Membrane Dynamics

Question 1

Functions of the plasma Membrane

Answer 1

1. Physical barrier- defines the boundary of the cell, structural support.
2. Controls the passage of materials from inside to outside and from outside to inside the cell.
3. Communication between the cell and its environment, governs interaction with other cells
4. Maintains the difference in chemical composition between the intercellular and extracellular fluid.

Question 2

Molecules that can pass through membrane

Answer 2

Oxygen, water, lipids, carbon dioxide

Question 3

Molecules that require a channel

Answer 3

Ions, water

Question 4

Molecules that require Carriers

Answer 4

Glucose, amino acids, ions

Question 5

Permeable

Answer 5

Allows substance to pass through

Question 6

Impermeable

Answer 6

Membrane does not allow it to pass

Question 7

Which bio-molecules are components of the Fluid Mosaic Model of the Plasma Membrane

Answer 7

Proteins, phospholipids, Cholesterol, Glycolipids/Glycoproteins

Question 8

Functions of the Membrane Proteins

Answer 8

1. Structural- maintains the shape of the cell
2. Enzymes- catalyze chemical reactions
3. Receptors for hormones and other signal molecules
4. Transporters of molecules across the cell membrane

Question 9

Carrier Proteins

Answer 9

1. Glucose and amino acids cross membrane only by carriers
2. Very Selective about what they transport
3. Slower transport than channel proteins
4. Carrier proteins are open to one side of the membrane or the other but NOT both.

Question 10

Intracellular Fluid

Answer 10

within the cells

Question 11

Extracellular fluid

Answer 11

outside the cells

Question 12

Extracellular fluid is further divided into:

Answer 12

plasma and interstitial fluid