Cellular respiration Flashcards
Luft syndrome
Over active mitochondria. Lots of oxygen being used, little ATP being produced.
Diseases the mitochondria effects
ALS, Parkinson’s, Alzheimer’s, Huntington’s disease
Mitochondria
Key reactions of cellular respiration occur here. Energy from food molecules is taken and used
Cellular respiration
Collection of metabolic reactions that break down food molecules and use the free energy to make ATP
Biosynthetic reactions
AKA anabolic reactions.
Production of carbohydrates
In photosynthesis light energy extracts electrons from water. The electrons connect CO2 and H+ to make glucose
Carbohydrates make
Proteins and fats with their energy
Biproducts of photosynthesis
Oxygen. Which is needed for cellular respiration. A continual cycle
What are carbohydrates good fuel
An abundance of C—H bonded molecules
C—H bonds
High energy because their electrons are held equally between the two atomic nuclei loosely. Easily removable to do work
C—O bonds
More electronegative, so lower potential energy because electrons are being held tighter to oxygen
Why fats are more Kcal
Only made of C—H bonds so more energy is produced
Oxidized
Losing an electron and becoming more positive
Reduced
Gaining an electron and becoming more negative
Redox reactions
The complimentary processes of oxidation and reduction happening
Redox reaction basis
Xe- + Y —- X + Ye-
Oxidation name
Many fuels oxidized involve oxygen as the molecule that gains electrons and gets reduced
Oxygen in reactions
Car engines, oil fires and cellular respiration
Redox problems
Not all reactions involve oxygen
Electrons can be transferred completely of incompletely
Incomplete electron transfer
A shift in how much an electron is shared between 2 atoms
Redox of glucose
Through combustion energy is released as electrons to oxygen, reducing water. Carbon is oxidized to CO2
Glucose activation energy
High. A flame or enzyme-catalyst can be used to each a small activation energy. The thermodynamics are the same
Difference in glucose activation energy
A flame creates a large amount of sudden heat, controlled combustion creates small amounts of usable energy
Dehydrogenases
Enzymes that facilitate electrons from food to an energy carrying molecule (shuttle)
Nicotinamide adenine dinucleus
NAD+ oxidized, NADH reduced
NADH
A coenzyme and the most common energy carrier. Removes 2 H+ and returns 2 electrons and one proton. Highly efficient
Main job of cellular respiration
Turn potential energy in food into ATP, glucose goes through all the steps and therefore is our focus
Phases of CR
Glycolysis, pyruvate oxidation and citric acid cycle, oxidative phosphorylate
Glycolysis
Glucose and enzyme— 2 pyruvate +some ATP + some NADH
Pyruvate oxidation and citric acid cycle
Pyruvate oxidation—acetyl coenzyme A which is oxidized into CO2. Some ATP and NADH is formed
Oxidative phosphorylate
NADH is oxidized from electrons traveling down the electron transport chain until oxygen turn’s into H2O. Free energy creates a proton gradient used to make ATP
Archaea and bacteria
Glycolysis and citric acid cycle in the cytosol, oxidative phosphorylation occurs in the internal membrane
Eucharyotes
Step 2 and 3 take place in the mitochondria
Glycolysis in detail
10 enzyme catalyzed reactions leading to the oxidation of 6 carbon glucose. Produces 2 pyruvate molecules, ATP and NADH.
Experiment discovering glycolysis
100 years ago they proved you can do reactions in an isolated, cell free environment. The foundation of biochem
Glycolysis is ancient because
- It is universal between bacteria, archaea, and eukaryotes
- It does not need oxygen (life existed before oxygen did)
- Occurs in the cytosol. Not requiring complex, evolved organelles
3 concepts of glycolysis
Energy investment followed by pay off
No carbon is lost
ATP is generated by substrate level phosphorylation
Energy investment followed by payoff
Has two phases. Energy requiring and energy releasing
Energy requiring phase
5 steps. 2 ATP’s used by glucose and fructose. 6-phosphated becomes phosphorlated
Energy returning phase
4 ATP and 2 NADH are produced
No carbon is lost
Glucose (6 carbons) becomes 2 pyruvate (3 carbons). Oxidation has occurred as the potential energy of pyruvate is less than the glucose
ATP is generated by substrate level phosphorylation
A phosphate group is transferred from a high energy substrate to ADP making ATP used in the citric acid cycle
Pyruvate oxidation and the citric acid cycle
Extraction of remaining free energy and trapping it in ATP and electron carriers
Pyruvate movement
Cytosol to outer MM through simple diffusion to the inner MM passes using a pyruvate specific membrane carrier into the mitochondrial matrix
Pyruvate oxidation
Multistep process where pyruvate becomes acetyl-CoA
Step 1-Decarboxlation reaction
Carboxyl (COO-) is removed from pyruvate and becomes co2
Step 2-Acitate production
The oxidation of the 2-carbon molecules produces acetate
Step 3-Dehydrogenation reaction
2 electrons and a proton are transferred to NAD+ making NADH
Step 4-CoA
Acetyl group reacts with CoA forming high energy acetyl CoA
Citric acid cycle
C-H bonds exist in acetyl CoA, here they are broken and the energy is used. 8 enzyme catalyzed reactions.
Reactions 1-7
Soluble enzymes in the mitochondrial matrix
Reaction 8
Bound to the matrix side of the inner membrane. Is insoluable
Citric acid cycle overall
The acetyl group is oxidized, ATP, NADH, and FAD are made
FAD
Nucleotide base molecule flavin adenine dinucleotide. Reduced to FADH2
1 turn of the citric acid cycle
3 NADH, 1 FADH2, 1 ATP, 2 CO2 is made from 1 acetyl unit. All of the C is now CO2