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?
- BMR
- What is not taken into account in BMR?
- activity level
- What percentage of oxygen is used in generating energy for essential life acvitities?
- 90%
-
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?
- 0.2-.06
- 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?
- 90%
- 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?
- No
- 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?
- H2O
- What is the byproduct of glycolysis of glycolysis and the Kreb cycle?
- CO2
- 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?
- 8 NADH
- What is the net yield of ATP per molecule of glucose?
- 30 ATP
- What is the total yield of pyruvate per molecule of glucose?
- 2
- What is the net yield of NADHper glucose?
- 2 NADH
- 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?
- NH3
- 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?
- electrons
- 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?
- 90%
- 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