6.7-6.10 & 6.12 Flashcards
Glycolysis means
splitting of sugar
How many carbon atoms per pyruvate?
3 carbons
What is gained from glycolysis, though not necessarily part of the products?
Two pyruvate, two ATP (net gain) and two NADH.
What is substrate-level phosphorylation?
An enzyme that creates ATP and three-carbon chain with phosphate as products. A substrate with a high-energy bond releases chemical energy when it’s converted to a lower-energy product
Where does the energy come from in glycolysis, and where does it go to?
The oxidation of glucose to pyruvate (which still holds most of glucose energy), stored in NADH and ATP
What is the difference of energy usage in NADH and ATP?
ATP can be used immediately, NADH must send electrons down electron transport chain.
How many chemical reactions in glycolysis?
9
What is an intermediate?
things that are formed before the products, that help make the products.
What is the energy investment phase of glycolysis?
Where two ATP molecules are use to energize the glucose, making fructose 1,6 biphosphate.
What is the energy payoff phase in glycolysis?
Starts with the splitting of the fructose biphoshate into two glyceraldehyde 3-phosphate. G3P is oxidized by NAD.+ After a phosphate is lost, making (2) ATP molecules through substrate level phosphorylation. Then the final phosphate is again used for ATP after some rearranging. Water is a by-product. Left with two pyruvate molecules.
The ATP molecules from glycolysis are __ % of the energy that can be harvested from glucose.
6
What does NADH need to function?
Oxygen – or else would go to fermentation
For each glucose molecule processed, what are the net molecular products of glycolysis?
Two molecules of pyruvate, two molecules of ATP, and two molecules of NADH.
Why is pyruvate oxidized?
in preparation for the citric acid cycle.
Where does glycolysis take place?
The cytosol.
How does this “grooming” of pyruvate work to set it up for the citric acid cycle?
A multi-enzyme complex catalyzes three reactions: (1) removes carboxyl (-COO-) group, released as CO2. (2) Electron (H-) is removed from the now two-carbon complex and added to NAD+ to make NADH. (3) Coenzyme A joins with the two-carbon group to form acetyl CoA
What is the citric acid cycle also called?
The Krebs Cycle, TCA cycle
What is the overview of the krebs cycle?
“A metabolic furnace hat oxidizes the acetyl CoA derived from pyruvate.”
Of acetyl CoA, what enters the “cycle”?
The two-carbon acetyl, CoA is recycled.
What does the two-carbon acetyl bond with? What does it create?
It bonds with the energy-poor oxaloacetate and forms 6-carbon citrate.
What are the 5 and 4 carbon molecules in the citric acid cycle (in order). Not high priority
citrate (6) - NADH is reduced, CO2 leaves cycle, alpha-ketoglutarate (5), NADH is reduced, CO2 leaves cycle, ATP is phosphorylated, (4) succinate, FAD is reduced to FADH2, (4) Fumerate, H20 is added (4) Malate, NADH is reduced, back to (4) oxaloacetate.
How is the ATP molecule made in the citric acid cycle?
substrate-level phosphorylation ( a process where a phosphate group is directly transferred from a high-energy substrate to ADP or GDP, forming ATP or GTP, without the involvement of electron transport chains or ATP synthase. )
Per molecule of glucose what (important) molecules are produced in the citric acid cycle? overall?
2 ATP, 6 NADH, 2FADH2.
4 ATP, 10 NADH, 2 FADH2.
How is the energy from the NADH and FADH2 harvested? What is the energy used for.
“Shuttle” their high-energy electrons down the electron transport chain; oxidize themselves. It is used to create an H+ gradient in the intermembrane space.
what does the suffix -ate mean?
a molecule is in its ionized form.
What is the total number of NADH and FADH2 molecules generated during the complete breakdown of one glucose molecule to six molecules of CO2?
10 NADH: 2 from glycolysis, 2 from the oxidization of pyruvate, 6 from the citric acid cycle; and 2 FADH2 from the citric acid cycle.
Brief overview of oxidative phosphorylation:
Electron carriers built into a membrane makes it possible to create a H+ concentration gradient across the membrane and then use the energy of that gradient to drive ATP synthesis.
How does oxygen (1/2O2), the final electron acceptor, form water at the end of the ETC?
Accepting two electrons and picking up 2 H+.
What is the link reaction?
Another name for Acetyl CoA reaction.
How many proteins are involved in the ETC?
Four
What do three of those four proteins do (not including the second one)?
Bring H+ ions into the intermembrane space, building up a higher concentration for the enzyme ATP synthase to use.
Chemiosmosis and ATP synthase analogy can be a:
Dam/waterwheel.
What turns the wheel of ATP synthase?
Protons.
Fun fact about ATP synthase:
It is the smallest rotary motor known to man.
How much ATP is produced per spin of the rotary motor from a proton?
Depends.
What effect would an absence of oxygen (O2) have on the process illustrated in the ECT and protein complex?
Without oxygen to “pull” electrons down the electron transport chain, the energy stored in NADH and FADH2 could not be harnessed for ATP synthesis.
Final review of what is produced each step of cellular respiration:
glycolysis: in cytosol: 2 ATP and 2 NADH (2 pyruvate). Link reaction: 2 NADH, 2 acetyl CoA. Citric acid cycle: 6 NADH and 2 FADH2 and 2 ATP (s-l phosphorylation). FADH2 and NADH pump H+ ions that which with ATP synthase make approximately(!!) 28 ATP. Total ATP yield is 32.
Why is the number of ATP produced not approximate?
FADH2 adds its electrons to the chain later and contributes less, H+ gradient can be used for other work such as movement of pyruvate to mitochondrion.
Oxygen is necessary to be the final electron acceptor in cellular respiration. Is it possible to produce ATP without oxygen?
Yes.
Explain where O2 is and CO2 is produced in cellular respiration.
O2 accepts electrons at the end of the electron transport chain. CO2 is released during the oxidation of intermediate compounds in pyruvate oxidation and the citric acid cycle.
