CELL MEMBRANE DAY TWO (H)
Objective: Today we will identify the main functions of the cell membrane, describe what happens during
diffusion and explain the process of osmosis.
Warm Up: Answer ALL of the questions below
1. What is the main function of the cell membrane?
2. What does the term “homeostasis” mean?
3. What role does the cell membrane play in the process of maintaining homeostasis within a cell?
Cell Membrane
Notes


Cell membranes of unicellular organisms are ____________ so the organism can move.
What is meant by homeostasis?

Homeostasis is also called __________________.

How does the plasma membrane help maintain homeostasis?

Give 5 functions of the plasma membrane.
a.
b.
c.
d.
e.

What is meant by the term selectively permeable?

Fluid inside the cell is called _________________.

Label the plasma membrane

A ________________ bilayer makes up most of the cell membrane.

Are phospholipids heads polar or nonpolar? the tails?

How many fatty acid chains are in a phospholipid? _______

Describe the heads of a phospholipid.

The __________ _____________ ___________ describes the appearance of the cell membrane.

Why is the cell membrane said to act like a fluid?

What causes the mosaic pattern of the cell membrane when viewed from above?

The phospholipid ________________ of the cell membrane allows _______________ molecules to pass
through easily, but _________________ do NOT.

Materials soluble in __________ can pass easily through the cell membrane.

Because the cell membrane is ___________________, only ___________ molecules and larger
_______________ molecules can move through easily.

List 3 substances that pass easily through the cell membrane.


2.
3.
_________, _____________ molecules larger than water, and large __________ molecules do NOT
move easily through the phospholipids of the cell membrane.

Simple ____________ requires NO energy to move things across the cell membrane.

With simple diffusion, molecules move from an area of ________ concentration to an area of ______
concentration.

Why is diffusion considered a passive process?

With diffusion, molecules move by their own natural __________ energy or energy of motion.

Explain what happens to a drop of food coloring put into a beaker of water.


When solutes diffuse through a membrane, they move from __________ to _________ concentration.
__________ is the diffusion of _________ across a cell membrane.

If water potential is HIGH, solute concentration is __________.

If water potential is LOW, solute concentration is ___________.

Water moves from _________ water potential to ________ water potential.

Water diffuses through the pores called _____________ of the cell membrane.

Sketch a picture of a cell in an isotonic environment & show the direction of water movement?

What is meant by NO NET movement?

Sketch a picture of a cell in a Hypotonic environment & show the direction of water movement?

Sketch a picture of a cell in a hypertonic environment & show the direction of water movement?

Complete the following table:
Environmental
Condition
Hypotonic
Hypertonic
Isotonic
Direction of Osmosis
Net Movement of
water
What happens to cell

_____________ occurs whenever water moves out of a cell & the cell shrinks in size.

_____________ occurs whenever water moves into the cells causing them to swell and burst.

Explain what happens to a red blood cell placed in:
a) distilled water
b) a concentrated salt solution

Complete the following drawings.

Passive transport does _______ require additional energy & moves materials from ________ to
_________ concentration.

Give 2 examples of passive transport in cells.

___________ diffusion is a type of __________ transport because energy is NOT required.

Facilitated diffusion uses _____________ proteins to help move materials from _________ to
__________ concentrations.

Name 2 materials that move into or out of cells by facilitated diffusion.

Name 2 types of transport proteins found in cell membranes.

Describe channel proteins.

How do carrier proteins help move materials across a cell membrane?

Channel proteins have an opening or ___________ through which molecules can passively move by
_____________ diffusion.

Do all carrier proteins extend across the cell membrane? _____

Explain how these carrier proteins move materials across the membrane.

Some carrier proteins can change ________ to move materials across the cell membrane.

__________ transport requires additional energy to move materials.

Active transport uses cellular energy known as _________.

Active transport moves materials AGAINST the concentration gradient or from _________ to
___________ concentration.

The _______________ pump is an example of active transport.

Moving very large particles out of the cell is called _____________.

In exocytosis, wastes are moved out of the cell in ___________ that fuse with the cell membrane.

__________ involves moving large particles into the cell.

Taking in large liquid droplets is called ____________ or "cell drinking".

"Cell eating" is known as ______________.

White blood cells engulfing bacteria is an example of _____________.

_____________ is the opposite of exocytosis.
Osmosis Worksheet
Closing: I will compare and contrast the processes of facilitated diffusion and osmosis by creating a Venn
diagram that identifies similarities and differences between the two.