Respiration 1

Question 1

Overview of mitochondria

Answer 1

Mitochondria are rod-shaped organelles 0.5 - 1.0 µm in diameter
They are the site of aerobic respiration in eukaryotic cells
The function of mitochondria is to synthesize ATP
Synthesis of ATP in the mitochondria occurs during the last stage of respiration called oxidative phosphorylation
This relies on membrane proteins that make up the ‘electron transport chain’ and the ATP synthase enzyme – the details of this are covered later in the notes

Question 2

Structures of the two membranes of mitochondria

Answer 2

The outer membrane is:
Smooth
Permeable to several small molecules

The inner membrane is:
Folded (cristae)
Less permeable
The site of the electron transport chain (used in oxidative phosphorylation)
Location of ATP synthase (used in oxidative phosphorylation)

Question 3

what is the intermembrane space

Answer 3

The intermembrane space:
Has a low pH due to the high concentration of protons
The concentration gradient across the inner membrane is formed during oxidative phosphorylation and is essential for ATP synthesis

Question 4

What is the matrix

Answer 4

The matrix:
Is an aqueous solution within the inner membranes of the mitochondrion
Contains ribosomes, enzymes and circular mitochondrial DNA necessary for mitochondria to function

Question 5

Relationship between structure & function

Answer 5

The structure of mitochondria makes them well adapted to their function
They have a large surface area due to the presence of cristae (inner folds) which enables the membrane to hold many electron transport chain proteins and ATP synthase enzymes
More active cell types can have larger mitochondria with longer and more tightly packed cristae to enable the synthesis of more ATP because they have a larger surface area
The number of mitochondria in each cell can vary depending on cell activity
Muscle cells are more active and have more mitochondria per cell than fat cells

Question 6

Type of stuff respiration is used for.

Answer 6

Transporting substances across the membrane.

Anabolic reactions.

movement.

maintaining body temperature.

Question 7

What are the four stages of photosynthesis

Answer 7

Glycolysis takes place in the cell cytoplasm
The Link reaction takes place in the matrix of the mitochondria
The Krebs cycle takes place in the matrix of the mitochondria
Oxidative phosphorylation occurs at the inner membrane of the mitochondria