CELLS REVIEW QUESTIONS
Answer the following questions:
1. What is the function of the lysosome in the cell?
2. What is diffusion?
3. Name 2 differences between prokaryotic and
eukaryotic cells.
4. What is osmosis?
5. What is the function of the cell membrane?
1. WHAT IS THE FUNCTION OF THE LYSOSOMES
IN THE CELL?
-Cleanup crew of the cell
- Small organelles filled with enzymes; will digest
lipids, proteins, and carbohydrates into smaller
molecules for the cell to use
2. WHAT IS DIFFUSION?
-
-
Movement of particles from high concentration to
areas of low concentration
Diffusion requires NO ENERGY ( NO ATP!!!)
3. NAME 2 DIFFERENCES BETWEEN
PROKARYOTIC AND EUKARYOTIC CELLS.
Prokaryotic Cells – DNA floats freely in nucleus, no
nucleus, simple cells, BACTERIA
Eukaryotic Cells – DNA enclosed in the nucleus,
contain a nucleus, more complex than
prokaryotic cells,
 Types: Animals, Plants, Fungi, Protists
4. WHAT IS OSMOSIS?
-
-
Type of Diffusion
Movement of WATER
5. WHAT IS THE FUNCTION OF THE CELL
MEMBRANE?
-
-
Regulates what goes in and out of the cell
The cell membrane is selectively permeable
ACTIVE TRANSPORT
ACTIVE TRANSPORT
Sometimes cells must move material against a
concentration gradient – from *low to high*
•
(It’s sort of like pushing your bike up a hill! – you
need ENERGY to get that bike to the top)

Active Transport requires ENERGY (ATP!!!)


Smaller molecules and ions  carried across the
membrane by proteins that act like energy (ATP!!!)
requiring pumps
Examples: Calcium, Potassium, and Sodium ions
SODIUM-POTASSIUM PUMP
Na- ions are maintained at a lower concentration inside
the cell, and K+ ions are maintained at higher
concentration inside the cell
SODIUM-POTASSIUM PUMP
Active transport by protein molecules of the sodium
and potassium ions is central to  electrical
impulses by nerve cells
The ions are squeezed through the transport
proteins, as the proteins change their configuration
to accommodate their riders

Sodium Potassium Pump ( A Short Animation)
TYPES OF ACTIVE TRANSPORT:
ENDOCYTOSIS
Larger molecules must be transported across the
membrane
Endocytosis  process of taking materials into
the cell by means of “infolding”, or making
pockets, of the cell membrane
ENDOCYTOSIS CONTINUES:
The pocket that forms from the membrane breaks loose
and forms a vacuole
What is the function of the vacuole in the cell?
STORAGE!!!!
Large molecules, like clumps of food, can be
taken in this way
TWO EXAMPLES OF ENDOCYTOSIS:
Phagocytosis  “cell-eating;” extension of cytoplasm
surround particle and package it within a food vacuole
Endocytosis
( a short animation)
Cell engulfs it.
Amoebas use this method of taking in food
TWO EXAMPLES OF ENDOCYTOSIS
CONTINUED
Pinocytosis when cells take up liquid from
surrounding environment.
----Tiny pockets form along membrane, fill with the
liquid, and pinch off to form vacuoles within the
cell
TYPES OF ACTIVE TRANSPORT:
EXOCYTOSIS
When cells release a large amount of material
from the cell
EXOCYTOSIS
* Membrane of the vacuole fuses with cell membrane,
forcing the contents out of the cell*
Exocytosis
The removal of water by contractile vacuole
(AMOEBA) is one example of active transport
REVIEW: ENDOCYTOSIS
VS.
EXOCYTOSIS
Endocytosis Vs. Exocytosis
( a short clip)
1. Requires Energy (ATP!!!)
2.) Takes larger
molecules INTO the cell
3. Two Types: Phagocytosis
and Pinocytosis
1.) Requires Energy (ATP!!!)
2.) Takes molecules
OUT of the cell
OVERVIEW
1. The cell membrane regulates what enters and exits the
cell. The cell wall provides support and protection.
2. Particles move from an area of high concentration to an
area of low concentration. This process is called diffusion
OVERVIEW
3. Osmosis is the diffusion of water through the
selectively permeable membrane
4. The cell membrane is double layered and is made
out of phosopholipids, that is where it gets one of its
names: “the phospholipid bilayer”
OVERVIEW
5. Phagocytosis – extensions of the cell
membrane surround a particle and package it
within a food vacuole
6. Pinocytosis – tiny pockets form along cell
membrane, fill with liquid, and pinch off to
form vacuoles inside the cell
OVERVIEW
7. Active transport requires energy (ATP) but
diffusion does not require energy (ATP)
Now: Using the Notes just given to you
and your knowledge of cells complete the
“Outlining the Notes” worksheet
What you do not complete will be
homework. It is due TOMORROW 12/3