2) 🡆 Pyruvate(2)
tautomerizes into its KETO FORM
enzyme: ________
PK (Pyruvate Kinase)
3rd irreversible step
2nd ATP forming reaction
substrate level phosphorylation
1 mol glucose 🡆 aerobic glycolysis by MAS 🡆 total ATPs would be?
Gross ATP: 9
Net ATP: 7
[reax #6 = 5 ATP]
1 mol glucose 🡆 aerobic glycolysis by G3PS 🡆 total ATPs would be?
Gross ATP: 7
Net ATP: 5
[reax #6 = 3 ATP]
1 mol glucose 🡆 anaerobic glycolysis 🡆 total ATPs is?
Gross ATP: 4
Net ATP: 2
[no ATP on reax #6]
reax #7 and #10 lang meron
Starting at F1,6BP, it will produce how many NET ATPs?🡆 aerobic glycolysis by MAS
Gross ATP: 9
Net ATP: 9
tandaan, reax #6 siya nag start so walang bawas na ATP
If ang reaction #6 sa glycolysis ay anaerobic, ano fate ng NADH?
pyruvate 🡆 lactate
enzyme: lactate dehydrogenase
What inhibits pyruvate kinase?
ATP, alanine, FA, acetyl-coA
What stimulates pyruvate kinase?
F1,6BP
pyruvate 🡆 transamination = ?
pyruvate + NH2 = alanine
pyruvate 🡆 oxidative carboxylation = ?
acetyl coA (recall: Pyruvate dehydrogenase complex)
quickie: 3 enzymes ng PDH complex?
Pyruvate dehydrogenase ①
Dihydrolipoyl Transacetylase ②
Dihydrolipoyl Dehydrogenase ③
R group ng pyruvate dehydrogenase?
① Thiamine pyrophosphate (TPP)
vit B1
R group ng DHLT?
Transfer of acetyl group to coA
② Lipoamide CoASH
vit B5
R group ng DH dehydrogenase?
regeneration of oxidized lipoamide
③ FAD = vit B2
NAD = vit B3
If any of the enzymes in PDH complex is blocked, what happens?
lactic acid will accumulate 🡆 lactic acidosis
what is the importance of b vitamins in the fate of pyruvate?
pyruvate cannot be converted to acetyl-coA w/o B vitamins 🡆 beri-beri
These inhibit PDH complex
Arsenite & Mercuric ions - reacts with the -SH of lipoic acid
Thiamine deficiency - alcoholics
In the cori cycle or lactic acid cycle, lactate is produced by ______ glycolysis in the muscles 🡆 liver 🡆 converted to glucose 🡆 muscles 🡆 lactate
anaerobic glycolysis
The cori cycle includes both
glycolysis and gluconeogenesis
80% of acetyl coA 🡆 ______ 🡆 maximize ATP production
krebs cycle (reuires insulin to enter)
Triglyceride 🡆 _____ 🡆 free FA 🡆 beta-oxidation 🡆 acetyl coA
lipolysis
Protein 🡆 _______ 🡆 AA 🡆 deamination & oxidation 🡆 acetyl coA
proteolysis
glycogen 🡆 glycogenolysis 🡆 glucose 🡆 glycolysis 🡆 pyruvate 🡆 ______ 🡆 acetyl coA
oxidation
What happens when there is no insulin?
acetyl coA cannot enter krebs
➀ formation ketone bodies
② formation cholesterol
α-ketoglutarate is a precursor of
glutamic acid
oxaloacetate is a precursor of
aspartic acid
1st reaction of the kreb cycle depends on
availability of acetyl coA
availability of oxaloacetate
concentration of succinyl coA
succinyl coA inhibits ______
citrate synthase
① Acetyl coA + oxaloacetate =
citrate
1st rate limiting step
𝕔𝕠𝕟𝕥𝕣𝕠𝕝 𝕡𝕠𝕚𝕟𝕥
CONDENSATION
② Citrate 🡆 Isocitrate
enzyme: Aconitase
what reaction is this?
dehydration/rehydration reaction
REVERSIBLE
③ Isocitrate 🡆 α-ketoglutarate
enzyme: isocitrate dehydrogenase
what reaction is this? what does it release?
NAD dependent ATP = 2.5 release of CO2 𝕔𝕠𝕟𝕥𝕣𝕠𝕝 𝕡𝕠𝕚𝕟𝕥 OXIDATIVE DECARBOXYLATION
TOP 3 importance of the Krebs cycle?
synthesis of NADH
precursors for amino acids
release of stored energy through oxidation of acetyl coA
mnemonics for the krebs cycle/citric acid cycle/tricarboxylic acid cycle
Our - Oxaloacetate City - Citrate Is - Isocitrate Kept - alpha-ketoglutarate Safe and - succinyl-coA Sound - succinate From - fumarate Malice - malate
What reaction in the krebs cycle is energy conserving?
Reax ⑤ Succinyl-coA 🡆 Succinate
enzyme: Succinyl coA synthase
1 ATP is produced
subtrate level phosphorylation
④ α-ketoglutarate 🡆 succinyl-coA
enzyme: α-KGD complex
How many ATPS are produced?
2.5 ATP
NAD dependent
𝕔𝕠𝕟𝕥𝕣𝕠𝕝 𝕡𝕠𝕚𝕟𝕥
release of CO2
⑥ succinate 🡆 fumarate
enzyme: succinate dehydrogenase
1.5 ATP
𝕔𝕠𝕟𝕥𝕣𝕠𝕝 𝕡𝕠𝕚𝕟𝕥
dehydrogenation
H+ pass through FAD (complex II ng ETC)
⑦ fumarate 🡆 malate
enzyme: fumarase
addition of H2O
HYDRATION
⑧ Malate 🡆 Oxaloacetate
enzyme: Malate dehydrogenase
2.5 ATP
NAD dependent
DEHYDROGENATION
Total ATP produced by one cycle of krebs cycle?
[Oxidative phosphorylation - 9 ATP]
[Substrate phosphorylation - 1 ATP]
Add 2 mol pyruvate that entered = 10 x 2
20 ATP
glucose 🡺 complete oxidation 🡺 G3PS 🡺 total ATPs?
Gross ATP: 32
Net ATP: 30
glucose 🡺 complete oxidation 🡺 MAS 🡺 total ATPs?
Gross ATP: 34
Net ATP: 32
glucose 🡺 complete oxidation 🡺 MAS 🡺 total ATPs through oxidative phosphorylation?
Gross ATP: 23
Net ATP: 21
1 mol of α-ketoglutarate 🡆 krebs cycle 🡆 total ATPS produced?
7.5 ATP 4th = 2.5 5th = 1 6th = 2.5 8th = 2.5 total = 7.5 ATP
F1,6BP 🡆 complete oxidation 🡆 G3PS 🡆 total ATPs produced?
Gross ATP: 32
Net ATP: 32
Vitamins that play important role in krebs cycle?
B1, B2, B3, B5
Glycolysis and Glycogenesis 🡆 _______ pathways
Stimulated by insulin
HYPOglycemic (blood sugar lower than normal)
Glycogenolysis and Gluconeogenesis 🡆 ______ pathways
Stimulated by glucagon
HYPERglycemic (blood sugar higher than normal)
Major gluconeogenic precursors: Lactate Glycerol Glucogenic AA \_\_\_\_\_\_\_ sa animals
Propionate
What is LIPOLYSIS?
breakdown of fats into fatty acids and glycerol
What is GLYCOGENOLYSIS?
breakdown of glycogen to glucose
what are the 3 steps in glycolysis that should be reversed?
PEP 🡆 Pyruvate
F6P 🡆 F1,6BP
Glucose 🡆 G6P
Why is there a need for pyruvate to be converted to malate first before exiting the mitochondria?
There is no OXALOACETATE TRANSPORTER in there.
Oxaloacetate 🡆 PEP
what is the enzyme used?
PEPCK (Phospho-enol-pyruvate Carboxykinase
Remember that F2,6BP:
stimulates ______
inhibits _______
glycolysis
gluconeogenesis
Fact! what is the most potent ALLOSTERIC ACTIVATOR of PFK1?
F2,6BP
HMP shunt occurs in what part of the cell?
CYSTOSOL
It is the oxidation of G6P 🡆 pentose phosphates
2 Major functions of HMP shunt:
➀ generation of _____ for reductive synthesis
➁ production of _____ for nucleotide & nucleic acid biosynthesis
NADPH (nicotinamide adenine dinucleotide phosphate)
Ribose-5-Phosphate
In the oxidative stage of HMP shunt,
NADPH is produced as _____
G6P 🡆 ribose-5-phosphate
In the non-oxidative stage of HMP shunt,
R-5-P 🡆 F6P + _____
GD3P
ano ang glycogenesis?
intracellular synthesis of glycogen occurs in the liver and muscle
ano naman ang glycogenolysis?
intracellular degradation of glycogen
main rate-limiting enzyme: glycogen phosphorylase
