5 Energy transfers- Respiration Flashcards
What is the importance of respiration?
It converts energy within the bonds of glucose into a more readily available for: ATP
Where does glycolysis occur?
The Cytoplasm
Is glycolysis aerobic or anaerobic?
Anaerobic
glycolysis occurs in both respirations and types
What occurs during phosphorylation and oxidation in glycolysis?
Phosphorylation- Glucose is phosphorylated to glucose phosphate w/ 1 molecule of ATP. Glucose phosphate is phosphorylated by another ATP molecule to hexose biphosphate (6C), which splits to 2 triose phosphate (TP) molecules
Oxidation- the 2 TPs are oxidised to Pyruvate (3C) A single TP makes 2 ATP and 1 NADH
What is the net gain of glycolysis?
2 ATP molecules (2 used, 2 gained)
2 NADH molecules
2 Pyruvates
What occurs during the link reaction?
Pyruvate is actively transported from cytoplasm across mitochondrial membrane—> mitochondrial matrix. Here, Pyruvate is decarboxylated & dehydrogenated to acetate (2C). CO² is made as a byproduct of-product, NAD reduced to NADH
Acetate combines with coenzyme A to make acetyl coenzyme A
How is citrate made in the Krebs Cycle?
-Acetyl coenzyme A acts as a carrier for the 2C acetyl group.
-It reacts with oxaloacetate (4C) to make citrate (6C). -Coenzyme A is now available to be recycled & reused in the link reaction
How is oxaloacetate regenerated?
-Citrate is converted to a 5C molecule by decarboxylation & dehydrogenation. CO² is made as a by-product and NAD is reduced to NADH
-The 5C is decarboxylated & dehydrogenated again to a 4C compound. CO² is made, NAD is reduced to NADH, ATP made (substrate-level phosphorylation)
-The 4C is dehydrogenated again, NADH & FADH are made
What is the net gain of the Krebs Cycle?
-2 CO² molecules
-3 NADH molecules
-1 ATP molecule
-1 FADH molecule
This is for 1 Pyruvate molecule, but for one glucose molecule this is doubled
Where does oxidative phosphorylation occur and why is it suitable for this?
Inner mitochondrial membrane
Have 3 electron carrier proteins (ETC), ATP synthase
How is a proton gradient formed in oxidative phosphorylation?
-All the NADH, FADH² produced are oxidised by first electron carrier protein in inner mitochondrial membrane.
-The molecules release 2 protons & 2 electrons each.
-The electrons are transferred along the ETC
-As electrons move down ETC, they lose energy.
-The energy pumps protons from NADH/FADH² into intermembrane space. Proton gradient is made
What occurs during chemiosmosis in oxidative phosphorylation?
-A proton gradient is created & protons diffuse down the concentration gradient through ATP synthase
-As protons flow through ATP synthase, energy is released, which converts ADP + Pi to ATP
Why is oxygen called the final electron acceptor in oxidative phosphorylation?
After electrons reach end of ETC & protons have flowed through ATP synthase, they combine with/ O² to make water (H²O)
Where does ethanol fermentation take place?
Plants & yeast
What occurs during ethanol fermentation in anaerobic respiration?
-Pyruvate from glycolysis is converted to ethanal by enzyme Pyruvate decarboxylase.
-CO² is made as a by-product
-Ethanal is reduced to ethanol,catalysed by ethanol dehydrogenase
-NADH is oxidised by NAD
