Lecture 7 - Composition & Function of The Plasma Membrane

Question 1

What type of cells has a plasma membrane?

Answer 1

Eukaryotic Cells

Question 2

What is the plasma membrane?

Answer 2

the boundary that separates the living cell from its surroundings. Essential for all cells

Question 3

What is the role of the plasma Membrane?

Answer 3

it acts as a barrier to prevent the contents of the cell from escaping and mixing with molecules in the environment

Question 4

What type of permeability does the plasma membrane have?

Answer 4

Selective permeability allowing some substances to cross it more easily than others

Question 5

What are lipid bilayers?

Answer 5

when lipids are arranged in two closely apposed sheets in which proteins are embedded and some carbohydrates

Question 6

What are the most abundant lipids in the plasma membrane?

Answer 6

Phospholipids

Question 7

What are Glycolipids?

Answer 7

lipids containing sugars representing their hydrophilic head

Question 8

What are the 4 major functions of membrane proteins?

Answer 8

• Transport of Molecules
• Enzymatic Activity
• Signal Transduction/cell communication
• Structural Support - attaches to the extracellular matrix

Question 9

What are the 2 types of transport?

Answer 9

• Passive Transport
• Active Transport

Question 10

What is passive transport?

Answer 10

When molecules move across the membrane without wasting energy from areas with high concentrations to a low concentration

Question 11

What are the 3 types of Passive Transport?

Answer 11

• Diffusion
• Osmosis
• Facilitated Diffusion

Question 12

What is Diffusion

Answer 12

free movement of molecules across the lipid bilayer from high to low concentration areas until equilibrium is reached

Question 13

What is Osmosis

Answer 13

spontaneous movement of water across a semipermeable membrane from high water potential to a solution with low water potential

Question 14

What is High water potential?

Answer 14

Low solute (water) concentration

Question 15

What is low Water potential?

Answer 15

High solute (water) concentration

Question 16

What is Osmotic pressure?

Answer 16

hydrostatic pressure is required to stop the net flow of water across a membrane - done by separating water potentials

Question 17

What is Tonicity

Answer 17

the ability of a surrounding solution to cause a cell to gain or lose water

Question 18

What is an isotonic solution?

Answer 18

solution with the same water concentration inside and outside the cell

Question 19

What is a hypertonic solution?

Answer 19

solution with higher water concentration outside the cell than inside

Question 20

How can osmosis pressure impact blood cells in hypertonic solutions?

Answer 20

change in osmotic pressure can cause cells to swell or shrink rapidly

Question 21

What is Facilitated diffusion?

Answer 21

passive movement of molecules down a concentration gradient via transport proteins

Question 22

What are the 3 transporter types for passive transport?

Answer 22

• Uniporters
• Symporters
• Antiporters

Question 23

What is Endocytosis

Answer 23

Uptake (from outside to inside) of macromolecules and large proteins

Question 24

What are the 3 types of Endocytosis?

Answer 24

• Phagocytosis
• Pinocytosis
• Receptor - mediated Endocytosis

Question 25

What are the 3 types of Endocytosis?

Answer 25

• Phagocytosis
• Pinocytosis
• Receptor-mediated Endocytosis

Question 26

What is Exocytosis

Answer 26

secretion / excretion (from inside to outside)