Chapter 9: Cellular Respiration and Fermentation

What is the energy flow?

Energy is transferred from the sun to plants to animals to make ATP

How does energy leave the flow?

As heat

What happens to chemicals?

They are recycled

What is the formula for cellular respiration?

Glucose + O2 → CO2 + H2O + ATP

What is the goal of cellular respiration?

To make more ATP

How does cellular respiration occur?

Electron transfer

Oxidation

A reaction in which a substance loses electrons

Reduction

A reaction in which a substance gains electrons

What element is a strong oxidizing agent?

Oxygen

During aerobic respiration what compounds are oxidized and reduced?

Glucose is oxidized and oxygen is reduced

What do metabolic reactions rely on?

Electron carriers

Electron carriers

Molecules that easily shift between oxidized and reduced states to transfer electrons

What are the oxidized and reduced states of NAD?

Oxidized is NAD^+ and reduced is NADH

What are the three ways to extract energy from glucose?

Aerobics respiration, anaerobic respiration, and fermentation

What steps are a part of aerobic respiration?

Glycolysis, Karen’s cycle, electron transport chain; oxygen is terminal electron receptor

What are the steps of anaerobic respiration?

Glycolysis, Krebs cycle, electron transport chain; uses non oxygen inorganic molecule as terminal electron acceptor

What are the steps of fermentation?

Glycolysis and organic electron acceptor

What are the three steps of aerobic cellular respiration?

Glycolysis, Krebs cycle/citric acid cycle, oxidative phosphorylation/electron transport chain

Where does glycolysis take place?

In the cytoplasm

What is the reactant in glycolysis

Glucose

What are the products of glycolysis?

2 pyruvate, 2 ATP via substrate level phosphorylation, 2 NADH

Does glycolysis require oxygen?

No, it requires no oxygen

Substrate level phosphorylation

An enzyme used to transfer a phosphate group from a substrate to ADP to make ATP

What must pyruvate become before it enters the Krebs cycle?

Acetyl Cola

What does pyruvate lose to become Acetyl CoA?

A CO2 and some hydrogens, then it binds to Coenzyme A

Where does the Krebs/Citric Acid cycle take place?

In the inner mitochondrial membrane

What is the reactant of the Krebs cycle

Acetyl CoA

What are the products of the Krebs cycle?

6 CO2, 8 NADH, 2FADH2, 2 ATP via substrate level phosphorylation

Electron transport chain

Series of proteins that receive electrons from NADH and FADH2

What happens with electrons in the electron transport chain?

Electrons are transferred to increasingly electronegative proteins

What is happening to energy at each transfer in the electron transport chain?

Energy is released at each transfer

When do electrons finally rest in the electron transport chain?

When they land on oxygen gas (aerobic respiration) or another inorganic molecule (anaerobic respiration)

What is used to make the ATP

Chemiosmosis

What compounds drop off electrons to proteins in the inner mitochondrial membranes to power the formation of ATP?

NADH and FADH2

What are the reactants of the electron transport chain?

NADH, FADH2, O2

What are the products of the electron transport chain?

ATP, H2O

Multiprotein complexes I, III, and IV

Energy from electron transfers is used to pump hydrogen ions out of the mitochondrial matrix into the intermembrane space

Multiprotein complex II

Accepts electrons from FADH2, does NOT pump hydrogen ions across the membrane

Ubiquinone

Mobile electron carrier molecule (non protein)

Cytochrome c

Mobile electron carrier

Cytochrome a3

Gives electrons to oxygen

ATP synthase

Makes 28 ATP through the hydrogen ion gradient (proton motive force)

How do H+ ions flow back into the cell

Along the gradient through ATP synthase; the rotor spins and the knob adds inorganic phosphate to ADP

What is the net yield of cellular respiration?

32 ATP

How much energy from the glucose in cellular respiration is used to make ATP

40%

What happens to the remaining 60% of energy from glucose?

It is lost as heat; this heat is used to maintain body temperature

When does fermentation take place?

In the absence of oxygen

What happens within fermentation?

NAD is recycled, and very little ATP is made

In aerobic respiration

Pyruvate is completely broken down by citric acid cycle, much more nervy is harvested, and about 32 ATP is yielded

In fermentation

Pyruvate is not broken down and is instead converted to a different end product, much less energy is harvested, and about 2 ATP per glucose is yielded