Chapter 7

Question 1

Define cellular respiration

Answer 1

Cellular respiration is a series of chemical reactions in which glucose is broken down to release its stored energy. In this process, the energy released from glucose is used to make ATP (adenosine triphosphate).

Question 2

What is the cellular respiration equation?

Answer 2

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 3

Where does Cellular respiration occur?

Answer 3

Cellular respiration takes place in the mitochondria of cells (although it starts off in the cytosol).
Mitochondria are found in almost all eukaryotic cells.
A mitochondrion’s structure is key to its role in cellular respiration.

Question 4

What is the structure of the mitochondria?

Answer 4

Outer and inner membrane
Intermembrane space – the space between the inner and outer membrane.
Matrix – the thick fluid enclosed by the inner membrane.
Cristae – the infoldings of the inner membrane that project into the matrix.

Question 5

Define glycolysis

Answer 5

Occurs in the cytosol of the cell.
Glucose is broken down into 2 pyruvate molecules.
2 ATP produced

NO OXYGEN IS REQUIRED

The ATP can be used immediately for some organisms- however this isn’t sufficient to sustain multicellular organisms long term - further processing of pyruvate extracts more energy.

Question 6

Define the link reaction

Answer 6

The 2 (3 carbon) pyruvate molecules formed in glycolysis enter into the matrix of the mitochondrion
Acetyl CoA (2 carbon) enters the Krebs cycle
It also releases carbon dioxide, a waste product that is exhaled and makes NADH for the third stage of aerobic respiration

Question 7

Define the kreb cycle

Answer 7

By breaking down acetyl CoA, protons, and high energy electrons are released. These protons and electrons are loaded onto NAD+ and FAD to generate high energy NADH and FADH2.

The krebs cycle produces 2 ATP

The kreb cycle produces 2 CO2 molecules for every one acetyl CoA molecule, plus the one C02 molecule from the link reaction. This means that a total of six CO2 molecules are produced for every glucose molecule

Question 8

Define the electron transport chain

Answer 8

This is where most of the ATP is produced.
Hydrogen from NADH and FADH2 splits into H+ and e-
The electrons are passed between enzymes called cytochromes, losing a bit of energy each time.
This energy is used to pump the hydrogen ions into the intermembrane space (by active transport).
Occurs on the folds of the inner mitochondrial membrane (cristae).