Major Concepts to Review for AP Biology

Cell Respiration

Cell respiration involves 3 processes

Glycolysis (anaerobic) ------makes 2 ATP's
Fermentation (anaerobic)----returns NAD for use in glycolysis.

Citric Acid cycle -------------uses oxygen to complete oxidation of glucose and make 34 ATP's (includes the electron transport chain and the ATP synthase as part of the F₀F₁ complex

Glycolysis:

uses 2 ATP's
makes 4 ATP's (net of 2 ATP molecules)
converts glucose into 2 pyruvates
makes NADH (necessary for electron transport or for fermentation)
is anaerobic and occurs in the cytoplasm
is found in all living things

Citric acid cycle:

begins when acetyl-CoA combines with a 4-carbon molecule resident within the citric acid cycle (acetyl group + oxaloacetic acid = citric acid)
oxidizes "food" molecules to produce electrons and Hydrogen ions
generates per cycle or one pyruvate the following

2 CO₂
1 ATP	double each per 1 glucose molecule
3 NAPH₂
1 FAD

sends the electrons to the electron transport chain in the inner membrane of the mitochondria.

Electron Transport Chain

uses electrons from oxidation of food molecules
uses proton pumps to generate proton gradient
oxygen acts as the final electron acceptor and is reduced to water

Muscles and Energy

Muscles have lots of mitochondria and need and use lots of ATP
If ATP is used up they can continue because creatine phosphate is a second energy source
glycolysis can supply quick energy and
lactate fermentation recycles needed NAD from NADH creating a oxygen debt.
Being "in shape" decreases the time necessary to pay off an oxygen debt because of:
- enlarged lung capacity
- heart has greater stroke volume
- more blood cells increases oxygen carring capacity
- greater muscle mass and improved vascularization (more capillaries)

Fats and proteins can be used as alternate fuels - hydrolysis and other metabolic steps can turn most molecules into pyruvate or acetyl-CoA

Additional Information may be found at: