CA #1 (Bio 2)

1. Which component of this membrane contains a hydrophobic region and acts as the primary barrier to most foreign substances?

• protein
• cholesterol
• carbohydrate chain
• phospholipid bilayer

2. Which component of this membrane is responsible for maintaining flexibility and fluidity, so that our membranes don't freeze?

• phopholipid bilayer
• cholesterol
• protein
• carbohydrate chain

3. Which component of this membrane is responsible for identifying materials outside of the cell?

• phopholipid bilayer
• cholesterol
• protein
• carbohydrate chain

4. Which statement BEST describes how channel and carrier proteins in the plasma membrane are similar?

• A. Both allow for the flow of molecules into and out of a cell.
• B. Both directly connect the membrane to the nucleus of a cell.
• C. Both use energy to continuously move water molecules out of a cell.
• D. Both cause the phospholipid bilayer to form a rigid membrane for a cell.

5. Which of the following is MOST involved in providing structure for a plasma membrane?

• A. the number of protein channels embedded in the membrane
• B. the types of carbohydrates attached to proteins on the surface
• C. the types of proteins that are attached to the surface of the membrane
• D. the arrangement of the hydrophobic and hydrophilic ends of the phospholipids

6. Which of the following is a protein responsible for communication?

• A
• B
• C
• D

7. Which of the following is responsible for allowing small, nonpolar molecules to enter/leave the cell?

• D
• E
• F
• G

8. What determines the direction that molecules move across a membrane?

• A. orientation of cholesterol in the plasma membrane
• B. concentration gradient across the plasma membrane
• C. configuration of phospholipids in the plasma membrane
• D. location of receptors on the surface of the plasma membrane

9. The relatively constant internal physical and chemical conditions that all organisms must maintain to survive is known as...

• Osmosis
• Endocytosis
• Homeostasis
• Exocytosis

10. Solute particles move from an area of higher concentration to an area of lower concentration in a process called...

• Osmosis
• Active transport
• Diffusion
• Equilibrium