Wed Sept 13

• Review worksheet covering objectives for cell respiration, after 1st...

• Wrap up enzyme function (as an example of modulating protein function)

• You might remember from last time: 3 D shape of protein is key to function

e1 e2 e3 e4 e5

Threonine Int-

1

Int-

2

Int-

3

Int-

4

Isoleucine

Multi-enzyme pathways & Regulatory Enzymes

• In bacterial cells a multiple enzyme pathway is involved in generating isoleucine from threonine

• Why regulate this?• How could one regulate this, most

efficiently?• Also see fig 3.39

•What is glycolysis and where does it occur?

•How many ATP are produced (gross) by glycolysis for each glucose molecule that is metabolized?

•How many are used up?

•What is the net ATP production for this set of reactions?

• What are the electron carrying coenzymes that are modified during glycolysis and what is their relevance to cellular respiration?

• In the presence of oxygen how many of each of the reduced coenzymes are produced (per glucose)?

• With oxygen the carbons from the original glucose exit glycolysis as what molecule?

• How many (per glucose)?

• Without oxygen how many of each of the reduced coenzymes are produced during glycolysis?

─ Without oxygen the carbons from the original glucose exit glycolysis as what molecule?

─ How many?

─ Why are there differences in the end products of glycolysis based on oxygen availability?

• In the presence of oxygen, what molecule or molecules enter the citric acid cycle?

─ What is/are the molecular precursor(s) of this/these molecule(s)?

• Where in the cell does the citric acid cycle occur?

•For every glucose that began glycolysis...

─...how many of each type of reduced coenzyme is produced during the citric acid cycle?

─...how many of what waste products are produced?

─...how many ATP are produced from the Krebs cycle?

• How is ATP produced by electron transport/oxidative phosphorylation?

─ Does glucose go straight into this process?

─ What is the role of reduced coenzyme?

─ What is the role/inter-relationship of/between proton pumping/matrix/intermembrane space/proton gradient/diffusion of protons/ATP synthase?

http://www.wiley.com/legacy/college/boyer/0470003790/animations/electron_transport/electron_transport.htm

• For every glucose that starts glycolysis, how many ATP are produced by electron transport/oxidative phosphorylation?

─Note:

NADH = 3 ATP

FADH2 = 2 ATP

Oxygen is used to form H2O

Prior steps yielded 10 NADH + H+ & 2 FADH2 / glucose

To Summarize Energy Production per mole glucose (Aerobic)

• Cytosolic 2 NADH + H+ 2 ATP

• Mitochondrial

─Branch Point 2 NADH + H+

─Citric Acid Cycle 6 NADH + H+ 2 ATP

2 FADH2

─Oxidatative Phos. 34 ATP

• Total: 38 ATP

• The metabolism of a certain triglyceride (storage fat) produces glycerol and three fatty acids for a total of 28 acetyl-CoA molecules. In the presence of oxygen, how many ATP will be produced from this triglyceride?

• Pantothenic acid is one of the B-complex vitamins and as such is one of many essential nutrients required for normal functioning of our metabolic processes.

─A) What is an essential nutrient?

─B) In terms of cellular respiration, what is the importance of pantothenic acid?