ellular respiration and fermentation

ch 9 exam 3

what catalyzes the reactions that govern metabolic processes?

enzymes

why don’t we oxidize glucose in a single step?

the amount of energy released would be far too great for a carrier molecule to capture

what do most cells need to make ATP?

glucose

metabolic pathways harvest energy from

high-energy molecules

What uses solar energy to produce sugars and organic molecules?

photosynthesis

what oxidizes food molecules to obtain chemical bond energy?

Respiration

what is feedback inhibition?

a reaction’s end product inhibits or controls the enzyme’s function that helped make it earlier in the process

what are catabolic pathways?

a series of chemical reactions that breaks down complex larger molecules into smaller simpler ones

what are anabolic pathways?

a series of chemical reactions that builds larger, complex molecules from smaller, simpler ones

anabolic pathways always

requires a net energy input

catabolic pathways always

release energy

cells generally contain enough ATP to sustain how much activity?

from 30 seconds to a few minutes of activity

organisms store glucose as

glycogen or starch

what happens when glucose is oxidized?

some energy is released as heat and light

what happens to the energy released by glucose oxidation?

much of it is used to synthesize ATP

what is fermentation?

an oxygen-free metabolic process that cells use to convert sugars into energy

does fermentation oxidize glucose fully?

no

does cellular respiration or fermentation produce more energy?

cellular respiration

What are the four processes of cellular respiration?

Glycolysis, Pyruvate processing, citric acid cycle, electron transport and oxidate phosphorylation

What is Glycolysis?

A six-carbon glucose is broken down into two three-carbon pyruvate molecules

What happens in Pyruvate processing?

each pyruvate is oxidized to form acetyl CoA

what happens in the citric acid cycle?

each acetyl CoA is oxidized to CO₂

What happens in electron transport and oxidative phosphorylation?

Electrons move through a transport chain and their energy is used to set up a proton gradient, which is used to make ATP

What is cellular respiration?

any set of reactions that uses electrons from high-energy molecules to make ATP

what are two fundamental requirements of cells?

Needs an energy source to generate ATP, and a source of carbon to use as raw materials for synthesizing macromolecules

what are the intermediates of the cellular respiration pathway used for?

energy or for structural materials

What is glycolysis?

a series of 10 chemical reactions that occur in the cytosol

what are the three key points of glycolysis?

1. glycolysis starts by using two ATP in the energy investment phase (1-5)

2. during the energy payoff phase (6-10) NADH is made from ATP is produced by substrate-level phosphorylation

3. the net yield is two NADH, two ATP, and wo pyruvate

What are the three main steps of glycolysis?

investment, cleavage, energy payoff