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Introduction to Mitochondria and Energy Generation


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BMR = ? + ?
Body Weight (KG) + 24 kcals/day-kg
What does BMR measure?
The energy required to maintain life
What does measuring the rate of oxygen consumption or heat production by a resting person after an overnight fast give you?
What is not taken into account in BMR?
activity level
What percentage of oxygen is used in generating energy for essential life acvitities?
What percentages above BMR do the following activities contribute to energy consumption:

a. Sedentary
b. Moderate
c. Heavy
a. Sedentary - 30%
b. Moderate - 65%
c. Heavy - 100%
Why is only lean body mass (and not fat tissue) calculated in BMR
because fat is not metabolically active
What is asthenia
weakness... loss of strength
What is the primary problem in Lufts disease?
The mitochondria are unable to adjust their respiratory rate according to the need for energy.
If one's [ADP] goes up and [ATP] goes down, what effect will this have you their energy need?
Given that
Energy = [ADP]/[ATP]
The energy need will increase
What is the equation for respiratory control?
RC =
(oxygen consumption when [ADP]/[ATP] is low)
(oxygen consumption when [ADP]/[ATP] is high)
What will happen to Respiratory control as oxygen consumption is increased?
respiratory control is lessened.
In properly functioning mitochondria, what is the normal R.C. value?
What does respiratory control couple?
R.C. couples energy consumption to energy need
What is the driving force for the aquisition of energy from fuel sources in living things?
the formation of energetically stable endproducts, such that the carbon will be more stable in the form of CO2 and oxygen will be more stable in the form of water
Alice = ?
your future
What happens in stage I of breakdown of food molecules?
large polymeric molecules are brokendown into monomeric subunit:

proteins -> amino acids

polysaccharides --> simple sugars (glucose)

Fats --> fatty acids and glycerol
What happens in stage II of the breakdown of food molecules?
monomeric subunits enter the cytoplasm for futher degradation, e.g., glucose is converted to pyruvate (ATP is produced); glycolysis
What happens in stage III of the breakdown of food molecules?
After entering the mitochondria pyruvate is converted to acetylCoA, where it is completely oxidized to to water and carbon dioxide (along with the production of ATP); TCA cycle and ETC
Why do fats contain more potential energy than sugars or proteins?
sugars and proteins are partially oxidized... fats are in a reduced state
What are the energy yields of the complete oxidation of 1 gram of the following to carbon dioxide?

a. carbohydrate
b. protein
c. fat
a. carbohydrate - 4.2 kcals
b. protein - 4.2 kcals
c. fat - 9.5 kcals
How do you determine Respiratory quotient?

R.Q. = ?
R.Q. = (CO2 expired) ÷ (O2 consumed)
How and why is R.Q. used?
Take a balanced equation and determine the R.Q. using the given oxygen used and carbon dioxide produced. This tells us the type of fuel preferentially used by tissues
What type of fuel source does an R.Q. of the following represent?

a. R.Q. = 1.0
b. R.Q. = .75
c. R.Q. = .7
a. R.Q. = 1.0 --> sugar
b. R.Q. = .75 --> non-protein
c. R.Q. = .7 --> fat
What percentage of energy from fuel is extracted in the mitochondria?
What happens to sperm mitochondria?
It is ubiquinated at the 4-8 cell stage of embryonic development. (This will not happen if the species are different.)
What size molecule can enter the outer membrane of the mitochondria?
MW of 5,000
What makes the inner membrane of the mitochondria impermeable to ions and polar molecules?
cardiolipin, a dimer which accounts for 10% of the inner membrane lipid content
What do you find in the mitochondrial matrix?
Enzymes of the citric cycle, ribosomes, tRNAs, and mitochondrial DNA
Do mitochondrial DNA code for the same amino acids as nuclear DNA and/or the same amino acid in all species?
What are the kcals/g for carbs, protein and fats?
Carbs & protein: 4.2 kcal/g⬦ fats: 9.5 kcals/g
What is the byproduct of oxidative phosphorylation?
What is the byproduct of glycolysis of glycolysis and the Kreb cycle?
which products are yielded from glycolysis?
NADH, ATP and pyruvate
What is the total yield of NADH per molecule of glucose in glycolysis + TCA cycle?
What is the net yield of ATP per molecule of glucose?
30 ATP
What is the total yield of pyruvate per molecule of glucose?
What is the net yield of NADHper glucose?
Give the balanced equation for glycolysis.
2 NAD + 2 ADP + 2 Pi --> 2 pyruvate + 2 NADH + 2 ATP + 2 H2O + 2H+
What is the byproduct of protein metabolism?
Which molecule do protein, carbs and fats converge upon?
acetyl CoA
Give the balanced equation for the Kreb (citric) cycle.
acetyl CoA + 3 NAD + FAD + GDP + Pi + 2 H2O + 1 CoA-Sh--> 2 CoA-Sh + 3 NADH + 3 H+ + FADH2 + GTP + 2CO2 + 1 H2)
What do NADH and FADH2 transport?
Which requires more oxygen to be metabolized, carbs or fats? Why?
fats, since they exist in a less oxidated state
What happens in stage I of fuel metabolism?
basic (large polymeric) fuels like carbs, fats, and proteins are broken down to monomers
In what state do carbs, fats and proteins enter the cell?
carbs: simple sugars⬦ fats: fatty acids (& glycerol)⬦ protein: amino acids
What happens in stage II of fuel metabolism?
fuel monomers are transported into the cell and undergo futher breakdown (eg., glycolysis)
What happens in stage III of fuel metabolism?
The complete Break down of Acetyl-CoA → ATP + H2O + CO2
What is BMR?
The amount of energy (in kcals) required to sustain life (per day) = kcals/day
What is BMR a measurement of?
Rate at which oxygen is consumed or heat given off by a resting person after a night's sleep.
what is the general equation (for a normal individual) for BMR?
BMR (kcals/day)= body weight (kg) x 24 kcals/day/kg
As a percentage of BMR, what is the average energy expenditure for sedentary, moderate and heavy activity
Sedentary: 130% BMR⬦ Moderate: 165% BMR⬦ Heavy: 200% BMR
What percentage of oxygen is used to generate energy?
What is an equivalent way of expressing BMR?
O2-mL/min/kg (lean body mass)
What is respiratory control (R.C) used to measure?
energy usage
What two things does R.C. demonstrate the relationship between?
energy generation and energy need
Energy generation = ?
Energy generation = rate of respriation (O2 consumption)
Energy need = ?
Energy need = [ADP]/[ATP]
R.C. =?
(O2 consumption when the [ADP]/[ATP] is LOW) ÷ ⬦⬦..(O2 consumption when the [ADP]/[ATP] is HIGH)
Give the unbalanced equation for oxidative phosphorylation.
ADP + H+ (NADH and FADH2) + Pi +O2 --> ATP + H2O + (NAD and FAD)
When energy need is high, which concentration should their be higher [ATP] or [ADP]?... 2) Which does the high energy ADP/ATP concentrations effect the numerator or the demoninator of the R.C.?... 3) In normally functioning mitochondria, does a high [ADP
1) [ADP] 2) denominator... 3) small
When energy need is low, which concentration should their be higher [ATP] or [ADP]?... 2) What does the high energy ADP/ATP concentrations effect the numerator or the demoninator of the R.C.?... 3) In normally functioning mitochondria, does a high [ADP]
1) [ATP]... 2) denominator... 3) small
1. What does R.C. stand for?

2. What does it couple?
1. Repriatory control.

2. Energy need to energy generation
Which of the following do R.Q.s of 1.0 and 0.75 coincide with - Liver, Brain, or Muscle?
Brain = 1.0 R.Q.

Liver = .75 R.Q.

Muscle = 0.75 R.Q.
Where in the mitochondria is ATP concentration the greatest?
sites of high ATP utilization
Which have more mitochondria, RBC or Liver cells?
RBCs have zero mitochondria... Liver: 1000-2000 mitochondria
T/F: mitochondria take up a small portion of the cytoplasm?
false, substantial
T/F: Upon fertilization, the human sperm does not deliver mitochondria to the egg.
False, sperm delivers one mitochondria, however it is ubiquinated.
1) What limits the size of molecules permeating the outer mitochondrial membrane?

2) What size molecule (in molecular weight) can enter the outer mitochondrial membrane?
1) Porin

2) 5,000
1) Can ion or polar molecules cross the inner mitochondrial membrane?

2) What regulates entry into the matrix?
1) no

2) cardiolin (made of diphosphotidylglycerol... thus tightly packed)
Give 3 examples of things mitochondrial DNA code for.
m-ribosomes, ATP synthase, mtRNA
What does UGA code for in universal DNA and in mitochondrial DNA?
Mitochondrial UGA = Trp

Universal UGA = Stop codon
Give two examples of disease passed on through mitochondrial DNA
deafness, Alzheimer's

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