Cellular Respiration Flashcards
What is cellular respiration?
A series of chemical reactions that breaks down glucose to release energy
The energy is stored in ATP
Takes place in all cells
What is the formula for cellular respiration?
C6H12O6 + O2 ——> CO2 + H2O + ATP
How is cellular respiration different than a combustion reaction?
It has the same format as a combustion reaction but is different because:
- it’s a slower reaction
- the energy is released in steps
- the energy released is stored in ATP
How efficient is the process of cellular respiration?
The process is only 36% efficient. The other 64% is released as heat
What are the four stages of Cellular Respiration and where do they occur?
- Glycolysis (in the cytoplasm)
- Pyruvate Oxidation (in the mitochondrion)
- Krebs Cycle (in the matrix)
- Electron Transport Chain and Chemiosmosis (inner membrane)
What happens in the process of Glycolysis?
Takes place in the cytoplasm
A 6-Carbon glucose molecule is split into two molecules of pyruvate (a 3-carbon molecule)
An anaerobic process
2 ATP molecules are produced (net)
Glucose is oxidized
NAD+ is reduced
NADH molecules are also produced
What happens to the products of glycolysis?
Pyruvate enters the next phase of cellular respiration (pyruvate oxidation)
NADH is used in chemiosmosis and electron transport
ATP is used by the cell, metabolic processes
What happens in Pyruvate Oxidation?
Before the Krebs Cycle begins, pyruvate is modified
This takes place in the mitochondria
One carbon is lost (in the form of CO2) to form an acetyl molecule
Acetyl joins to a carrier called coenzyme A to form acetyl Co-A
NADH form
What happens in the Krebs Cycle?
Takes place in the matrix of the mitochondria
Starts with Acetyl-CoA
2 carbons enter as acetyl-CoA
Carbons leave as CO2
NAD+ are reduced to form NADH (3 times)
FAD is reduced to form FADH2
ATP is formed
What happens in the Electron Transport Chain?
The inner membrane of the mitochondria contains proteins that carry electrons
They take electrons from NADH and FADH2 that are produced in glycolysis and the Krebs Cycle. These molecules are recycled
As electrons move a small amount of energy is released as they are passed from protein to protein
This energy is used to move H+ into the inter-membrane space
Oxygen is the final electron acceptor
It is reduced to form water
2H + 1/2 O2 + 2e- ——> H2O
What happens to the Electron Transport Chain is there is no O2?
The lack of oxygen causes the system to back up all the way to glycolysis because the NADH and FADH2 can’t be recycled
Hence why if we don’t take in O2, no ATP = cells die = you die
What happens in Chemiosmosis?
A process that produces most of the ATP for cellular respiration
32 ATP are produced per glucose in Chemiosmosis
What does Chemiosmosis require?
A concentration gradient of H+ ions
An ATP Synthase channel which is found in the inner membrane
The ETC causes H+ to build up in the inter-membrane space
H+ ions are not allowed back into the matrix
The ATP Synthase channel is the only place permeable to H+
As H+ flow back into the matrix from the inter-membrane space energy is released
This energy is used to make ATP
What is the total amount of ATP produced in cellular respiration?
2 ATP from glycolysis
2 ATP from Krebs
32 ATP from ETC and Chemiosmosis
TOTAL: 36 ATP per glucose
What is Anaerobic Respiration?
Refers to respiration without oxygen
Without oxygen, NADH and FADH2 cannot get rid of their electrons
This means there is no NAD+ for glycolysis for Krebs Cycle
When oxygen levels decrease NADH and FADH2 give their electrons to another acceptor instead of oxygen
This allows NAD+ and FAD to be available for glycolysis (which produces a small amount of ATP)
