Respiration Flashcards
Why do organisms need to respire?
To provide ATP for:
Active transport against conc gradients
Metabolic reactions
Muscle contraction
Releases heat for thermoregulation
What are the 4 main stages of aerobic respiration and where do they occur?
- Glycolysis (cyctoplasm)
- Link reaction (matrix)
- Krebs cycle (matrix)
- Oxidative phosphorylation (cristae)
Outline the stages of glycolysis
Glucose phosphorylated into hexose bisphosphate by 2 ATP
Hexose bisphosphate broken down into 2 triose phosphate (TP)
TP oxidised to form 2 pyruvate
Net gain of reduced NAD and 2 ATP per glucose
How does pyruvate from glycolysis enter the mitochondria?
Active transport
What happens during the link reaction and what are the products formed
Oxidation of pyruvate to acetate
Acetate combines with coenzyme A to form acetylcoenzyme A
(Products formed = CO2, reduced NAD & Acetyl coA)
State the equation for the link reaction
Pyruvate + NAD + CoA
Acetyl CoA + reduced NAD + Co2
What happens in the Krebs cycle?
2C Acetyl CoA enters the cycle
Accepted by 4C oxeoacetate
Forming 6C citrate
Which loses CO2 and a hydrogen atom to produce one ATP
reduced FADH2 & NAD also produced
What happens in the ETC?
Electrons released from reduced NAD and FAD
undergo successive redox reactions
Energy releases heat and maintains proton gradient
O2 is the final electron acceptor
How does chemiosmosis produce ATP during aerobic respiration?
Hydrogen ions move down a concentration gradient via the channel protein ATP synthase.
ATP synthase catalyses ADP +pi makes ATP
What happens in aerobic respiration in some yeast and plant cells?
Much less ATP produced as only glycolysis continues
Pyruvate is decarboxylated to form ethanal
Ethanal is reduced to ethanol
Describe the structure of the mitochiondrion
Surrounded by a double membrane
Folded inner membrane forms cristae which is the site of the ETC
Fluid matrix contains DNA, enzymes, lipids and proteins
