C9

Cellular Respiration and Fermentation

Is the breakdown of organic molecules endergonic or exergonic?

exergonic

Aerobic respiration

consumes organic molecules and O2 and yields ATP

Fermentation

partial degradation of sugars that occurs without O2

redox reaction/oxidation-reduction reactions

chemical reactions that transfer electrons between reactants

oxidation

substance loses electrons, or is oxidized

reduction

substance gains electrons or is reduced(amount of positive charge reduced)

What happens in some redox reactions?

some do not transfer electrons but change the electron sharing in covalent bonds

What is an excellent source of high-energy electrons?

organic molecules with an abundance of hydrogen

Glycolysis

“sugar splitting”) breaks down glucose into two molecules of pyruvate

Where does glycolysis occur and what are its two major phases?

Energy investment phase, energy payoff phase

does it matter if O2 is present in glycolysis

no it will occur either way

What happens after pyruvate is oxidized?

citric acid cycle completes the energy-yielding oxidation of organic molecules(in presence of )2, pyruvate enters a mitochondrion(in eukaryotic cells)

Where do pyruvate oxidations and the citric acid cycle take place?

the matrix of the mitochondrion

What does the citric acid cycle do?

completes breakdown of pyruvate to Co2 and oxidizes organic fuel derived from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn

A small amount of ATP is formed in glycolysis and the citric acid cycle by_

substrate-level phosphorylation

The process that generates almost 90% of the ATP is called_____because it is powered by redox reactions

oxidative phosphorylation

where is the electron transport chain?

in the inner membrane(cristae) of the mitochondrion

what is the flow of the ETC?

1. electrons are transferrred from NADH or FADH2 to the electron transport chain,2. electrons are passed through a number of proteins and finally to O2, 3.the ETC generates no ATP directly(it creates a H+ gradient)

What is chemiosmosis?

the energy coupling mechanism

the energy released as electrons are passed down the electron transport chain is used to

pump H+ from the mitochondrial matrix to the intermembrane space

H+ then moves down its concentration gradient back across the membrane, passing through the protein complex__

ATP synthase

Sequence of Cellular respiratation

glucose—→ NADH(or FADH2)——>electron transport chain——→prton-movtie force——→ATP

what happens in an aerobic reaction?

glucose is oxidized and oxygen is reduced

how much energy in a glucose molecule is transferred to ATP during cellular respiration and how much ATP is made?

34% and it makes 32 ATP, rest of energy is lost as heat

What does most cellular respiration depend on?

electronegative oxygen to pull electrons down the transport chain

what would happen without oxygen?

ETC would cease to operate.

in lack of oxygen what happens?

glycolysis couples with anaerobic respiration or fermentation

what does fermentation consist of?

glycolysis plus reactions that regenerate NAD+ which can be reused by glycolysis

two common types of fermentation?

alcohol and lactic acid

fermentation vs cellular respiration(NADH to NAD +)

in fermentation, an organic molecules(pyruvate or acetaldehyde) acts as a final electron acceptor

in cellular respiration, electrons are transferred to the electron transport chain

fermentation vs cellular respiration(ATP)

cellular respiration produces 32 ATP per glucose

Fermentation produces 2 ATP per glucose