Respiration Flashcards
Describe the structure of adenosine triphosphate (ATP)
ATP consists of the base adenine, the pentose sugar ribose and 3 phosphate groups
What is ATP’s role in our cells?
It is an immediate source of energy
How is energy released from ATP?
ATP is hydrolysed to ADP + Pi using the enzyme ATPase
How is ATP synthesised?
It is synthesised from ADP + Pi (phosphorylation) in a condensation reaction, using the enzyme ATP synthase. This requires energy
Why is ATP the universal molecule of energy in living things?
-it releases small amounts of energy
-energy is released in small manageable steps
-hydrolysis of ATP is a single reaction (breaking of one phosphate bond)
-it is small and soluble so can be transported around a cell
List the main 4 stages of respiration and where they occur
-Glycolysis-> cytoplasm/cytosol
-Link reaction/ pyruvate oxidation-> matrix of mitochondria
-Krebs Cycle-> matrix of mitochondria
-Electron Transport Chain-> inner mitochondrial membranes of cristae
Name the only stage in respiration that can occur in both aerobic and anaerobic conditions
Glycolysis
What end product is each molecule of glucose converted to during glycolysis?
2 molecules of pyruvate
Glucose is initially phosphorylated in glycosides to activate it. Where does the phosphate come from?
The hydrolysis of 2 ATP molecules
What is the name of the intermediate that glucose is converted to when it is initially phosphorylated
Fructose bisphosphate
What is each fructose bisphosphate split into
2 molecules of triose phosphate
In the oxidation of the 2 molecules of triose phosphate into 2 molecules of pyruvate, how many ATPs are produced
4 ATP in total
In the oxidation of the 2 molecules of triose phosphate into 2 molecules of pyruvate, what happens to the hydrogen removed from them?
It is used to reduce 2 molecules of the coenzyme NAD to NADH (result is 2 NADHs)
What is the overall net production of ATP from glycolysis?
2 ATP
In the link reaction, what are the two pyruvate molecules converted to?
2 acetyl coenzyme A molecules
What 2 processes does pyruvate undergo in the link reaction?
- Decarboxylation (when CO2 is removed)
- Dehydrogenation (when hydrogen is removed)
In the link reaction, what happens to the hydrogen removed from the 2 pyruvate molecules?
It is used to reduce 2 molecules of NAD to NADH
Overall in the link reaction, what happens?
2 molecules of pyruvate are converted to 2 molecules of acetyl CoA, with the release of 2 molecules of CO2 and 2 molecules of NADH
To keep the link reaction going, what must always be available for feeding back into it?
-NAD
-coenzyme A
What does acetyl CoA combine with when it enters Krebs Cycle?
Acetyl CoA (2C) combines with oxaloacetate (4C) to from citrate (6C)
