Cell Membrane Transport Mechanisms

The video tutorial covers membrane transport, focusing on simple and facilitated diffusion. Simple diffusion involves the movement of small, hydrophobic molecules down a concentration gradient without energy or proteins. Facilitated diffusion, however, requires proteins to transport larger, hydrophilic molecules. Carrier proteins are specific to certain molecules like glucose and amino acids, while channel proteins allow ions to pass through. The video emphasizes the differences between these diffusion types and the role of proteins in facilitating the transport of specific molecules.

What is the primary function of the cell membrane?

• To provide energy to the cell

• To control what enters and exits the cell

• To store genetic information

• To produce proteins

Which of the following is NOT a type of membrane transport?

• Simple diffusion

• Facilitated diffusion

• Photosynthesis

• Osmosis

Simple diffusion involves the movement of molecules from an area of _____ concentration to an area of _____ concentration.

• low; high

• high; low

• equal; equal

• none; some

Which type of molecules typically move through the membrane via simple diffusion?

• Proteins

• Small and hydrophobic

• Ions

• Large and hydrophilic

Facilitated diffusion is necessary for which type of molecules?

• Gaseous molecules

• Lipids

• Large and hydrophilic

• Small and hydrophobic

What role do proteins play in facilitated diffusion?

• They provide energy for transport

• They store molecules

• They act as channels or carriers for molecules

• They break down molecules

Which of the following is a characteristic of channel proteins?

• They form a continuous passageway

• They transport molecules one at a time

• They require ATP to function

• They are specific to a single type of molecule

Carrier proteins are specific to:

• Any molecule

• All hydrophobic molecules

• Only ions

• A particular molecule

Why can't ions pass through the membrane via simple diffusion?

• They require ATP

• They are hydrophilic and charged

• They are not present in cells

• They are too large

What is a key difference between channel and carrier proteins?

• Channel proteins are slower

• Carrier proteins can transport multiple molecules simultaneously

• Carrier proteins require ATP

• Channel proteins can transport many molecules at once