AP Biology Study Sheet for Chapters 6 & 9 Exam

The transformation of the energy from glucose into ATP happens in three steps.
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain (Oxidative Phosphorylation)

The Krebs Cycle and Electron Transport Chain are together known as “Respiration” or more properly “Aerobic Respiration” since oxygen is needed to make them happen.
Glycolysis is known as an anaerobic process since oxygen is not specifically needed for it to occur; pyruvic acid can be made any day of the week without any oxygen around. But without oxygen around living things run into a problem- not because they produce too much pyruvic acid- but because they deplete NAD and since this is absolutely needed to keep glycolysis going, it comes to a grinding halt and the cell has no way to make any ATP. Without ATP the cell dies. This is remedied by either alcohol fermentation or lactic acid fermentation, both of which are anaerobic processes (see the end of this sheet for what you need to know about this).

Glycolysis
Do not:
•Memorize the chemical names except for glucose and pyruvic acid
Do:
•Know how many chemicals there are and how many carbons they have
•Realize where the process has to be run twice for each glucose
•Know how many ATP’s and NADH’s are produced and where this occurs (generally)
•Know the enzyme that controls glycolysis and how it works ****Super important!
•Where glycolysis occurs in the cell

The Bridge
•Memorize it completely and know where it occurs in the cell

Krebs Cycle (Also known as the Citric Acid Cycle)
Do not:
•Memorize the chemical names except for acetyl- Coenzyme A, oxaloacetic acid and citric acid (because these are the three that start the process)
Do:
•Know that there are a number of chemicals in the pathway and that during the cycle a 6 carbon molecule (citric acid) is broken down into a 4 carbon molecule (oxaloacetic acid)- releasing 2 carbon molecules in the form of CO₂
•Understand that this is where most of the CO₂ is being generated in the cell.
•Know how many ATP’s, NADH’s, FADH₂’s are produced and where this occurs (generally)
•Realize the cycle has to be run twice for each glucose
•Where the Krebs Cycle occurs in the cell

Electron Transport Chain (Oxidative Phosphorylation)
Do Not:
•Memorize the chemical names in the chain except to know that four of them are cytochromes.
Do:
•Know the basic function of the electron transport chain
•Know what molecule is the final acceptor of electrons
•Know how many ATP’s are produced for each NADH and FADH₂
•Know where the electron transport chain occurs in the cell

Mechanism that explains oxidative phosphorylation
Do Not:
•Attempt to memorize the picture of electrons shuttling back and forth within the inner mitochondrial membrane
Do:
•Know they name of this theory and why it has its name
•Understand how the architecture of the mitochondria is uniquely designed for this process to work
•Explain conceptually how energy is transferred from NADH to ATP in this theory.
•Explain the importance of being able to create a hydrogen gradient
•Explain the role of ATP synthetase

Energy Harvest
Do:
•Know how many ATP’s, NADH’s, FADH₂’s, are produced and where.
•Be able to explain clearly where all the 36 ATP’s come from.
•Explain why there are not 38 ATP’s

Anaerobic Respiration
Do:
•Memorize the two equations
•Understand why these processes occur
__________________________________________________________________
Make sure you know the overall equation for this entire process:
glucose + oxygen = carbon dioxide + water + energy (now stored in ATP)

Remember: Energy is never created nor destroyed so it has to go somewhere. A lot of it goes into heat (that’s why you are a nice warm 37^o C or 98.6^o F), but the rest is transferred into ATP molecules ready to do chemical work in the cell.
Disclaimer: There may be material on the test from Chapter 9 that has not been mentioned here; this sheet was produced to help streamline your studying.