Active and Passive Transport Review

Passive Transport Review

Diffusion is a naturally occurring process, where molecules flow with the natural concentration gradient(High to Low)

The goal of diffusion is for a system to be in a state of equilibrium - such that the concentration is balanced everywhere

“Passive” means without effort or

with no energy

“Transport” refers to molecules being

moved across a cell membrane

“Passive Transport” - moving molecules
across a cell membrane with no energy

required from the cell

Why does Passive Transport require
no energy from cells?

The natural flow of molecules is from a high area of concentration to low concentration - this happens on its own

The molecules do all the moving -
the cell does nothing to move them (NO ENERGY FROM THE CELL)

Multiple Choice

During Passive Transport, molecules move in a specific way across a Cell membrane so that they flow without requiring the cell to use any energy. How does the concentration gradient factor in the movement?

• Flow is High Concentration into Low Concentration

• Flow is Low Concentration into High Concentration

• Flow is Positive Concentration into Negative Concentration

• Flow is Negative Concentration into Positive Concentration

Multiple Choice

Passive Transport

• Does require cell energy

• Does NOT require cell energy

The 3 types of passive transport:

1. Simple Diffusion (small molec)

2. Osmosis (Water molec)

3. Facilitated Diffusion (Large Molec)

Simple Diffusion

Small molecules naturally flow with the concentration (high to low) gradient through the gaps in the
semi-permeable cell membrane
until equilibrium is achieved

The molecules do all the work of moving, and the membrane is passive in this process.

Equilibrium - when the concentration is the same throughout the entire solution, thus homeostasis has been maintained

Multiple Choice

_____________ allows some things to enter and leave cells, while keeping other things out of the cell.

• An impermeable membrane

• A semi-permeable membrane

• A permeable membrane

Multiple Choice

The process by which living things try to keep their internal conditions relatively stable (or balanced) is called - 

• homeostasis.

• cellular respiration.

• osmosis.

• diffusion.

Multiple Choice

Based on the direction that the molecules are traveling - does this diagram show molecules going with or against the flow of the concentration gradient?

• With the Flow

• Against the Flow

Multiple Choice

When both inside and outside of a cell have the same amount of water it is said that the cell has reached a state of

• Osmosis
• Diffusion
• Equilibrium

Facilitated Diffusion

The movement of Large or Charged molecules through the Protein Channels of a semi-permeable membrane from high to low concentration to achieve equilibrium

The proteins in the cell membrane does not use any energy for this to
occur - The molecules just move
through the proteins on their own.

​The ONLY difference between Facilitated and Simple is that PROTEINS FACILITATE A PATH FOR LARGE PROTEINS TO FLOW THROUGH SINCE THEY ARE TOO BIG TO FIT THROUGH THE GAPS IN THE LIPID BILAYER

Multiple Choice

What biomolecule is number one pointing to?

• Lipid

• Protein

• Nucleic Acid

• Carbohydrate

Multiple Choice

What is simple diffusion?

• when small molecules move move across a membrane from a low concentration to a high concentration 

• when large molecules move from a high concentration to a low concentration through a protein.

• when small molecules move move across a membrane from a high concentration to a low concentration 

• when large molecules move from a low concentration to a high concentration through a protein.

Multiple Choice

What is facilitated diffusion?

• when small molecules move move across a membrane from a low concentration to a high concentration 

• when large molecules move from a high concentration to a low concentration through a protein.

• when small molecules move move across a membrane from a high concentration to a low concentration 

• when large molecules move from a low concentration to a high concentration through a protein.

Multiple Choice

Does the protein use energy during facilitated diffusion to transport the molecules into the cell?

• NO

• YES

Osmosis

The movement of only water molecules through a semi-permeable membrane from high to low concentration to achieve equilibrium

(The cell membrane does not use any energy for this to occur -the water shifts on its own because of concentration
differences )

​3 types of tonicity
ISOTONIC
HYPERTONIC
HYPOTONIC

Multiple Choice

During osmosis

• water moves from high to low concentration
• large or oddly shaped molecules move across a cell membrane
• water moves when energy is used
• small molecules

Match

Match the following types of passive transport with the correct diagram.

Simple diffusion

Facilitated Diffusion (Protein Channel)

Osmosis (Water)

• Simple diffusion

• Facilitated Diffusion (Protein Channel)

• Osmosis (Water)

OSMOSIS 1: ISOTONIC solutions contain the same concentration of solutes in the cell and solution
- they are essentially at homeostasis

Water will cycle in and out of the cell since the environment inside the cell and outside the cell have
the same concentration.

OSMOSIS 2: HYPERTONIC If the cell has a high concentration of water inside then the water will flow out of the cell and Shrink

Water will flow out of the cell and into the surrounding environment in an attempt to bring them both to equilibrium so that their concentrations match.

OSMOSIS 3: HYPOTONIC If a solution has more water outside than the cell has inside then it is said to be HYPOTONIC because water will flow in to bring it to equilibrium

Water will flow into the cell from the surrounding environment in an attempt to bring them both to equilibrium so that their concentrations match.

Multiple Choice

What type of solution allows water to enter the plant cell?

• hypotonic solution
• hypertonic solution
• isotonic solution
• active transport

Multiple Choice

What type of solution is this cell in?

• Isotonic
• Hypertonic
• Hypotonic
• diffused

Multiple Choice

What type of solution is shown in the picture?

• Hypertonic

• Hypotonic

• Isotonic

Multiple Choice

The cell below is in a _________ solution.

• Hypotonic
• Hypertonic
• Isotonic

Multiple Choice

What type of solution is this cell in?

• Isotonic
• Hypertonic
• Hypotonic
• diffused

Multiple Choice

Which Type of solution is the middle cell placed in?

• Hypertonic

• Hypotonic

• Isotonic

• Robotonic