Cellular Respiration Flashcards
Priming
2 ATP gets reacted with glucose, resulting in a 6 carbon diphosphate (F6P) and 2 ADP + 2 Pi
Cleavage
6 carbon molecules w/ 2 phosphate splits into 2, forming 2 three-carbon sugar phosphates
Phosphorylation/Harvest
2 pyruvates are formed in a series of reactions involving NAD+ and ADP, which results in the products (4 ATP and 2 NADH) of glycolysis
REACTANTS of glycolysis
6 Glucose, 2 ATP, 2 NAD+, 2 ADP + 2 Pi
PRODUCTS of glycolysis
2 pyruvate, 2 ATP (net), 2 NADH, 2 H+, 2 ADP
LOCATION of Pyruvate oxidation
Matrix
STEPS of pyruvate oxidation
2 pyruvate molecules release 2 CO2 molecules (decarboxylation)
NAD+ is reduced to NADH
Addition of Coenzyme-A
Produces Acetyl-CoA
REACTANTS of pyruvate oxidation
2 pyruvate molecules, NAD+, Coenzyme A
PRODUCTS of Pyruvate oxidation
2CO2, NADH, Acetyl-CoA
- when ATP conc’n is high,
Acetyl-CoA can be used to make fat for energy storage
- when ATP conc’n is low,
Acetyl-CoA can be used to make ATP
Krebs cycle LOCATION:
matrix
Krebs cycle purpose
to break down acetyl-CoA
STEPS of krebs cycle
Acetyl-CoA reacts with Oxaloacetate and produces citrate and CoA as by-product
Releases 3 NADH + 3 H, 1 FADH2, 1 ATP and 2 CO2 in its steps and eventually come full circle to make oxaloacetate again
REACTANTS of krebs cycle
Oxaloacetate, Acetyl-CoA, ADP + Pi, 3 NAD+, FAD
PRODUCTS of Krebs cycle
Oxaloacetate, Co A, ATP, 3 NADH + 3 H+, 2 CO2, FADH2
EXTRA Krebs cycle
2 cycles for every 1 molecules of glucose
Oxaloacetate + Acetyl-CoA + ADP + Pi + 3 NAD+ + FAD → Oxaloacetate + CoA + ATP + 3NADH + 3H+ + 2CO2 + FADH2
ETC Location
Cristae (flap folds in membrane)
PURPOSE of ETC:
to transfer energy to an electrochemical gradient by pumping H+ ions into an intermembrane space
STEPS of ETC
NADH start the ETC by donating electrons to protein complex 1.
Electrons move through the chain, reducing and oxidizing the next protein complex
Each protein complex is alternately reduced (by gaining two electrons from the component before it) and oxidized (by losing two electrons to the component after it)
Each next electron acceptor is more stable than the last (until you reach oxygen, the most electronegative), meaning that energy is released in each part of the chain
The free energy created by the electrons moving from one protein complex to the other is used to move the H+ ions in the mitochondrial matrix to the inner membrane space
Creates electrochemical gradient
REACTANTS ETC
NADH, FADH2, 2H+ + ½ O2
PRODUCTS ETC
NAD+, FAD, H2O
Chemiosmosis Location
Cristae
Chemiosmosis PURPOSE:
a process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme
Chemiosmosis STEPS:
The protons from the intermembrane space must pass through the ATP synthase to diffuse through (cannot go through bilayer)
The free energy stored in the gradient produces a proton-motive force (PMF) that moves protons through and ATPase complex
This energy drives the synthesis of ATP from ADP and an inorganic phosphate in the matrix
ATP made by chemiosmosis exits the cell by facilitated diffusion to power endergonic processes of the human body (i.e. movement, active transport, synthesis reactions, etc.)
Chemiosmosis REACTANTS:
ADP + Pi
Chemiosmosis PRODUCTS:
ATP
ATP yield is usually lower b/c:
Protons can leak through the inner mitochondrial membrane w/o passing through the ATP synthase complex
Some energy is used to transport ATP out of the mitochondria for use in the cytoplasm
What are uncouplers?
An agent that dissociates the phosphorylation that occurs in electron transport.
How do they interfere with ATP production
This prevents the formation of ATP.
Allows H+ ions to go through the membrane without doing anything
A coupled reaction: endergonic (i.e. proton down concentration gradient needs to be coupled to ATP formation. An uncoupler separates these two–ADP+Pi and proton)
Dangers of DNP as a weight loss pill
It stops the mitochondria in your cells from absorbing the energy that has just been released from your body breaking down your food. That energy needs to go somewhere. So it becomes heat.
Anaerobic respiration
Metabolic pathway in which an inorganic molecule (other than oxygen) is used as the final electron acceptor during chemiosmosis
AKA when oxygen is not available, the body kicks into anaerobic respiration
Alcoholic fermentation
A form of fermentation occurring in yeast in which NADH passes its hydrogen atoms to acetaldehyde, generating CO2, ethanol, and NAD+
Alcoholic fermentation main steps
Glucose breaks down into pyruvate
Pyruvate is decarboxylated forming acetaldehyde
2 CO2 is released
NADH passes its H+ ions to acetaldehyde, regenerating NAD+
Ethanol is formed
Alcoholic fermentation PURPOSE
A form of fermentation occurring in yeast in which NADH passes it hydrogen atoms to acetaldehyde, generating CO2, ethanol, and NAD+
Alcoholic fermentation Reactants
2 pyruvate, 2 ADP + P, 2 NAD+, 2 Acetaldehyde
Alcoholic fermentation Products
2 Acetaldehyde, 2 CO2, 2 Ethanol, 2 ATP, 2 NADH + H+
Lactic acid fermentation
A form of fermentation occurring in animal cells in which NADH transfers its H atoms to pyruvate, regenerating NAD+ and lactate
Lactic acid fermentation Main steps
Glucose is converted into pyruvate
NADH transfers its H atoms to pyruvate
Pyruvate is converted into lactate
Lactic acid fermentation Purpose
a form of fermentation occurring in animal cells in which NADH transfers its H atoms to pyruvate, regenerating NAD+, and producing lactic acid.
Lactic acid fermentation Reactants
2 pyruvate, 2 ADP + 2 P, NAD+
Lactic acid fermentation Products
2 Lactate, 2 ATP, 2 NADH + 2 H+
Thermodynamics
1st Law
the total amount of energy in the universe is constant
Energy cannot be created or destroyed but only converted from one form into another
If an object or process gains an amount of energy, it does so at the expense of a loss in energy somewhere else in the universe
2nd law
The entropy of the universe increases w/ any change that occurs
What is entropy?
A measure of the randomness or disorder in a collection of objects or energy
In a chemical reaction, entropy increases when:
Solid → liquid or gas
Liquid → gas
Few moles of reactant create a greater # of moles of product molecules
Complex to simple molecules (polymers → monomers) (glucose → CO2 + H2O)
Diffusion
What is free energy?
Energy that can do useful work
Gibbs Free Energy (delta G) = enthalpy (delta H) - temperature x entropy (delta S)
Is cellular respiration spontaneous? why or or why not? Is it exergonic or endergonic?
Cellular respiration is spontaneous because it is an exergonic reaction. More energy is released during bonding formation than absorbed during breaking bonds. This means that there is a decrease in enthalpy (delta H) and an increase in entropy (delta S, which is favoured).
Is photosynthesis spontaneous
Photosynthesis is not spontaneous because it’s endothermic and a has decrease in entropy
