Unit 1 - Cellular Respiration

Question 1

Where does Glycolysis Occur?

Answer 1

Cytoplasm

Question 2

Describe the process of Glycolysis

Answer 2

2 ATP are used but 4 ATP are generated​

Dehydrogenase enzymes remove hydrogen from intermediates​

Hydrogen is picked up by NAD to form NADH​

A series of intermediate molecules are formed

Question 3

Describe the process of the Citric Acid Cycle

Answer 3

The citric acid cycle is the second stage of respiration, after glycolysis​

It will only occur if oxygen is present, in the matrix of the mitochondria​

Pyruvate is broken down into an acetyl group, which binds with coenzyme A to form acetyl coenzyme A.​

CO₂ and hydrogen are released

Acetyl from Acetyl CoA combines with oxaloacetate to form citrate.​

In the citric acid cycle, Dehydrogenase enzymes remove hydrogen ions and electrons which are swept up by NAD to form NADH.​ NADH from glycolysis and the citric acid cycle pass hydrogen onto the ETC

One ATP is formed and CO₂ is released

Question 4

Describe the role of ATP in Glycolysis

Answer 4

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.

Question 5

What is the ETC

Answer 5

The electron transport chain is a chain of protein molecules attached to the inner membrane of the mitochondria

Question 6

Describe the ETC

Answer 6

Electrons are passed along the ETC and release energy​

The energy released is used to pump hydrogen ions across the mitochondrial membrane to the intermembrane space

The return flow of hydrogen back into the matrix through ATP synthase generates ATP from ADP + Pi.​

At the end of the chain, electrons and hydrogen combine with oxygen to form water​

Oxygen is the final hydrogen ion and electron acceptor.

Question 7

Explain the role of ATP in energy transfer

Answer 7

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

This includes; ​
* Protein synthesis ​
* Active transport​
* DNA replication ​
* Carbon fixation ​
* Contraction of muscles ​
* Transmission of nerve impulses

Question 8

Explain the role of ATP in Phosphorylation

Answer 8

Phosphorylation is an enzyme controlled process where a phosphate group is added to a molecule​

ADP + Pi -> ATP​

Phosphorylation also occurs when phosphate and energy are transferred from ATP to reactants in a metabolic pathway​

Glucose -> glucose-6-phosphate