Cellular Respiration Flashcards
What are a few differences between cellular respiration and photosynthesis?
- Resp breaks down molecules to capture energy
- Resp uses energy stored in chemicals e.g. proteins, fats and proteins
- Gets rid of electrons by giving them to oxygen
What is the definition of cellular respiration?
A metabolic pathway that releases energy from food, using oxidation and reduction reactions catalysed by enzymes.
What is NAD/NADH?
It’s a coenzyme that is continually reduced and oxidised to move electrons around.
What is FAD?
Carries electrons as two hydrogen atoms and is reduced to FADH2
How do we obtain energy from ATP?
By breaking the last two phosphate bonds in ATP using ATPase
How many ATP molecules are produced in the breakdown of one molecule of glucose?
36
What are the three steps of cellular respiration?
- Glycolysis
- Krebs cycle/TCA cycle
- Electron Transport Chain/ Oxidative Phosphorylation
How many ATP molecules are produced in glycolysis?
2
How many ATP molecules are produced in Krebs?
2
How many ATP molecules are produced in the Electron Transport Chain?
34
Where does glycolysis happen?
Cytoplasm
Where does Krebs and ETC happen?
Mitochondria
Krebs- matrix
ETC- cristae
What happens in Glycolysis?
Glucose (six carbon molecule) is split into two 3 carbon sugar phosphate molecules by hydrolysis of 2ATP into 2ADP+2P.
They are then converted into two pyruvate molecules (3 carbon) by the reduction of 2NAD+ into 2NADH and the substrate level phosphorylation of 2ADP+2P into 2ATP.
What are the outputs of Glycolysis?
2 Pyruvate + 2 ATP and 2NADH
What are the outputs of Glycolysis?
2 Pyruvate + 2 ATP and 2NADH.
What do we achieve from one turn in the Krebs cycle?
3 molecules of NAD+ reduced to NADH
1 molecule of FAD reduced to FADH2
What has to occur before the Krebs cycle?
The oxidation of pyruvate into Acetyl CoA. Pyruvates carboxyl group is fully oxidised is given off as a carbon dioxide molecule. NAD+ is reduced to NADH due to extracted electrons are transferred and stored energy in the form of NADH.
What happens during the Krebs cycle?
Two carbons enter the Krebs cycle from Acetyl CoA and adds the two carbon acetyl group to oxaloacetate to form a 6 carbon molecule - Citrate. Look at diagram drawn in notebook
What happens if the reduced electron carriers in the Krebs cycle are reoxidised without oxygen present?
Fermentation but oxidative phosphorylation if oxygen is present.
What happens during the electron transport chain?
NADH and FADH2 contain energised electrons from Krebs cycle, NADH carry their electrons to the inner mitochondrial membrane where they transfer them to membrane bound proteins. As the electrons are passed down the chain, NADH and FADH2 are oxidised.
What is the final acceptor in the ETC?
Oxygen, an NADH molecule donates two hydrogen atoms to oxygen and it forms water.
How is an electrochemical gradient made?
Protons (hydrogen ions) are pumped into the intermembrane space, forming a high chemical gradient outside the matrix. Protons are driven back into the matrix and have to bypass ATP synthase molecules that drives the oxidative phosphorylation of ATP.
Why does anaerobic respiration not produce as much ATP?
Sugars are not completely oxidised
What oxidation of other molecules gives the highest yield of ATP?
Fatty acids. Net yield is 106 ATP.
