Membranes worksheet

Question 1

Describe selective permeability

Answer 1

how cells maintain homeostasis by choosing what passes through the membrane and what doesn’t

Question 2

Describe how the cell membrane achieves selective permeability

Answer 2

phospholipid bilayer with embedded proteins that allow certain molecules to pass through the membrane based on size, polarity, and charge

Question 3

How does the amphipathic nature of membranes affect transport across the membrane?

Answer 3

by creating a selective barrier that allows certain molecules to readily pass through while hindering others

Question 4

What role do proteins play in transport across membranes?

Answer 4

by acting as specialized channels that allow specific molecules to pass through the membrane that would otherwise not be able to due to the hydrophobic interior of the phospholipid bilayer

Question 5

How is the cell membrane different from the cell wall?

Answer 5

cell walls are rigid, while the cell membrane is fluid and changes shape and changes size

Question 6

What are roles of cholesterol in the membrane?

Answer 6

helps keep saturated fatty acid chains separated, creates space in the membrane, is important for membrane fluidity and permeability, helps prevent membranes from freezing at cold temperatures, helps keep unsaturated fatty acid phospholipid molecules stuck together

Question 7

What are glycoproteins made of?

Answer 7

carbohydrates attached to proteins

Question 8

What is the function of glycoproteins in cell membranes?

Answer 8

identifies different types of cells, receptors on the cell surface, cell-to-cell signaling, viruses use glycoproteins to get into the cell

Question 9

What are glycolipids made of?

Answer 9

carbohydrates attached to lipids

Question 10

What is the function of glycolipids in cell membranes?

Answer 10

identifies different cell types

Question 11

Water can pass through cell membranes only at a very minimal rate, explain why water doesn’t just flow through the cell membrane

Answer 11

the interior of the phospholipid bilayer is hydrophobic and doesn’t allow polar molecules to easily pass through

Question 12

What are the characteristics of substances that can easily move across a cell membrane?

Answer 12

Oxygen gas, carbon dioxide, nitrogen gas
small, nonpolar molecules