Cellular Respiration Flashcards
Cellular Respiration
The process of converting stored chemical energy to usable energy in the form of ATP.
-ATP can be broken down to release energy when a phosphate is removed, creating ADP and Pi
Each time there is an energy change, some energy is lost as heat.
-not all of the energy stored in ATP is used to do work in the body
Anaerobic Respiration
-No oxygen
-Produces 2 ATP from glycolysis
-Called alcoholic fermentation in yeast cells
Called lactic acid fermentation in muscle cells and bacteria
Alcoholic Fermentation
-Cytoplasm of yeast cells
-Products of Glucose breakdown: CO2 and ethanol(C2H5OH)
-Net ATP yield: 2
-used in making alcohol
-causes bread dough to rise
Lactic Acid Fermentation
-Cytoplasm of muscle cells, bacteria
-Products of Glucose breakdown: Lactic acid/lactate (C3H6O3)
-Net ATP yield: 2
-results in muscle cramps and fatigue
-making yogurt and cheese
Aerobic Respiration
-Uses oxygen
Produces 36 ATP per glucose
Glycolysis+O2—>Kerbs cycle —>
ETC/Oxidative phosphorylation
Phosphorylation
Addition of a high energy phosphate molecule to a substance.
-Oxidative phosphorylation - the energy comes from oxidation reactions
-Photophosphorylation - the energy comes from light
Sources of energy for ATP production
-Glucose - most usable source
-Once glucose is depleted:
- Glycogen(storage form of glucose in animals)
- Fat
- Protein
Glycolysis
-Anaerobic process which happens in the cytoplasm
-Purpose - split glucose to create pyruvate(pyruvic acid)
-Pyruvate molecules now have 2 possible fates:
-if O2 is not present -fermentation
-if O2 is present - kerbs cycle
Final result from glycolysis
-Net gain of 2 ATP
- 4 ATP produced, 2 used up
-2 NADH
-2 pyruvate
-Most energy following glycolysis is still stored in the Pyruvate molecules, break down in kerbs
The Kerbs Cycle
-Aerobic process within the mitochondrial matrix
-Pyruvate diffuses across the mitochondria membranes
-Purpose - transform the energy from pyruvate into reducing power of NADH and FADH2
-NADH and FADH2 will then be used in the ETC to create ATP
Net result from Kerbs cycle
From each glucose molecule (2 Pyruvates):
- 8 NADH
- 2 FADH2
- 2 ATP
Electron Transport Chain & Chemiosmosis / Oxidative Phorphorylation
- Occurs along the folded inner membrane of the mitochondria
- the folds in the membrane(cristae) allow the chain to be repeated many times
- electrons are passed along a series of proteins called the electron transport chain - Uses the energy stored in NADH and FADH2 to cause ADP+Pi —> ATP
-oxidative phosphorylation
-Produces most of the ATP in an animal cell
-Following the Kerbs cycle, the matrix has 8 NADH and 2 FADH2 per glucose molecule
NADH
-NADH is oxidized by the first protein in the ETC
- The protein accepts its electron and “pumps” its H+ from the matrix to the intermembrane space
- As the electron is passed from one protein to the next, 2 more H+ are pumped out of the matrix
FADH2
-FADH3 is oxidized by the second protein in the chain (CoQ)
- Only 2 H+ are pumped across because the first protein was skipped
H+ gradient
-Eventually, protons (H+) are concentrated in the intermembrane space, and very few are left in the matrix
- creates a concentration gradient
Chemiosmosis hypothesis
- A proton concentration gradient is created across the inner membrane by the pump proteins
- ATP is made when the protons flow back through the membrane through a special channel
- The channels are an enzyme called ATP synthase, which creates ATP
The role of oxygen in ETC and chemiosmosis
-Oxygen is the final electron acceptor in the ETC
- It accepts electrons and H+ ions, creating water
-Without O2, the ETC will stop, causing the Kerbs cycle to stop due to a lack of FAD and NAD+
