Energy Metabolism (Topic 2) Flashcards
Why does ATP have high energy? (2)
it is unstable
Why is ATP unstable? (2)
it has many negative charges that repel eachother
Why is ATP a good energy transferer? (2)
it wants to be broken due to its instability
What is the difference between ATP and GTP? (4)
Their base
ATP = adenine
GTP = guanine
What do NADH and FADH2 do? What are they? (4)
- they carry electrons
- they are coenzymes
What are three energy transfer molecules (not ATP)? (4)
- GTP
- NADH
- FADH2
How do we get ATP? (5)
Carbs go through glycolysis, come out as pyruvate that goes through the Krebs cycle, comes out as coenzyme and goes through oxidative phosphorylation
What are the parts of the mitochondria? (6)
- outside membrane (outer membrane)
- inside membrane (inner membrane)
- space between membranes (intermembrane space)
- space in the middle (matrix)
What is the location of ATP synthesis? (6)
Mitochondria
Where does the Krebs cycle happen? (6)
matrix
Where does electron transport chain and oxidative phosphorylation happen? (6)
inner membrane
What is the difference between combustion and cellular respiration? (6)
glucose + oxygen -> CO2 + water + ATP
- combustion is all in one step (really fast)
- cellular respiration is many many small steps and regulated by enzymes
Where does glycolysis occur? (8)
cytosol
In what conditions can glycolysis occur? (8)
aerobic or anaerobic conditions
What happens in glycolysis step 1-4? (8)
glucose -> glucose 6-phosphate (hexokinase) -> fructose 6-phosphate (phosphohexoseisomerase) -> fructose 1,6-biphosphate (phosphofructokinase)
Why is step 1-4 of glycolysis called the energy investment phase? (8)
because it uses ATP
What happens in glycolysis steps 4-10? (9)
- fructose 1,6-biphosphate splits
- into two 3 carbon intermediates
- then NADH is formed from NAD+
- phosphate group gets removed and added to an ADP to make ATP (phosphoglycerate kinase) (2 ATP made)
- blah
- PEP (3C) is made
- ADP to ATP; PEP to pyruvate kinase (3C) (2 ATP made)
Why is step 4-10 of glycolysis called the energy payoff phase? (9)
ATP is synthesized
What is the reaction of glycolysis? (10)
1 glucose (6C) -> 2 pyruvate (3C) + water + energy
Is oxygen a reactant in glycolysis? (10)
no
Is CO2 produced in glycolysis? (10)
no
How much ATP is produced in glycolysis? (10)
2 ATP produced
Are coenzymes reduced in glycolysis? (10)
yes, 2NAD+ ->2 NADH
What happens after glycolysis? (11)
lactic acid fermentation (anaerobic)
What happens after glycolysis? (11)
lactic acid fermentation (anaerobic)
What is the purpose of fermentation? (11)
during fermentation oxidizes 2NADH -> 2NAD+
- this is beneficial so you can use NAD+ for glycolysis (so glycolysis can keep going)
Is oxidation of pyruvate anerobic or aerobic? (12)
Anaerobic
Does the Krebs cycle occur under anaerobic or aerobic conditions? (12)
aerobic (but doesn’t use oxygen directly)
Why is the Krebs cycle a cycle and not a pathway? (14)
The intermediates get regenerated (you can start anywhere on the cycle)
What important enzymes are in the Krebs cycle? (14)
Oxaloacetate (4C)
Acetyl CoA (2C)
Citrate (6C)
6C intermediate
alpha-Ketoglutarate (5C)
4C intermediate
How many ATP form from each cycle of the Krebs cycle? (16)
1 ATP
How often does the Krebs cycle go through a cycle? (16)
Once per Acetyl CoA (once per pyruvate) (twice per glucose)
What is all produced in the Krebs Cycle? (16)
Acetyla-CoA + 2H2O -> 2CO2 + CoA +ATP + 3NADH + FADH2
3 NADH and 1 FADH2 and 1 ATP
Is CO2 produced in the Krebs cycle? (16)
yes
After the Krebs cycle, where are the 6 carbons from glucose and where is the potential energy from glucose? (14)
- The 6 carbons are now all CO2 molecules (Glucose has been completely oxidized to CO2)
- the potential energy is now many coenzymes (NADH and FADH2) and a little ATP
What is the point of Oxidative phosphorylation?
For taking the energy from the coenzymes and making them into ATP.
What is substrate-level phosphorylation? (17)
The transfer of phosphate group to ADP from phosphorylated intermediate (pyruvate kinase)
What does pyruvate kinase do? (17)
phosphorylates ATP
- Transfers phosphate group from ADP to make ATP
Is oxidative phosphorylation high or low energy? (18)
High (where you get most of your ATP)
What step do you get the most ATP? (18)
Oxidative phosphorylation
What are the products of oxidative phosphorylation? (18)
- water
- NAD+
- 3 ATP from NADH
- FAD+
- 2 ATP from FADH2
How much ATP do you get from NADH? FADH2? (18)
- 3 ATP from NADH
- 2 ATP from FADH2
Why does NADH give more ATP than FADH2? (18)
NADH goes through complex I-IV and FADH2 goes through complex II-IV
- There is more potential energy in complex 1 than complex 2
- (NADH allows for the movement of more protons)
What is the final electron acceptor? (18)
oxygen
What is the function of the electron transport chain? (18)
Electrons are ‘transported’ from one enzyme in the chain to the next. (creates proton gradient)
Why do humans need oxygen? (20)
It is the final electron acceptor in the electron transport chain (without it, everything comes to a stop)
Why is the proton gradient important? (20)
it keeps ATP synthase running
Which way do protons flow in ATP synthase? (21)
Flow up toward matrix and away from intermembrane space
What does the flow of protons cause? (21)
As they flow through, protons cause rotor to turn (similar to water and a turbine)
Why is the change in shape of catalytic units important? (21)
They change shapes that encourage the formation of ATP
What changes the shape if catalytic units? (21)
The turning of the rotor by protons
What is the direct causes (step by step) of a lack of oxygen? (21)
ETC stops, no more protein gradient, ATP synthase cant work (depends on a flow of protons)
What causes proton flow? (20)
Proton gradient
Practice slide 23. (Glycolysis to Krebs to oxidative phosphorylation)
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