Higher Biology Unit 2.2

What is the word equation for respiration?

Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP)

Describe the two stages of glycolysis and describe the location

Glycolysis, the breakdown of glucose to pyruvate, occurs in the cytoplasm of the cell. ATP is required for the phosphorylation of glucose and intermediates during the energy investment phase of glycolysis. This leads to the generation of more ATP during the energy pay-off stage and results in a net gain of ATP.

Describe the electron transport chain. State the location

The electron transport chain is a series of carrier proteins attached to the inner mitochondrial membrane. Electrons are passed along the Electron Transport Chain releasing energy. This energy allows Hydrogen ions to be pumped across the inner mitochondrial membrane. The flow of these ions back through the membrane protein ATP Synthase, results in the production of ATP. Finally, hydrogen ions and electrons combine with oxygen to form water. Oxygen is required during the aerobic phase of respiration since it is the final hydrogen acceptor, combining with hydrogen ions & electrons to form water.

Describe the function of and draw a diagram of ATP and its formation

ATP is used to transfer energy to cellular processes which require energy. E.g the ATP released during aerobic respiration provides the energy required for Protein Synthesis.

Describe the role of NAD in cell respiration

Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the

Coenzyme NAD it’s role is to form NADH

Describe the role of dehydrogenase in cell respiration

Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the Coenzyme NAD

Describe the role hydrogen in cell respiration

The primary energy source

Describe the role of ATP synthase in cellular respiration

ATP is used to transfer energy to cellular processes which require energy

Describe the role of oxygen in cellular respiration

Oxygen is required during the aerobic phase of respiration since it is the final hydrogen acceptor, combining with hydrogen ions & electrons to form water.

Describe the citric acid cycle. Include: oxaloacetate, citrate and CoA. State the location

The Aerobic phase of respiration takes place in the Matrix of Mitochondria. In the presence of oxygen, Pyruvate is then broken down to an Acetyl Group that combines with Coenzyme A forming Acetyl Coenzyme A. In the Citric Acid Cycle, the Acetyl group from Acetyl Coenzyme A combines with Oxaloacetate to form Citrate. During a series of enzyme controlled steps, Citrate is gradually converted back into Oxaloacetate which results in the generation of ATP and release of Carbon Dioxide. Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the Coenzyme NAD, forming NADH. This occurs in both Glycolysis and the Citric Acid Cycle. The hydrogen ions and electrons from NADH are passed to the Electron Transport Chain on the inner mitochondrial membrane.

Describe fermentation in plant/yeast

In the absence of oxygen, fermentation takes place in the cytoplasm. In plant & yeast cells, the Pyruvate is converted to Ethanol and CO2 in a reversible reaction. Fermentation results in much less ATP being produced than in aerobic respiration.

Describe fermentation in animal cells

In animal cells, the Pyruvate is converted to Lactate in a reversible reaction.