2.6 Membrane Transport

• What does membrane transport refer to?

  Substance movement across the cell membrane
• Passive transport moves substances down a concentration gradient without cellular energy.
• Passive transport moves substances against the concentration gradient.

  False
• What is the source of energy for active transport?

  ATP
• Passive transport moves substances down the concentration gradient, while active transport moves substances against the concentration gradient.
• Passive transport moves substances across the cell membrane without using cellular energy.
• Which type of passive transport requires no membrane proteins?

  Simple diffusion
• Simple diffusion moves substances down their concentration gradient without any membrane proteins.
• Facilitated diffusion uses membrane proteins to help large or polar molecules cross the cell membrane.
• What type of transport is simple diffusion?

  Passive
• Facilitated diffusion requires membrane proteins to assist the movement of large or polar molecules.


  True
• How do carrier proteins move molecules across the membrane?

  Conformational change
• Match the protein type with its mechanism:

  Carrier proteins ↔️ Bind and change shape

  Channel proteins ↔️ Form pores
• What is the primary role of membrane transport?

  Maintain cell homeostasis
• Active transport requires cellular energy to move substances against their concentration gradient.


  True
• An example of active transport is the sodium-potassium pump
• What are two examples of passive transport?

  Diffusion and osmosis
• Osmosis is the movement of water across a semi-permeable membrane
• Which type of passive transport requires membrane proteins to assist larger or polar molecules?

  Facilitated diffusion
• Carrier proteins undergo a conformational change to move molecules across the membrane.


  True
• Facilitated diffusion helps large or polar molecules cross the cell membrane down their concentration gradient
• What determines the direction of water flow in osmosis?

  Tonicity
• Glucose transporters are highly specific
• What is the role of membrane proteins in facilitated diffusion?

  Help molecules cross
• Match the type of tonicity with the direction of water flow:

  Hypotonic ↔️ Water flows into the cell

  Isotonic ↔️ No net water flow

  Hypertonic ↔️ Water flows out of the cell
• What happens to a red blood cell in a hypotonic solution?

  Swells and bursts
• Primary active transport uses electrochemical gradients as its energy source.

  False
• ATP-powered pumps move substances against their gradient
• Why is membrane transport essential for cell homeostasis?

  Regulates entry and exit
• Active transport requires ATP to move substances against their concentration gradient.

  True
• What type of molecules are transported in simple diffusion?

  Small, nonpolar molecules
• Osmosis requires membrane proteins for water movement.

  False
• What type of molecules can pass through the cell membrane via simple diffusion?

  Small, nonpolar molecules
• Osmosis involves the movement of water across a semi-permeable membrane without any protein assistance.


  True
• Match the type of passive transport with its description:

  Simple diffusion ↔️ Direct passage through the membrane

  Facilitated diffusion ↔️ Passage assisted by membrane proteins

  Osmosis ↔️ Movement of water through a semi-permeable membrane
• Which type of molecule is transported by simple diffusion?

  Small, nonpolar
• Facilitated diffusion requires the use of membrane proteins to transport molecules across the cell membrane.


  True
• Arrange the following types of passive transport by the type of molecule they transport:

  1️⃣ Water

  2️⃣ Small, nonpolar

  3️⃣ Large, polar
• Carrier proteins in facilitated diffusion undergo a conformational change
• Which type of protein in facilitated diffusion is highly specific?

  Carrier proteins