Cell Membrane and Passive Transport

The cell membrane is semi or selectively permeable. This means that

• all types of molecules may pass through it easily
• only certain molecules may pass through
• molecules cannot cross the membrane

Which number is pointing to the hydrophobic part of the phospholipid?

• 1
• 2
• 3
• 4

Can the water in the picture cross easily through the membrane?

• Yes
• No

In the process of diffusion molecules move from _________________ through the membrane.

• Low concentration to High concentration
• High concentration to Low concentration

What are the yellow molecules that are embedded in the membrane? (They help stabilize the membrane)

• phospholipids
• proteins
• cholesterol
• sugar

What are the purple molecules embedded in the membrane in the picture?

• Phospholipids
• Cholesterol
• Proteins

What do the purple molecules do in the picture?

• Stabilize the membrane
• Keep molecules, such as sugar and water from passing through
• Act as a doorway to allow molecules like water and sugars to pass through

Which process requires NO ENERGY, but requires a protein to help molecules move from HIGH to LOW through the membrane?

• simple diffusion
• facilitated diffusion
• active transport