(15) Krebs Cycle

Where does the Krebs Cycle take place?

the mitochondria

How many carbons in pyruvate?

3

Dehydrogenase

enzyme involved in the movement of electrons on molecules

multimeric protein

protein consisting of multiple peptide chains (quaternary structure protein)

Pyruvate dehydrogenase (structure, role in relation to krebs cycle, how does it affect carbon count)

large multimeric enzyme which takes in multiple substrates and releases multiple products. Before the Krebs cycle begins, it takes pyruvate, NAD+, and coenzyme A and creates acetyl coenzyme A (AcCoA), NADH, and CO2. Two carbons from pyruvate go to AcCoA and one to CO2.

How much CO2 would be made from 3 pyruvate as it is processed and goes through the krebs cycle?

9

Which intermediates of the krebs cycle contain phosphate?

none of them

Draw the Krebs cycle (you only need to know circled enzymes, names and carbon number of each intermediate, and steps that involve electron transfer)

When 1 pyruvate goes through the Krebs cycle, how many pairs of electrons are harvested (ONLY BY THE KREBS CYCLE) ? How many when 3 pyruvates go through? How many when PDH is included?

4;12;5 and 15

How many kilocalories of energy is left in the molecule after a pyruvate goes through the PDH and the krebs cycle?

none, it is completely oxidized (note that pyruvate is a 3 carbon compound and 3 CO2 is produced)

The energy of a pyruvate is either [] or [] after undergoing PDH and the krebs cycle

lost or trapped

t/f krebs cycle applies only to glucose metabolism

false. Some components of the cycle is used in the oxidation of fatty acids or amino acids

Beta oxidation

process in the mitochondria in which 2 carbons are harvested off of a fatty acid at a time to form acetyl coenzyme A (AcCoA) molecules. This may then go into the krebs cycle

How many electron pairs may be harvested from a single 8 carbon fatty acid which undergoes beta oxidation the then krebs cycle

16

How may amino acids be harvested for energy production in the krebs cycle

there are many biochemical pathways which may convert certain amino acids into a certain intermediate of the krebs cycle

t/f the krebs cycle is relatively unregulated and just proceeds at whatever pace is necessary

false, every enzyme of the krebs cycle is tightly regulated

Show the products when one glucose undergoes glycolysis, PDH, then the Krebs cycle

after glycolysis, 2 ATP, 2 NADH and 2 pyruvate is made. These 2 pyruvates then react with PDH, NAD+ and CoA to form 2 NADH, 2 CO2 and 2 AcCoA. Those 2 AcCoA then go through the Krebs cycle to form 4 CO2, 2 GTP, 6 NADH, and 2 FADH.  (Overall: 6 CO2, 2 ATP, 10 NADH, 2 FADH, and 2 GTP)