Download Ch 4 study guide review and short answer test answers

#_____Name:________________________ Date:__________________ Period_____
CHAPTER 4 Review Study Guide-KEY
PART 1: Understanding the Cell Membrane
1. I can draw the structure of a cell membrane using the underlined words in number 2.
2. I can explain why the cell membrane is a good barrier and semi-permeable using words like
phospholipid bilayer, hydrophilic heads and hydrophobic tails.
3. I can explain the role of carrier proteins and ion channels in the cell membrane and how they provide
doorways/passage ways for molecules to pass through.
Ion channels= moves charged particles called ions, and
carrier proteins allow larger molecules like salt and sugar to pass.
(FREE PASS: Water, Oxygen, and Carbon Dioxide have a special ability to go back and forth as much as they want.)
PART 2: UNDERSTANDING how molecules move by Passive Transport
1. I can explain Passive Transport.
(Passive Transport describes the natural process of molecular movement from a HIGH to a LOW concentration,
thus moving WITH or DOWN a CONCENTRATION GRADIENT, and NO ENERGY is needed because it goes with
nature’s laws.)
2. I can list and describe 3 types of passive transport.
(Simple diffusion, Osmosis, Facilitated Diffusion)
1. Simple diffusion- applies to any molecule moving from a high to a lower concentration without the use of
energy. (example: spraying perfume, gas exchange in the lungs, food coloring spreading through water in
a cup.)
2. Osmosis- is the diffusion of WATER molecules across a semi-permeable cell membrane to dilute a high
solute (salt) area.
2b. I can explain the terminology used for solutions in relation to inside cells (Solute, Solvent,
Solution, hypertonic, isotonic, and hypotonic solutions.
1. Solute= what is dissolved (like lemonade “mix”) or (salt or sugar)
2. Solvent= what does the dissolving (like water)
Add them together and you have a Solution (like lemonade)
•A hypertonic solution is HIGH is Solute (thus lower in free water)
•A isotonic solution is about balanced/equal on each side of a membrane.
•A hypotonic solution is LOW in Solute (thus higher in free water)
2c.Solving Osmosis Questions or Scenarios-First, decide which side of the membrane is
higher in solvent (like salt), then second, determine the direction the water molecules can
cross the membrane to “help” dilute the higher solute side.
•Know if cells are placed in a HYPERtonic solution, they will “shrink like a hyper active kid”
because the water leaves the cell in attempt to dilute the high solute solution.
•Know if cells are placed in a ISOtonic solution, water goes back and forth slightly as it keeps
the cell at equilibrium.
•Know if cells are placed in a HYPOtonic solution, they will “swell like a Hippo!” because the
high water content in the solution crosses the cell membrane in attempt to dilute the higher
solute(salt) content inside the cell.
3. Facilitated Diffusion- is the third type of passive transport. It is the process of larger molecules like,
sugar, moving across a semi-permeable cell membrane from a HIGH to a LOW concentration. The same
carrier proteins can be used as in Active transport, but here the molecules follow nature’s law of going
from a HIGH to a Low without Energy.
PART 3- UNDERSTANDING HOW MOLECULES MOVE BY ACTIVE TRANSPORT
1. I can explain the process of active transport. Active requires molecules to move AGAINST the
concentration gradient from a LOW to a HIGH concentration, thus energy is needed!
2. I can list and explain the 3 types of Active transport by either using:
A. Carrier Proteins (#1) or B. Vesicle (#2 & 3):
A. Use of Carrier proteins like a
1. sodium potassium pump
B. Or use of vesicles like in:
2. Endocytosis- (Process of molecules ENTERING the cell in vesicles pinched off from the cell
membrane bringing things into the cell. There two types)
(2 types of endocytosis are: Pinocytosis is a cell drinking and Phagocytosis is a cell eating)
3. Exocytosis- (Process of molecules leaving the cell in vesicles pinched off from the cell
membrane.)
1. Draw a phospholipid membrane of a cell with a protein channel. Label the parts with the following
words: HEADS=hydrophilic(water loving), TAILS=hydrophobic (water hating), carrier/protein
channels, cytoplasm(inside the cell), outside
2. What is a concentration gradient?
______________________________________________________________________
 Draw in molecules illustrating a high to low concentration gradient down the box, and
indicate with an arrow the direction the molecules want to go.
In passive transport, molecules move from a ______________ to a _____ concentration. This is
nature works. So in describing, passive transport, one would say it is the process of molecules
(against/up or with/down) ___________ the concentration gradient until it becomes “balanced”
reaches equilibrium. Is energy needed for this process?
(Yes or no)____________
how
moving
and
3. What is diffusion? Explain the process of diffusion through gas exchange when you breathe.
Written explanation:
Illustration of process:
(one side=blood; second side=lung sac)
Hint: When you inhale oxygen there is a higher concentration in
your lungs than your blood, so the Oxygen rushes into
your blood to balance it out, and the Carbon Dioxide will
do the opposite, but rushing out of the blood where it has
a high concentration to the lower concentration of CO2 in
your lungs. This is how you magically breathe in oxygen
and exhale carbon dioxide!
Rewrite it here:
4 Fill in the Blanks: OSMOSIS & SOLUTIONS
 Hypertonic: Hyper means (high or low)__________ in solute thus the solution is (high or low) ________ in water compared to the
inside of the cell. Since the solute can’t move across the membrane, the water tries to “help out” by diluting the hypertonic
solution outside the cell, causing the water to (leave or enter) _________the cell making it (swell or shrink) ____________. You can
think of cells in a hypertonic solution as “losing water weight” just like a
_ _ _ _ _ active kid.

Isotonic: (“Iso” means ______________________), so the solute concentrations are __ __ __ __ __ or “balanced” between
the outside solution and inside cell. This causes water to enter the cell then it ______;keeping it in equilibrium.

Hypotonic solution: Hypo means (high or low) ______ in solute. Because the solution is _____ in solute, it is (higher or lower)
________ in water compared to inside the cell. Since the salt can’t move across the membrane easily, the water tries to “help
out” by diluting the more concentrated solution within the cell, causing the water to (enter or leave) _________ a cell, and makes
it (swell or shrink) __________________ like a “_______________”.

If you have a bottle of distilled water, what type of solution would it classify as? _____________________
5. A concentrated salt water solution is called a __________________ solution. How does gargling with
salt water or taking an Epson salt bath illustrate the process of osmosis and reduce inflammation in
your throat or sore muscles?
Written explanation:
Illustration of process:
(HINT:A high salt solution is hypertonic, so there is more water inside your cells than outside. This causes the cells to lose water weight in attempt to
dilute the high salt solution. The loss of the water content causes the inflammation in your throat or muscle cells to go down, thus reducing the pain.)
Rewrite it in your own words and illustrate this on a cellular level.
6. Explain how, through the process of osmosis, it is possible to die from water intoxication. (Hold
your wee for wii contest)
Written explanation:
Illustration of process on a
cellular level.
HINT: When a person drinks an excessive amount of water, in a very short time,
without using the restroom, they create a hypotonic situation in their blood, causing
water to dump into their cells and swell. (Remember- cells swell like a hippo When
Brain cells swell, the pressure in the brain increases and causes headaches, nausea,
and potential death.
Rewrite the explanation above in your own words:
7. How does the process of osmosis in not kill your plants when you water them? You are using a
hypotonic solution just as the case in the water intoxication article, so why doesn’t it kill plants like does
in animals? (Hint: Think about the response of the plant’s large central vacuoles in the cells of a wilted plant, in relation a plant’s
__________________________(an organelle plants have that animals do not.) Answer: cell wall
Written explanation:
HINT: Animal cells will swell and possibly burst because of the
weaker cell membrane, where as plant cells have strong cell
walls, so when water enters the large central vacuoles in the
cells of a wilted plant, it fills up the increased turgor pressure
will press on the sturdy cell wall causing the plant to look
healthy and stand upright.
Rewrite it in your own words.
Illustration of process