1G Cellular Respiration Flashcards
What is respiration?
Glucose is broken down (hydrogen ions being removed and the transfer of electrons by dehydrogenase enzymes) to release ATP.
What is the role of ATP?
Transfer of energy (energy source) and providing phosphate for the phosphorylation of molecules.
What is the role of dehydrogenase enzymes?
To remove H ions from respiratory substrates.
What are NAD and FAD?
Co-enzymes which accept H ions.
NAD and FAD become NADH and FADH2 respectively. They are said to have become what?
Reduced.
Describe Glycolysis.
- Glucose (6C) is phosphorylase into an intermediate 1. The phosphate is provided by ATP forming ADP.
- The enzyme Phosphofruktokinase phosphorylates the 2nd intermediate to become another intermediate molecule 3. The phosphate is provided by ATP forming ADP.
- Further chemical reactions take place to convert the intermediate 3 into 2 molecules of pyruvate (3C), generating 4ATP. Net gain of 2 ATP.
Where does glycolysis take place?
The cytoplasm.
Does glycolysis require oxygen to take place?
No.
Why is it called the energy investment stage?
2ATP are required to start the process of glycolysis.
Why is it called the energy payoff stage?
4ATP are produced giving a net gain of 2ATP.
What is the function nod phosphofruktokinase?
To phosphorylase fructose 1-6 phosphate into fructose 1-6 Bi-Phosphate.
What molecule donated its phosphate so that phosphorylation can take place?
ATP
Describe the stages of the link stage and Citric Acid Cycle.
- Pyruvate (3C) is converted into an Acetyl Group (2C). CO2 is released.
- Each Acetyl Group combines with coenzyme A to form Acetyl coenzyme A. During the process, further H+ are removed from and join to NAD (becoming NADH2).
- The acetyl group (2C) of the Acetyl coenzyme A joins with a molecule of oxaloacetate (4C) to form citrate (6C).
- Further enzyme controlled steps take place, releasing CO2,H+. H+ becomes bound to NAD and FAD.
- ATP is generated and oxaloacetate is regenerated to continue the cycle.
What gas is produced when 3 carbon pyruvate is converted into 2 carbon Acetyl Coenzyme A?
CO2.
How is citrate formed?
4 carbon Acetyl group combines with carbon oxaloacetate to form 6 carbon citrate.
Is ATP generated during the Citric Acid Cycle?
Yes. 1 ATP molecule per cycle.
Is CO2 released during the Citric Acid Cycle?
Yes. When citrate is broken down into the first two intermediates.
Is oxaloacetate regenerated during the cycle?
Yes.
What is the electron transport chain?
Consists of a group of protein molecules.
Where are these found?
Attached to the inner membrane of the mitochondria.
What are Cristae?
Christae are folds of inner mitochondrial membrane which increase the surface area for ATP production.
What is the purpose of the cristae having more folds?
More folds, more ATP produced.
What type of cells contain more cristae and more with increased number of folds?
Active cells such as muscle and speed cells have increased number of folds in their mitochondria.
Do NADH and FADH release high-energy electrons to the electron transport chain on the mitochondrial membrane which results in the bulk of ATP?
Yes.
Describe what happens during ATP synthesis?
High energy electrons are used to pump hydrogen ions across the membranes and the flow of these back through the membrane synthesises ATP using the membrane protein ATP synthase.
Name the final oxygen and electron acceptor?
Oxygen.
Name alternative respiratory substrates.
Fats, proteins, fatty acids, glycerol, Amin acids.
Is cellular respiration regulated by feedback inhibition?
Yes.
Which two substances inhibit the action of phosphofruktokinase?
ATP and Citrate.
Why does these substances inhibit phosphofruktokinase?
To synchronise the rates of glycolysis and the Citric Acid cycle.
