Bioenergetics
The application of thermodynamic principles to organisms and biological systems
- The fundamental characteristics of all living things is the ability to carry out metabolism
What is necessary for life to exist?
Metabolic processes; without them, life would not exist
Releasing chemical energy for an equation that adds Glucose and oxygen gas, what happens?
- The carbons of glucose are oxidized to CO2, with a loss of electrons
- O2 is reduced to 2 H20, a gain of electrons
- energy is made
What are the 4 parts to cellular respiration? Where do they happen?
1) Glycolysis (Breakdown of Glucose) = In cytosol
2) Breakdown of Pyruvate = Mitochondria Matrix
3) Krebs cycle = Mitochondria Matrix
4) Electron transport chain = Mitochondria Inner Membrane
What happens in Glycolysis?
6 Carbon Glucose is broken down to two 3 Carbon Pyruvate
What is used in the process of Glycolysis?
2NAD+ –> 2NADH + 2H+
2ADP + 2P –> 2ATP
What are the 3 phases of Glycolysis?
1) The energy activation/investment phase
2) Cleavage phase
3) Energy liberation phase
Explain what happens in Glycolysis
1) Glucose turns into Fructose -1,6-bisphosphate using 2 ATP
2) Fructose -1,6-bisphosphate (breaks in half) turns into two molecules of glyceraldehyde-3-phosphate
3) two molecules of glyceraldehyde-3-phosphate turn into two molecules of pyruvate, each molecules produces 2 ATP and 1NADH
What happens during the investment stage?
ATP is invested to make Glucose more energetic, we invest a little ATP to get alot later
What makes a favorable reaction +(delta)G or -(delta)G?
-(delta)G which is exergonic in the energy recovery stage
In the investment stage, is the reaction endergonic or exergonic?
Endergonic +(delta)G because the energy is increasing
What happens by the end of Glycolysis? What is the produced result?
- NADH (2molecules)
- Pyruvate (2molecules)
- ATP (put in 2, 4 back)
How does Glycolysis make ATP?
By Substrate Level Phosphorylation
Substrate Level Phosphorylation
The production of ATP by phosphate transfer from substrate to ADP
What does the Breakdown of Pyruvate require?
It requires a transport protein
Explain what happens during the breakdown of Pyruvate?
** Everything is duplicated because there are two pyruvates***
Pyruvate turns into Acetyl-CoA by
1) Pyruvate goes from the cytosol, through the Transport protein, into the mitochondrial matrix
2) Releasing CO2
3) Adding a NAD+ to make NADH+ + H+ (Pyruvate loses 2 electrons)
4) Adding Coenzyme A
5) Makes Acetyl-CoA
Addition of ____ makes the molecule more reactive like phosphorylating Glucose as a bonus it also produces _____
Addition of CoA makes the molecule more reactive like phosphorylating Glucose as a bonus it also produces NADH
Is pyruvate reactant?
No it isnt very reactant
Who got the nobel prize in Medicine in 1953 for The Citric Acid Cycle/ Krebs’ Cycle?
Sir Hans Krebs, and Fritz Lipmann (for Coenzyme A)
Explain The Citric Acid Cycle/ Krebs’ Cycle
** Everything is duplicated because there are two pyruvates, which lead to two Acetyl-CoA**
1) Acetyl-CoA comes in, and releases CoA
2) 2 CO2 are released
3) 3 NAD+ come in, and release 3 NADH+ + 3H+
4) ADP+ Pi comes in, releases ATP
5) FAD comes in, and releases FADH2
Which two things are not produced in the The Citric Acid Cycle/ Krebs’ Cycle?
No ATP or O2
What is the Energy conversion by the end of the Krebs’ cycle?
IN: 1 Glucose & 2 ATP to start glycolysis
OUT: 6 ATP (4 in glycolysis, 2 in Krebs cycle)
10 NADH
2 FADH2
6 CO2
What happens after The Citric Acid Cycle/ Krebs’ Cycle?
Oxidative Phosphorylation or the Electron Transport Chain
Mitochondrial Electron Transport:
What are the 5 structures?
Complex I, Complex II, Complex, III, Complex IV, ATP synthase
Mitochondrial Electron Transport:
What happens in Complex I?
1) H+ pass from the mitochondrial matrix to the inner compartment
2) NADH is added, passes an e- through the complex, and releases NAD+
Mitochondrial Electron Transport:
What happens in Complex II?
FADH2 is added, passes an e- thought the complex, and releases FAD
Mitochondrial Electron Transport:
What happens in Complex III?
The e- from complex I and the e- from complex II pass through the Complex III
Mitochondrial Electron Transport:
What happens in Complex IV?
1) H+ pass from the mitochondrial matrix to the inner compartment
2) The 2e- from Complex III are added (2e- + 2H+ + 1/2 O2) OR (2e- + 4H+ + O2), releases an H2O or (2 H2O)
Mitochondrial Electron Transport:
What happens in ATP Synthase (ATPase)
3 H+ are passed from the intermembrane compartment the mitochondrial matrix to produce 1 ATP from ADP+ Pi
What is the name of the transport protein between Complex I& III? Complex III & IV?
CoQ
Cytochrome c or cyt c
Where does the energy come from when the ATP synthase makes ATP?
The energy comes from the concentration gradient, which is converted to the chemical energy of ATP (Chemiosmotic Theory)
Who won the nobel prize in chemistry in 1978 for the chemiosmotic theory?
Peter Mitchell
What happens to the energy in the electron transport?
Each step loses energy to entropy, but energy is also banked by the production of the H+ gradient
- the electron flow decreases and we move across complexes
In cellular respiration, how many ATP are made?
Varies, but from 30-38 ATP usually 36 ATP
Anaerobiosis:
Strict Anaerobes
Organisms that are unable to live in the presence of oxygen
EX. Clostridium tetani or botulinum
Anaerobiosis:
Facultative Anaerobes
Organisms can live in both Oxygenic and Non-oxygenic environments EX. Saccharomyces cerevisiea - with O2 = osidative phosphorylation - no O2 = fermentation (beer) EX. Ecoli
Explain the Alcoholic Fermentation cycle in the absence of O2
Yeast Ferment Glucose into Ethanol
1) Glucose makes 2 pyruvic acid through glycolysis
- 2ADP + 2P go in, produces 2ATP
- 2 NAD + go in, produce 2NADH
2) 2 Pyruvic acid makes 2 Ethanol
- 2 CO2 are released
- 2 NADH + 2H+ go in, produces 2 NAD+
How many ATP are produced in the Alcoholic Fermentation cycle in the absence of O2? Why?
Only 2 ATP are produced because the Electron Transport Chain is blocked
What is different in the Lactic Acid Fermentation compared to the Alcoholic Fermentation?
1) 2 Pyruvic acid is turned into 2 Lactic Acid instead of 2 Ethanol
2) In this process there is no CO2 released
3) IT is Anaerobic respiration
During Anaerobic respiration, muscle O2 depletion leads to _______________
Lactic Acid Production
How many ATP are produced in the Lactic Acid Fermentation?
2 ATP are produced, no CO2 released
Where does the Lactic Acid Fermentation occur?
In muscle tissue, also in making cheese & yogurt
How do muscle respire?
Both aerobically (with O2) & anaerobically (without O2)
Under high power demand the muscles will be _______
Anaerobic
Under low-demand, sufficient O2 reaches the muscle ________ to use _____________
Under low-demand, sufficient O2 reaches the muscle mitochondria to use Oxidative Phosphorylation
Anaerobic Threshold
The point where your body will supplement aerobic metabolism with anaerobic fermentation
Muscle cells adapt to exercise, making more _________ and using ____ more efficiently
Muscle cells adapt to exercise, making more mitochondria and using O2 more efficiently
- Can’t run 100 m in 10s without using anaerobic muscles
Under anaerobic conditions, the cell ____________
Under anaerobic conditions, the cell “ferments” glucose
__________build up increases the ______of the cell, which also hinders muscle function
Lactic Acid build up increases the acidity of the cell, which also hinders muscle function
How is Lactic Acid converted back to Glucose?
This happens in the liver through gluconeogenesis, however it requires large amounts of ATP, which is supplied by oxidative phosphorylation (oxygen debt)
- Aerobically
Lactic Acid convertion to Glucose
________ is the reserve of Glycolysis
__________ is made into _________
This requires ______ & ______
Gluconeogenesis is the reserve of Glycolysis
Pyruuvate is made into Glucose
This requires ATP & NADH
*VIEW SLIDE 34**
Explain how creatine is made
Phosphocreatine (amino acid) + ADP + Pi Creatine + ATP
_____________ can run out of ATP
_____________ can supply ATP
Fast-twitch muscle cells can run out of ATP
Phosphocreatine can supply ATP
Creatine:
__________ is used up very rapidly during muscle contraction
____________ can then regenerate ATP for a short time
Cellular ATP is used up very rapidly during muscle contraction
Phosphocreatine can then regenerate ATP for a short time
Can Creatine be accumulated?
No cells can’t accumulate creatine
VIEW SLIDE 36
Fast-twitch/ Slow twitch muscle amounts are __________ controlled
A gene called _______ can alter muscle type ratios
Fast-twitch/ Slow twitch muscle amounts are genetically controlled
A gene called PPAR(O) can alter muscle type ratios
Greater __________ muscle ratio yields better exercise endurance
Loss of the PPAR(O) gene makes endurance better/worse
Greater Slow-twitch muscle ratio yields better exercise endurance
Loss of the PPAR(O) gene makes endurance worse
What does the Uncoupling protein do?
It allows sm hibernating animals (rodents) to short-circuit the H+ gradient to generate heat
What does short-circuiting the H+ gradient do to the cycles?
It increases the rates of glycolysis and Krebs cycle to produce the NADH used
Respiratory Poisons:
Rotenone
Used to kill insects and fish
- produce a lil ATP then die
Respiratory Poisons:
Cyanide
Similar effect to rotenone
- Stop O2 from reacting
Respiratory Poisons:
Oligomycin
Blocks the ATP Synthase
- A fungicide
Respiratory Poisons:
Dinitrophenol (DNP_
An uncoupler
- Short-circuits the ETC
- Picks up H+ ions and diffuses them across the membrane, lets them go
- NO ATP saved
Breakdown of Foods:
________ is not a common energy source in out food
Each food type can be broken down to produce ______________
Free glucose is not a common energy source in out food
Each food type can be broken down to produce cellular energy
**DOESNT have to go in a straight line
Where can proteins begin to breakdown? Carbohydrates? Fats?
Proteins (amino acids) = Glycolysis OR Acetyl CoA or Citric Acid cycle
Carbohydrates (Sugars) = Glycolysis
Fats (Glycerol) = Glycolysis
Fats (Fatty acids) = Acetyl-CoA