Key area 7- Cellular Respiration

Question 1

What is cellular respiration?

Answer 1

.It is a series of metabolic pathways that releases energy from food and generates a high energy compound called adenosine triphosphate (ATP)

Question 2

What are the three stages involved in cellular respiration?

Answer 2

.Glycolysis, which occurs in the cytoplasm
.Citric acid cycle, which occurs in the central matrix of mitochondria
.Electron transport chain, which occurs in the inner membrane of mitochondria

Question 3

What are the two stages of Glycolysis?

Answer 3

.It is the breakdown of glucose to pyruvate, and occurs in the cytoplasm of the cell and doesn’t require oxygen
.The first stage is the energy investment phase, which requires ATP for the phosphorylation of glucose. During phosphorylation, which is an enzyme-controlled reaction, a phosphate group (Pi) is added to a molecule.
.The second stage is the energy pay off phase, which releases more energy and results in a net gain of 2ATP.
.Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme molecule NAD and dorms NADH. The hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane.
.If oxygen is present then pyruvate is broken down into carbon dioxide and an acetyl group that combines with coenzyme A forming acetyl coenzyme A

Question 4

What are the stages of the citric acid cycle?

Answer 4

.It occurs in the matrix of the mitochondria.
.The first stage is that the acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate
.It is enzyme-controlled and citrate is converted back into oxaloacetate which results in the generation of ATP and the release of carbon dioxide
.Dehydrogenase enzymes remove hydrogen ions and electrons and pass them to the coenzyme molecule NAD which forms NADH. The hydrogen ions and electrons from NADH are passed to the electron transport chain on the inner mitochondrial membrane

Question 5

What are the stages of the electron transport chain?

Answer 5

.It is a series of carrier proteins attached to the inner mitochondrial membrane
.The first stage is that the electrons are passed along the electron transport chain and releases energy. This energy allows H+ ions to be pumped across the inner mitochondrial membrane
.The return flow of H+ ions back through the membrane protein ATP synthase, and results in the production of ATP
.Finally, hydrogen ions and electrons combine with oxygen to form water

Question 6

What is ATP composed of?

Answer 6

.adenosine
.three inorganic phosphate (Pi) groups

Question 7

What cellular processes require the ATP to transfer them energy?

Answer 7

.Muscle contraction
.Active transport
.Synthesis, e.g. protein
.Transmission of nerve impulses