Topic 7: catabolic pathways

catabolic pathways

metabolic pathways that release stored energy by breaking down complex molecules

fermentation

degradation of organic fuel without using oxygen

aerobic respiration

degradation of organic fuel using oxygen, like in cellular respiration

what does the term fuel involve?

carbohydrates, fats, proteins, and molecules

what do catabolic pathways do?

transfers electrons from fuel molecules ti other molecules

what is cellular respiration?

an aerobic process, involving the degradation of glucose into CO2

energy from catabolism is captured in…

the bonds of ATP

oxidation

loss of electrons (electron donor and reducing agent)

reduction

gain of electrons (electron acceptor, oxidizing agent)

what is a redox reaction?

when electrons are transferred between two substances

electrons lose potential energy when…

they love a less electronegative atom to a more electronegative atom

What is NAD+?

Coenzyme that carries electrons from one molecule to another, reduced to NADH

Substrate level phosphorylation

Phosphate group is transferred from a substrate to ADP to make ATP. Where ATP is produced in glycolysis and the citric acid cycle

glycolysis

glucose is split into two 3-carbon sugars which are oxidized to make two molecules of pyruvate

what happens in the energy investment phase?

ATP is used

what happens in the energy payoff phase?

ATP is produced by substrate level phosphorylation and NAD+ is reduced to NADH

what is the energy gained by glycolysis?

2 ATP and 2 NADH

for glucose to break down we have to…

get it to a higher energy level

what is pyruvate oxidation?

pyruvate enters the mitochondria in eukaryotes

what are the three steps to pyruvate oxidation

1. carboxyl group is removed-release of CO2

2. Oxidation of carbon to form acetate

3. Coenzyme A is attached to acetate to form acetyl CoA, which is made of Vitamin B

what happens in the citric acid cycle?

acetylene CoA is oxidized to Co2

How much ATP does glycolysis and the citric acid cycle produce?

4 ATP molecules pee glucose molecule

describe oxidative phosphorylation

most energy is still tied up in the electrons carried by NADH and FADH2. this energy is released through ETC and chemiosmosis

What is the electron transport chain?

molecules in a membrane. NADH shuts electrons to the starting molecule of the ETC