Aerobic Respiration and Fermentation

glucose is getting oxidized

oxygen is reduced

each electron transfer is

exergonic

what drives ATP synthesis

released free energy from electron transfer (electrons in H2O have less potential energy than they did in glucose

energy from glucose ____ released at once

energy from glucose IS NOT released at once

NAD+ does ____

important electron acceptor (gets reduced) during cellular respiration

cellular respiration is a cumilative of four steps

1. glycolysis

2. pruyvate oxidation and citric acid cycle (oxidation of carbon and salvaging of high energy e-)

3. oxidative phosphorylation (electron transport/ATP synthesis)

glycolysis

• sugar splitting

  • 6 carbon sugar (glucose) to 2× 3 carbon sugar (pyruvate)

• occurs in the cytosol

glycolysis steps

1. priming the pump (add two ATP) energy investment phase

2. cleavage, rearrangement and energy release (4 ATP molecules + NADH)

   

substrate level phosphorylation

in glycolysis ATP is generated by the transfer of a phosphate group from a phosphorolayted substrate to ADP to make ATP

pyruvate kinase

in the final step of glycolysis it phosphorolyates to make pyruvate

at the end of glycolysis

• no O₂ was used

• no C fully oxidized to CO₂

• 2 ATP molecules were made

how efficent is glycolysis?

very efficent, it only makes two molecules, but it is very fast

why is glycolysis not enough

glycolysis requires a continues supply of NAD⁺ to keep operating, but NAD⁺ is limited in cells

fermentation

• absence of oxygen

• allows glycolysis to continue by regenerating NAD⁺

• aerobic respiration occurs in the matrix

• two types

  • lactate

  • alcoholic

lactate fermentation

• pyruvate is reduced, NADH is oxidized, and lactate and NAD⁺ is formed

alcholic fermentation

pyruvate is converted into acetaldehyde and carbon dioxide

1. first step relases for CO₂

2. second step creates ethanol

intermediate complex

Recall that, in some chemical reactions, enzymes may bind to several substrates that react with each other on the enzyme, forming an intermediate complex. An intermediate complex is a temporary structure, and it allows one of the substrates (such as ATP) and reactants to more readily react with each other;

if there is not enough pyruvate kinase what will happen?

The last step in glycolysis will not occur if pyruvate kinase, the enzyme that catalyzes the formation of pyruvate, is not available in sufficient quantities. In this situation, the entire glycolysis pathway will proceed, but only two ATP molecules will be made in the second half. Thus, pyruvate kinase is a rate-limiting enzyme for glycolysis.

which processes create CO₂

electron transport

citric acid cycle

alcholic fermentation

Describe the redox reaction that happens as electrons leave the NADH and jump onto Complex I

NADH is oxidized

Complex 1 is reduced

How does the potential energy of electrons change as they move through the ETC?

potential energy decreases

each complex is more electronegative

elctrons have the least amount of potential energy when with oxygen

Which results in higher ATP production: NADH or FADH₂?

NADH