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Chapter 3 Review Guide
The Plasma Membrane
1. What is the function of the plasma membrane?
Contains the contents of the cell / provides a boundary for the cell / controls what gets into and out of the cell
2. There are four major components to the plasma membrane listed below.
a. Phospholipid
i. What is the general structure of the phospholipid?
Glycerol molecule with two fatty acid tails and one phosphate group
ii. What chemical properties does the phospholipid have?
Phosphate group is polar and hydrophilic / Fatty acid tails are nonpolar and hydrophobic
iii. How are phospholipids arranged in the plasma membrane?
The polar “heads” face the watery environment (inside and outside) while the nonpolar tails
face each other away from the watery environment.
b. Proteins
i. What is the function of these proteins in the membrane?
To help transport materials from one side of the membrane to another
ii. What are the two basic types of proteins found in the membrane called?
Channels – help materials move from high to low  facilitated diffusion
Pumps – with energy move materials from low to high  active transport
c. Carbohydrates
i. What is their function for the cell?
Signal materials on external side of cell
d. Cholesterol
i. What is their function in the cell membrane?
Stabilize the membrane
3. What does a fluid mosaic model mean as a way to describe the plasma membrane?
The membrane is a representation of a boundary composed of many small pieces that are constantly in motion
4.
What are the items that can easily pass through the phospholipids of the membrane?
Small polar molecules, non-polar substances
5. What are the items that pass through the proteins of the membrane?
Large molecules, ions
6. What does it mean that the plasma membrane is selectively permeable?
The membrane selects what can pass through the membrane and what can’t
Transport
7. In order for transport to happen, there must be a Liquid inside and outside of the cell.
8. There are two different types of transport – passive transport and active transport. Passive transport is the
movement of materials from an area of HIGH concentration to an area of LOW concentration WITHOUT the use
of energy. Active transport is the movement of materials from an area of LOW concentration to an area of
HIGH concentration WITH the use of energy.
9. There are three types of passive transport – diffusion, osmosis, and facilitated diffusion.
a. Diffusion
i. What is transported in diffusion? solutes
ii. What are some things that can affect the rate of diffusion? Pressure, temperature,
concentration of solute, agitation
b. Osmosis
i. What is transported in osmosis? water
ii. Why does osmosis happen? Because the solutes can’t move due to selectivity of membrane
iii. What is the difference between a hypertonic solution, a hypotonic solution, and an isotonic
solution? Hypertonic solutions cause cells to lose water, hypotonic solutions cause cells to gain
water, isotonic solutions cause water to move equally across the membrane
iv. What is the difference between lysing and plasmolysis? Lysing is popping a cell, plasmolysis is
the shrinking of a cell
c. Facilitated diffusion
i. What is transported in facilitated diffusion? Large molecules, ions
ii. What is helping (or facilitating) diffusion happen? Protein channels
10. Active transport can happen through the membrane proteins or it can be a rearrangement of the membrane
itself.
a. If active transport happens through the membrane proteins, in what form is the energy that is used to
pump the molecules across the membrane?
ATP
b. If active transport involves the rearrangement of the membrane and substances are being brought into
the cell, what is the process called? Endocytosis
i. What is the difference between pinocytosis and phagocytosis? Pino – liquid droplets, phago –
solid chunks
c. If active transport involves the rearrangement of the membrane and substances are being exported out
of the cell, what is the process called? exocytosis
Respiration
11. The respiratory system is composed of several different parts working together as a whole organ system. The
structure of each part relates to its function.
a. Trace the flow of air through the respiratory system starting at the nostril and ending where transport
happens.
Nostril > nasal cavity > pharynx > larynx > trachea > bronchi > bronchiole > alveoli
b. Once the air enters the lungs (and reaches its final “resting place”), explain what transport is happening
to the different molecules?
Diffusion of oxygen from alveolar air space into the blood and diffusion of carbon dioxide from blood
into alveolar air space
c. Describe the process of breathing – how does it happen?
The contraction of the diaphragm and intercostals muscles expands the rib cage creating a low pressure
environment compared to the outside – this causes air to rush into the lungs. When the diaphragm and
the intercostals muscles relax, the rib cage gets smaller creating a high pressure environment compared
to the outside – this causes air to leave the lungs
d. Compare our respiration to:
i. Single cells / simple invertebrates simple diffusion into the water
ii. Fish / Organisms with gills counter current flow between blood in the gills and the water over
the gills
iii. Worms / Slugs gases dissolve in mucous surrounding worm/slug then diffuse into organism
iv. Insects air enters and leaves holes on the side of the body called spiracles – air circulates in the
body when the insect is moving
v. Birds air enters into a set of air sacs which then feeds the lungs – the carbon dioxide rich are
leaves the lungs and moves through more air sacs to out of the body – allows for oxygen rich air
and oxygen poor air to stay separate
e. What were some problems mother nature had to deal with when moving life from water to land?
Keeping exchange surface moist without losing too much water in the process
Excretion
12. Explain the similarity and differences of ammonia, urea, and uric acid. Why do these differences exist?
Similarity – all are toxic results of protein metabolism
Differences – Ammonia is most toxic and requires most amount of water to eliminate; urea is less toxic and
requires a lesser amount of water to eliminate; uric acid is the least toxic and requires the least amount of water
to eliminate
13. The excretory system is composed of several different parts working together as a whole organ system. The
structure of each part relates to its function.
a. Trace the flow of filtrate through the nephron after it leaves the glomerulus until it gets to the bladder.
Bowman’s capsule > proximal convoluted tubule > Loop of Henle > distal convoluted tubule > collecting
duct > ureter > bladder
b. What types of transport happen in the nephron as the filtrate moves from beginning to end? Explain
what is actually being transported and where in the nephron that it is happening.
Mechanical pushing of materials out of the blood vessels due to high blood pressure (glomerulus into
Bowman’s capsule)
Diffusion of “good” materials from proximal convoluted tubule and loop of Henle back into blood
Osmosis of water in loop of Henle and distal convoluted tubule
Active transport of salts in loop of Henle and distal convoluted tubule
c. After the urine leaves the kidney, trace the flow of urine through the rest of the trip it would take.
Kidney > ureter > bladder > urethra
1. Know the structure of the membrane and how its structure serves its function, makes it selectively permeable. How
do the phospholipids and the proteins in the membrane do this?
The chemical properties of the phospholipids allow small, polar molecules and small, nonpolar molecules to pass
through the lipid bilayer. Ions and larger, polar molecules are repelled. In order for the ions and the larger, polar
molecules to pass across the membrane, the proteins must be used. The carbohydrates on the membrane are used as
signals to “attract” cell-specific materials. The cell membrane will select what it wants inside the cell based on all of the
above characteristics.
2. Label the situations below as active transport, facilitated diffusion, simple diffusion (through phospholipids) or
osmosis:
A. the movement of oxygen and carbon dioxide molecules into and out of bloodstream from alveoli diffusion
B. pushing out of proteins made by the cell in a vesicle exocytosis (active transport)
C. Plant cell swelling and becoming turgid (bulging of the cell wall) osmosis
D. Sodium ions in high concentration outside the cell moving into the cell diffusion
E. The rupturing of an animal cell place in pure water osmosis
F. the secretion of additional potassium into the nephron due to chemical signaling of aldosterone active transport
3. Be able to solve transport situational problems:
CELL: 20%
If the membrane is permeable to sucrose
What is going to happen?
sucrose
Sucrose will move into the cell
If the membrane is NOT permeable to
sucrose what is going to happen?
water will move out of the cell and the cell will shrink
Outside cell:
40% sucrose
Intravenous solutions (IV) must be prepared so that they are isotonic to red blood cells. A 0.9% salt solution is
isotonic to red blood cells.
a. Explain what will happen to a red blood cell placed in a solution of 99.3% water and 0.7% salt.
water will move into the cell
b. What will happen to a red blood cell placed in a solution of 90% water and 10% salt? Water will
move out of the cell
Draw images to support your answer.
Iso
A (Hypotonic)
B (Hypertonic)
4. Know the basics of respiration (no diagram to label)
How is gas exchange a mechanism for homeostasis?
Maintains blood pH by getting rid of the carbon dioxide via the lungs and pulling in oxygen (to help provide energy)
Adaptations from water to land: pull respiratory surfaces inside the organism to reduce water loss (due to large surface
area)
Adaptations in birds for flight: air sacs allow for air to not mix so birds get maximum amount of good air
Why do our lungs divide into many, many tiny air sacs rather than just one large air sac? Increase surface area
Know how gases are transported from lung to blood and from blood to lung (see previous answer in #2) diffusion of
oxygen from lung to blood, diffusion of carbon dioxide from blood to lung
5. Know how the kidneys work and how they function in homeostasis:
1
Label the parts in the diagram :
Place a 1 where filtration occurs.
Place a 2 where reabsorption occurs.
Place a 3 where secretion occurs.
3
Define all three terms: filtration,
reabsorption
and secretion.
Know what kind of transport is occurring at
different points within the nephron
(hint: passive transport, active transport and
osmosis ALL happen in the kidney).
3
2
2
Review lab 3C!
FILTRATION – the pushing out of materials from the glomerulus
REABSORPTION – the diffusion, osmosis, and active transport of metabolically important materials back into the
blood from the proximal tubule, Loop of Henle, and distal tubule
SECRETION – the removal of waste from the nephron
Filtration
 Blood pressure forces materials out of the glomerulus into Bowman’s capsule
 LARGE MOLECULES NEVER LEAVE THE BLOOD
Reabsorption
 Small sugars, amino acids, and other small molecules diffuse back into blood
 Water will move via osmosis
 Active transport will move ions back into the blood - aldosterone
Secretion
 Osmosis will continue or stop depending on amount - ADH