Chapter 5 - Cell Respiration and Metabolism

What is metabolism

the sum of all the chemical reactions in the body

includes all the reactions in the body that involve energy transformation

What are the two categories that metabolism can be divided into?

Anabolism & Catabolism

Anabolism

• Reactions that require the input of energy

• Synthesis (building) reactions of large energy-storage molecules including glycogen, fat, and protein

Catabolism

• Reactions that generally release energy

• Reactions that break down glucose, fatty acids, and amino acids to provide primary sources of energy for the synthesis of ATP

What does energy transfer involve?

Oxidation - reduction reactions

Oxidation

is when a molecule loses electrons

Reduction

is when a molecule gains electrons

The final electron acceptor in the breakdown of glucose in cell respiration is:

Oxygen and we create Water

What is the overall aerobic respiration of glucose equation? What does it yield?

C₆H₁₂O₆ + 6O₂ —→ 6CO₂ + 6H₂O

Will yield about 30 ATP

What are the four steps in Aerobic Cell Respiration

1) Glycolysis

2) Acetyl CoA production

3) Citric Acid Cycle

4) Electron-Transport System

How does oxygen change the products of glycolysis?

The products of glycolysis can either enter anaerobic metabolism when oxygen is not available or can enter aerobic cell respiration when there is oxygen available

A

Capillary

B

Interstitial fluid

C

Plasma membrane

D

Cytoplasm

E

Mitochondrion

What are election carriers?

NAD and FAD are carriers that transport electrons to the electron transport system

Where does much of the Aerobic Cell respiration occur?

In the Mitochondrion

What form is NAD in?

Oxidized (Not carrying e-)

What form is NADH in?

Reduced (carrying e-)

What are intermediate carriers?

NAD and FADH2

These take electrons to the electron transport system

What does NAD do?

NAD is a coenzyme that transfers pairs of hydrogen atoms from one molecule to another

Does Glycolysis need oxygen?

It both does and doesnt need oxygen

Where does glycolysis occur?

In the cytoplasm of the cell

How much ATP does Glycolysis need of input?

Requires 2 ATP of input energy

End products of glycolysis

2 pyruvate

2 NADH

2 ATP

What happens when there is low oxygen availability during anerobic metabolism?

Pyruvate will turn into lactate

What is a somewhat normal occurrence in skeletal muscles or in red blood cells that lack mitochondria?

Low oxygen availability leads to pyruvate to turn into lactate during anerobic metabolism

When and what is pyruvate converted into?

During step 2 of cell respiration pyruvate is converted to acetyl CoA.

This occurs in the mitochondrial matrix

Where does Acetyl CoA production take place?

Starts in the cytoplasm and ends in the mitochondrial matrix

What is the starting and end products of Acetyl CoA production

Starting:

2 pyruvate

End:

2 Acetyl - CoA

2 CO2

2 NADH

What does the citric acid cycle ensure?

That many electrons can be transferred to the electron transport system

Where does the citric acid cycle occur?

mitochondrial matrix

How many turns are there per glucose during the citric acid cycle

2 turns

What are the total end products after 2 turns of the citric acid cycle

2 ATP

6 NADH

2 FADH2

4 CO2

What occurs during the electron transport chain?

Oxidative phosphorylation

Where is the electron transport system located?

in the inner mitochondrial membrane

How does NADH and FADH2 become oxidized?

By transferring their pairs of electrons to the electron transport system

Describe the Electron Transport Chain

Electrons are dropped of by ??? and ???.

Electrons are passed along the molecules in the chain. Eventually the electrons attract H+ and create a proton (H+) gradient

This “fuels” ATP synthase to create ATP from ADP where H+ re-enters the mitochondrial matrix.

The electrons are then added to molecular oxygen (O2) to form water

What is considered the final electron acceptor

Oxygen

Final product of the electron transport chain

30 ATP

6 H2O