Lecture 9 - Energetics Flashcards
What is glycolysis? Where does it occur
First step to breaking down glucose
Cytosol
Glycolysis forms… (net)
2 pyruvate, 2 ATP, and 2 NADH
How many ATP does glycolysis use? Produce?
Uses 2, produces 4
End product of glycolysis
Pyruvate
Citric acid cycle aka… Where does it occur?
Krebs/TCA
In the mitochondria
What does the CAC produce per 1 pyruvate
1 ATP or GTP
3 NADH
1 FADH2
2 CO2
Pyruvate becomes what to enter the CAC? What happens in this reaction
Acetyl CoA
An NADH and CO2 are released
Where do the electron transport chain and oxidative phosphorylation occur? Their roles?
In the membrane of mitochondria
Create electron gradient that can be used to generate ATP through ox phos
Each NADH that enters the ETC provides how many ATP? FADH2?
1 NADH = 3 ATP
1 FADH2 = 2 ATP
How many NADH and FADH2 are produced through glycolysis and the CAC? Equal to how much ATP?
10 NADH per glucose
2 FADH2 per glucose
= 34 ATP
Slide 7*
confused. 42 or 38 ATP??
How much ATP is generated when one acetate enters the CAC
Generate 12, but -2 when acetate is converted to acetyl-CoA so = 10
How do you make acetyl CoA
Acetate + Coenzyme A requires 2 ATP
Conversion of propionate so it can enter the CAC? Requires? Produces?
Can be converted to phosphoenolpyruvate
Requires 3 ATP, 1 GTP
Produces 1 GTP, 1 FADH 2, 1 NADH
How does phosphoenolpyruvate enter the CAC
Converted to pyruvate (produces 1 ATP)
The oxidation of propionate generates how many ATP? Net?
22 ATP
but 4 required
= 18 ATP/propionate
How does fatty acid metabolism generate ATP
Beta-oxidation of C-C
Beta-oxidation of palmitate to 8 acetyl CoA generates how much ATP? These acetyl CoA enter the CAC to generate how many?
35 ATP
96 ATP from CAC
How much ATP is generated by beta-oxidation of palmitate (16C)? Net?
131 ATP
but 2 ATP required
= 129 ATP/palmitate
How are non-esterified fatty acids mobilized from adipose tissue
Hormone-sensitize lipase stimulates their release
Bound to albumin, circulates in blood
Taken up by liver
What happens to NEFAs in the liver
Re-esterified and stored as triglycerides
Incorporated into lipoprotein (VLDL)
Beta-oxidation to make acetyl CoA
Two methods of beta-oxidation of NEFAs in the liver
Complete oxidation (used as an E source)
Incomplete oxidation (pre-digestion of fatty acids): synthesize ketone bodies (B-hydroxybutyrate, acetone)
Characteristics of ketone bodies
Water soluble
Decrease lipolysis rate
Normal fuel in muscles
In order to utilize ketone bodies (acetoacetate) by making them into acetyl CoA, what needs to occur
They cannot be in the liver, need to go to other tissues
Conversion of acetoacetate to acetyl CoA
Acetoacetate -> acetoacetyl CoA -> 2 Acetyl CoA
Slides 19, 20
Utilization of ketone bodies
What is ketosis
Negative energy balance generated in a post absorptive state, particularly starvation from mobilized fatty acids
Mobilized f.a. go to liver, undergo incomplete b-oxidation into ketones, circulate in body
Liver has limited capacity to oxidize f.a.
What else can enter the kreb’s cycle?
Amino acids, enter into different parts of the cycle based on their structure
Glucogenic vs ketogenic aa
Glucogenic enter kreb’s cycle to make ATP
Ketogenic enter the process of generating ketones, become Acetyl CoA or acetoacetyl CoA
What are bomb calorimeters used for
Know how much energy we get out of a diet
What is metabolizable energy
Digestible energy - energy in urine and gas
What is digestible energy
Gross energy - energy in feces
Slide 26
Summary
What is direct calorimetry
Direct measurement of heat: feed energy - fecal energy - urinary energy
What is indirect calorimetry?
Based on biochemical principles and known combustion values (e.g. glucose + O2 -> CO2 + H2O at a different proportion than fat)
Measurements of indirect calorimetry
CO2 produced
O2 consumed
Respiratory quotient (RQ = CO2/O2)
Urinary N (protein oxidation)
Reaction of glucose to gasses when completely combusted
C6H12O6 + 6O2 -> 6CO2 + 6H2O + 672 Kcal
RQ of glucose completely combusted
6CO2 produced / 6O2 consumed = 1
How much energy per L of O2 consumed if only glucose is oxidized in the body
5.0 Kcal/L
Slides 28-> 32
Confusing
