5.2 - Factors Affecting Plasma Membranes

Question 1

How does temperature affect the permeability of a membrane

Answer 1

Permeability increases.
Temperature increases kinetic energy of phospholipids. As phospholipids move more, structure is lost. membrane becomes more fluid, increasing permeability.
Carrier and channel proteins become denatured, these support movement of substances. Permeability is affected.

Question 2

How does water affect the layout of plasma membranes

Answer 2

Tails of phospholipids are hydrophobic whilst phosphate grades are hydrophilic. Legs tuck themselves away from water whilst heads interact forming a hydrophobic core in a cell membrane.
Heads interacting with water keep bilayer intact.

Question 3

How do organic solvents affect cell membranes

Answer 3

As they are less or non polar, they dissolve the membrane.

Question 4

Why is alcohol used in antiseptics

Answer 4

Dissolved membrane of bacteria in a wound, killing them and reducing the risk of infection

Question 5

How do alcoholic drinks affect the body

Answer 5

The non polar parts of the alcohol will enter the membrane and disrupt the phospholipids. Membrane becomes more fluid and permeable.
Neuronal membranes need to be intact for their specific function. When disrupted, nerve impulses are no longer transmitted normally. Happens in the brain so persons behaviour changes.