Guided Reading 7-3 Key
Protein Marker with a
Carbohydrate Chain
Lipid
Bilayer
Protein Channel
1. Name two functions of the cell membrane:
Controls what enters and exits the cell, provides protection and
support
2. The cell membrane contains protein molecules that are
embedded in the lipid bilayer.
3. Why do scientists call the membrane a "mosaic"? It is made
of many different things, proteins, phospholipids, cholesterol
5. What three types of organisms have cell walls? plants, fungi,
bacteria
6. What is the main function of the cell wall? to provide support
and protection to cells
7. What are plant cell walls composed of? cellulose
8. One of the most important functions of the cell membrane is
to regulate the movement of dissolved molecules from the
liquid
on one side of the membrane to the liquid on the other.
9. A solution is a mixture of two or more substances.
10. Define diffusion: when particles, such as solids and gases,
move from an area of higher concentration to an area of lower
concentration
11. When the particles are the same throughout, the system has
reached equilibrium
12. Diffusion depends on random particle movements, therefore
it [ does | does not ] (circle) require energy.
13. If a substance is able to diffuse across a membrane, the
membrane is said to be _permeable______________
14. Define osmosis: ____the movement of water from a high
concentration to a low________________________
15. Isotonic means __equal concentration_____________
Hypertonic means __more solute_________________________
Hypotonic means ____________less solute________________
16. Because cells are hypertonic in relation to fresh water,
___osmosis________________________ produces a net
movement of water into the cell. If that happens, the cell will
become ___swollen_________________________ and can
even burst.
17. In plant and bacteria cells, what keeps them from bursting
due to osmotic pressure? __cell walls_________
FACILITATED DIFFUSION
18. Cell membranes have protein channels that make it easy for
certain molecules to cross the membrane.
19. When proteins help molecules move across the membrane,
it is called facilitated diffusion
ACTIVE TRANSPORT
20. Active transport moves molecules [ with | against ] the
concentration gradient.
21. Active transport requires cell energy
22. Changes in protein shape seem to play an important role in
the transport process.
23. Define endocytosis: when a cell takes in materials through
infoldings or pockets in the cell membrane
24. What are the two types of endocytosis? pinocytosis and
phagocytosis
25. How does an amoeba gets it food? phagocytosis
26. Cells release large amounts of material in a process called
exocytosis