12 - Respiration Flashcards
What are the four stages of aerobic respiration?
Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation
Where does glycolysis take place?
Cytoplasm
What are the four stages of glycolysis?
Phosphorylation of glucose to phosphorylated glucose
Lysis of phosphorylated glucose to triose phosphate
Oxidation of triose phosphate
Production of ATP
What are the end products of glycolysis?
2 pyruvate molecules
4 ATP molecules
Reduced NAD
How and why is glucose phosphorylated in glycolysis?
Two ATP molecules each lose an inorganic phosphate to the glucose, leading to two ADP molecules. The glucose activation energy is decreased.
How many hydrogen molecules are removed in the oxidation of triose phosphate?
Each triose phosphate loses 2 hydrogen molecules to NAD.
Where does the link reaction take place?
Matrix of the mitochondria
Describe the link reaction process.
Pyruvate is oxidised to acetate, losing CO2 and reducing NAD by losing 2H in the process. Acetate combines with coenzyme A to produce acetylcoenzyme A.
How many carbons does acetate have?
2
Where does the Krebs cycle occur?
Matrix of mitochondria
Describe the stages of the Krebs cycle.
AcetylCoA + C4 molecule goes to C6 molecule
2CO2 is formed and reduced NAD and reduced FAD and 1ATP
Forms the C4 molecule again
What are the products of Krebs cycle for one molecule of pyruvate?
Reduced FAD, reduced NAD
1ATP
2CO2
Where does oxidative phosphorylation occur?
Cristae of mitochondria
How are more metabolically active cells adapted?
More mitochondria
More densely folded cristae
Where do electrons entering the Electron Transfer Chain come from? (Respiration)
From reduced NAD and reduced FAD, forming NAD and FAD
How do protons move from the matrix into the inter-membrane space?
Active transport, using the energy released from the movement of electrons down the ETC.
How do protons move from the inter-membrane space into the matrix?
Facilitated diffusion through ATP synthase channels
What is the terminal acceptor of electrons in the respiration ETC? What does it it join with and what does this prevent?
Oxygen, to form water when combined with the electrons and protons. This stops ‘electron/proton backup’
Why do electrons move down the ETC rather than releasing all energy at once?
The more released in one go, the more is lost as heat.
How much energy can lipids release?
More than twice that of the same mass of carbohydrate
What are the products of anaerobic respiration in plants?
Ethanol, CO2, NAD
What are the products of anaerobic respiration in animals?
Lactate, NAD
What is the only stage of respiration that can occur when anaerobic?
Glycolysis
What is lactate formed from?
The reduction of pyruvate to regenerate NAD.
Mitochondria in muscle cells have more cristae than mitochondria in skin cells. Explain the advantage of mitochondria in muscle cells having more cristae. (2)
More oxidative phosphorylation
Muscle cells use more ATP
