Unit 9: Cell membranes functions and structure

Question 1

What is the cell membrane?

Answer 1

boundary between inside the cell

Question 2

What does selectively permeable mean?

Answer 2

• Only lets certain things in and out
• maintains homeostasis
• identifies and communicates with certain cells
• used to recognize and attack foreign cells

Question 3

Why is the cell membrane called the Fluid Mosaic Model

Answer 3

• Fluid - always moving; not rigid
• Mosaic - different organic molecules

Question 4

What is a phospholipid bilayer?

Answer 4

• two layers of phospholipids

Question 5

Is the phosphate group Polar or nonpolar, and hydrophilic or hydrophobic?

Answer 5

• head of phospholipid
• polar
• hydrophilic

Question 6

What is the difference between Hydrophilic and hydrophobic?

Answer 6

• hydrophobic - repels water
• hydrophilic - attracted to water

Question 7

Are fatty acids polar or nonpolar and what does it do to ions and polar molecules?

Answer 7

• Fatty acids repel polar molecules and ions

Question 8

What is glycerol?

Answer 8

• Connect head and tail to make a phospholipid

Question 9

What are the five types of proteins?

Answer 9

• cholesterol
• Marker proteins/glycoproteins
• Receptor proteins
• Transport/channel proteins
• enzymes

Question 10

What is the structure and function of cholesterol?

Answer 10

• stabilizes phospholipid tails in hot and cold environments
• keeps phospholipids from becoming too soft or hard
• important for homeostasis

Question 11

What is the structure and function of a marker protein/glycoprotein

Answer 11

• Protein with carbohydrates attached on cell exterior
• unique to each cell
• help in cell recognition
• helps immune system for organ transplants

Question 12

what is the structure and function of a receptor protein?

Answer 12

• recognizes and binds substances on the extracellular side
• Can change shape
• knows what the cell needs and gets it

Question 13

What is the structure and function of Transport/channel proteins?

Answer 13

• helps substances move in and out of cell
• has an opening all the way through the protein

Question 14

What is the structure and function of an enzyme?

Answer 14

• used in chemical reactions
• can be on either extracellular or intracellular side
• has binding site where it hold onto molecules used in chemical reaction- active site

Question 15

What are the two ways proteins can be described?

Answer 15

• Integral - go all the way through the membrane
• Peripheral - sit on the inside or outside of the membrane