Ch. 9: Metabolism Flashcards
What is the most common source of fuel in cells?
Glucose
What are the 5 principles of metabolic pathways?
- Complex transformations occur in a series of separate reactions
- Each reaction is catalyzed by a specific enzyme
- Many metabolic pathways are similar in all organisms
- In eukaryotes, metabolic pathways are compartmentalized in specific organelles
- Key enzymes in each pathway can be inhibited or activated to alter the rate of the pathway
3 catabolic processes that harvest energy from glucose
- Glycolysis
- Cellular respiration
- Fermentation
In glycolysis, 1 glucose produces:
2 ATP & 2 pyruvate
After glycolysis and the Krebs Cycle (Citric Acid Cycle), how much ATP, NADH, CO2, ans FADH2 do we have?
6 CO2
8 NADH
2 FADH2
4 ATP
Where does the Krebs (citric acid) cycle take place?
The mitochondrial matrix (inner core of the mitochondria)
What is oxidative phosphorylation?
The electron transport chain and chemiosmosis
Where does oxidative phosphorylation take place?
In/on the inner membrane of the mitochondria
How does oxidative phosphorylation form ATP?
It separates protons from FADH2 and NADH, using the energy of the proton gradient to attach P to ADP, thus producing ATP.
How much total ATP can you get from one glucose using aerobic respiration?
30-32 ATP
When no oxygen is present, what process do cells follow?
Fermentation (lactic acid or alcohol)
In lactic acid fermentation, what does pyruvate do?
Pyruvate is the electron acceptor, and lactate is the product.
What is the lactate threshold?
Point at which production exceeds removal in blood
In alcoholic fermentation, what does pyruvate do?
Pyruvate gets converted to ethanol, releasing CO2 along the way.
As far as catabolic interconversions go, what do polysaccharides break down into and what stage of metabolism do they enter?
Glucose, entering glycolysis
As far as catabolic interconversions go, what do lipids break down into and what stage of metabolism do they enter?
Glycerol for glycolysis and fatty acids (which turn into acetyl coA) for the citric acid cycle
As far as catabolic interconversions go, what do proteins break down into and what stage of metabolism do they enter?
Amino acids, entering either glycolysis or the citric acid cycle (but not the best use of proteins, as we know)
What is gluconeogenesis?
Glucose formed from citric acid cycle and glycolysis intermediates
(Anabolic reactions are just reverse catabolic reactions)
(i.e. acetyl coA can be used to make fatty acids)
Are catabolic reactions reversible?
Yes, most of them are
If 100 molecules of glucose are fermented, what is the approximate net yield of ATP molecules?
200 ATP molecules
Is glycolysis aerobic or anaerobic?
Anaerobic
Is cellular respiration aerobic or anaerobic?
Aerobic (though some microorganisms have developed anaerobic respiration, which uses small molecules or ions as electron acceptors instead of O2)
Is fermentation aerobic or anaerobic?
Anaerobic
In the redox equation below, which is reduced and which is oxidized? Identify the oxidizing and reducing agents.
Na + Cl —> Na+ + Cl- (or NaCl)
Na is oxidized, making it the reducing agent, because it gives away its electron.
Cl is reduced (see the reduction in the charge), making it the oxidizing agent, because it gained an electron.
