Carbohydrates II Flashcards
What is Glycolysis?
Central ATP-producing pathway
Oxydation of glucose and subsequently converted into two pyruvate molecules.
Produces energy without oxygen
Glycolysis occurs in what type of cells and what does it generate?
Takes places in the cell cytosol of all tissues and it can generate ATP
What is the end product of glycolysis and what happens to it?
2 Pyruvate
and it is fermented to lactate or transformed to Acetil-CoA
GI tract microbes in animals such as the cow and horse can ferment pyruvate into what?
into small chain fatty acids called Volatile Fatty Acids (VFA): acetate, propionate, and butyrate
this fermentation also generates additional ATP in the microbes
Phophofructokinase (PFK) catalyzes what?
catalyzes the rate-limiting step of glycolysis
In all cells, PFK activity is inhibited by what?
inhibited by increases cytoplasmic [ATP]
In the liver, PFK activity is potently stimulated by what and potently inhibited by what?
by insulin and potently inhibited by glucagon.
What is oxidation?
taking away a H molecule
What is reduction?
picking up a H+ molecule
Do reduction and oxidation happen at the same time?
yes
whenever you have a reduction there also always an oxidation and vis versa.
In glycolysis you have a net gain of how many ATP?
2
Glycolysis is the only cycle you can get energy without the use of what?
oxygen
What type of cells only do glycolysis and why?
red blood cells
they need glucose all the time
have no mitochondria
and do not need high amounts of energy
What happens to pyruvate in an anaerobic cell?
pyruvate can not be oxidized and cant be used so it is fermented into lactate as a waste product and it is sent to the bloodstream
In an aerobic cell, NAD+ will not run out. Why is this?
NADH will get oxidized in the mitochondria to get more ATP, this is known as electron transport
will also get NAD+ when NADH is oxidized in an aerobic cell
NAD+ will eventually run in an anaerobic cell so what will happen?
NADH will lose its electrons to pyruvate to get more NAD+ so that glycolysis can keep going to get more energy.
this will turn pyruvate into lactate as a waste product and it is sent into the bloodstream.
If there is too much lactate in the bloodstream, it indicates what?
too much anaerobic metabolism than normal.
What can lactate levels in the bloodstream be used for?
can be used diagnostically and prognostically.
also can use before a surgery to help show the surgical outcome.
Glycolysis occurs in which type of cells?
occurs in all cells and all the time. (every cell in the planet)
Which cells take advantage of anaerobic glycolysis?
Erythrocytes and Miocytes
What is the net gain in Glycolysis?
2 Pyruvate + 2 NADH + 2 ATP
What are the 2 stages of Glucose to Pyruvate conversion?
- Energy-investment phase
- Energy-generation phase
Energy-investment phase
First 5 reactions where ATP is used to phosphorylate intermediates.
Energy-generation phase
Second phase of glucolysis which ends with a net gain of 2 ATP, 2NADH, 2 pyruvate
In an aerobic process what happens to pyruvate?
It will transform into Acetil-CoA and it will enter the Citric Acid Cycle (TCA)
In an anaerobic process what happens to pyruvate?
Pyruvate is reduced to Lactate through fermentation
What is fermentation?
Extraction of energy in abscence of oxygen in poorly vaculirez tissues
ex. Kidney medulla
Cornea/lens
RBC that lack mitochondria
Exercising skeletal Muscle
Anaerobic glycolysis
2 ATP are generated for each molecule of glucose converted to 2 molecules of Lactate
Who can oxidize lactate from the blood to pyruvate?
The liver and the heart
What happens to pyruvate in the liver?
It can be converted to glucose in gluconeogenesis or to Acetil-CoA which will be oxidized in TCA cycle
Aerobic glycolysis
2 ATP are generated per molecule of glucose + 2NADH
How much ATP is produced by 1 NADH in the electron trasnport chain?
3 ATP (for each NADH)
What process changes pyruvate to Acetyl-CoA?
Oxidative decarboxylation
By pyruvate dehydrogenase complex (PDHC-enzyme)
What is Acetyl-CoA?
Co-enzyme, substrate for TCA cycle and carbon source for fatty acid synthesis.
What is the product after carboxylation of pyruvate?
Oxaloacetate (OOA)
Replenishes important intermediate in TCA cycle and provides substrate for gluconeogenesis
TCA cycle
TriCarboxilic-Acid Cycle
Krebs Cycle
Citric Acid Cycle
What is the Tricarboxylic acid-cycle?
Final pathway where CHOs, AA and Fatty acids converge
Where does the TCA cycle occurr?
In the mytochondria close to the electron transport chain (here Co-enzymes will be oxidized)
Is the TCA cycle aerobic or anaerobic?
Aerobic because oxygen is used as an electron acceptor
What is the mitochondria
Biochemical energy reactors of the cell where most of ATP is produced
What are some important Biochemical events that occurr in the Mitochondria?
Oxydative decarboxylation
TCA cycle
Electron Transport Chain (Respiratory chain)
Oxydative Phosphorylation
B-oxidation
