Download Chapter 7 Review Sheet

Exam 3 – Quarter 2 Review Sheet
AP Biology
Exam 3 will cover:
1. Chapter 7 Mats ALL
Water Potential Problems
The Cell Membrane (animations under misc section)
1. Describe the structure of a phospholipid in detail and be able to draw it. Just use R for
the group attached to the phosphate, but do not forget the charge.
2. Indicate how phospholipids align relative to each other in an aqueous solution (we
discussed two ways), explain WHY they do this (water cage…random collision…etc…),
and be able to draw both. Which of these ways is representative of a cell membrane.
3. Describe the structure of a cell membrane. What are they composed of and how are
they organized? Be able to draw a two-dimensional membrane that includes all types of
integral membrane proteins discussed in class, peripheral membrane proteins,
glycoproteins, glycolipids, ECM, cytoskeleton, and cholesterol. For example, I could ask
you to draw a membrane containing all these items and shows three different classes of
integral membrane proteins in terms of function (transport, enzyme, receptor, etc…).
4. Identify functions of glycosylated integral membrane proteins.
5. Identify the general functions of integral membrane proteins and give real-world
examples of each.
6. Explain the terms ligand and receptor.
7. Identify and describe the three general phases of cell signaling – reception, signal
transduction and response.
Watch the tutorial below and use it to explain cell signaling beginning with a hydrophilic
(amino acid/polypeptide/protein) hormone.
http://bcs.whfreeman.com/thelifewire/content/chp15/15020.html
This tutorial is under misc section of website.
This specific pathway, which is triggered by adrenaline (epinephrine) released from the adrenal medulla or
the adrenal gland in response to some fight or flight external stimulus (ex. A bear chasing you). Adrenaline
is a amino acid based hormone. This particular animation does not show genes being turned on and off, but
remember that they usually are in response to a hormone signal.
8. What is the difference between a ligand and a substrate?
9. Describe the functions of cell membranes. You should be able to come up with many.
10. A) Explain what is means that cellular membranes are selectively (semi-) permeable.
B) Describe the types of substances that can and cannot cross the plasma membrane
without the aide of proteins. C) Explain WHY a steroid like testosterone can cross by
simple diffusion, while a much smaller substance, Na+, cannot cross. This must be in
detail…a logical, rationale reason… D) Explain why large substances like polymers,
regardless of charge/polarity, cannot cross.
11. Using the analogy of the cell, how thick is the cell membrane? What is the actual
thickness is nm?
12. Describe the fluid mosaic model of membranes. What does “fluid” and what does
“mosaic” refer to? The inner life of the cell video shows this nicely.
13. Explain the ABO blood types in detail. What is the molecular difference between
these blood types and why does this molecular difference arise?
14. Explain why I always say that being inside the ER/Golgi is like being outside the cell.
15. Explain the function of cholesterol in the membrane. How does it act as a “fluidity
buffer” – what is it doing at elevated temps…at low temps?
16. Explain why it is rare for a phospholipid to flip from one leaflet to another, but
frequent that it moves laterally.
19. The membrane spanning region of most proteins is what secondary element? The
amino acids in these regions tend to be of what type? Explain why membrane proteins do
not slip out of the membrane.
20. 7TM-GPCR…what does this stand for and what type of protein is this?
Simple Diffusion (simulator under misc section)
1. Describe the process of diffusion on the molecular level. Why do substances diffuse
from “high to low concentration”? Include random motion and probability in your
explanation. Do not just say high to low concentration.
2. What is meant when one says that diffusion is “passive”? Explain why it is passive.
3. Explain how concentration gradients relate to diffusion. What is a concentration
gradient? What does it mean to move down the gradient? Up/Against the gradient?
Passive Transport – Diffusion (tutorial under misc section)
1. Explain passive transport (Be able to explain Figure 5.14). Remember that once we say
“transport” we are implying across a cellular membrane.
2. Make sure you understand the difference between the actual movement of molecules
across a membrane and the NET movement of molecules across a membrane.
3. What is meant by “dynamic equilibrium”? What is happening during dynamic
equilibrium and why does this happen? (again…probability and likelihood) Why is it
called “dynamic” “equilibrium”?
4. Explain why when two different substances are placed on either side of a semipermeable membrane they diffuse independent of each other assuming they do not bind.
5. What is osmosis?
6. Explain the process of osmosis in terms of a U-tube.
7. Compare hypertonic, hypotonic and isotonic solutions. Why can’t a solution be one of
these types if it is the only solution you have?
8. Explain why water tends to diffuse from hypotonic to hypertonic solution.
9. Make sure you can do the problems in the powerpoint.
9. What does osmoregulation mean and give two examples in nature. Why is it important
that our bodies are able to perform osmoregulation?
10. Compare and contrast what would happen to an animal cell vs. a plant cell when each
is placed in a isotonic solution, hypotonic solution, or hypertonic solution. You should be
able to explain why this happens on the MOLECULAR LEVEL in terms of concentration
gradients, probability, why the solutes don’t just cross the membrane instead of the water,
etc… Put the big picture together.
12. You should know the terms crenate and plasmolysis and the cell types they refer to.
In which of the three states in this figure are plants most happy? What about animal cells
(most happy)?
13. Explain why if you drink salt water your brain will inform you that you are thirsty.
What is happening to your blood and why would you need to drink water to help
yourself? Also tell me why if you ever get an IV at the hospital the fluid is 0.9% NaCl
(0.9g per 100ml of water). If you were going to make an eye drop solution for people
with contacts, what salt concentration do you think you would use?
For more info read here:
http://en.wikipedia.org/wiki/Saline_%28medicine%29
14. Explain what would happen to a fresh water fish if you put them into a saltwater
aquarium and why?
15. Explain WHY the concentration of solute molecules in a solution is more important
than the actual number of solute molecules. Thinking about collision theory will help (if
you do not know what collision theory means, look it up).
10. Compare and contrast what would happen to an animal cell vs. a plant cell when each
is placed in a isotonic solution, hypotonic solution, or hypertonic solution. You should be
able to explain why this happens on the MOLECULAR LEVEL in terms of concentration
gradients, probability, why the solutes don’t just cross the membrane instead of the water,
etc… Put the big picture together.
11. WATER POTENTIAL!! Make sure you understand water potential as it relates to
osmosis, solute potential and physical potential. Be able to calculate water potential and
fill in hypothetical numbers for different scenarios - plant cell placed in hypotonic
solution or plant cell placed in hypertonic solution as done in class. Be able to do the Utube questions on the powerpoint!
12. You should know the terms crenate and plasmolysis and the cell types they refer to.
In which of the three states in this figure are plants most happy? What about animal cells
(most happy)?
http://en.wikipedia.org/wiki/Collision_theory
Passive Transport – Facilitated Diffusion (tutorial under misc section)
1. Explain how a cell moves small hydrophilic molecules across its membrane? What is
the name of this type of passive transport? Why can’t small hydrophilic molecules cross
the membrane without assistance?
2. Identify the two general types of facilitated diffusion proteins and explain how they are
different.
3. Identify and describe the three different ways that a membrane channel can be
regulated. Be specific. For example, how do voltage-gated channels work?
Active Transport (tutorial under misc section)
1. Compare and contrast passive to active transport.
2. Draw the structure of ATP? How is it related to active transport (what is the function
of ATP)? Explain why ATP has the ability to accelerate matter. Why do I usually refer to
ATP as a loaded gun? Does ATP have a high or low affinity for its third phosphate?
3. Explain in detail how the sodium-potassium pump works. The result of such a pump is
an electrochemical gradient. Explain what this is and why it results.
4. After ATP has donated its phosphate to a protein or other substance, it becomes ADP.
If this happened without the reverse reaction, you would run out of ATP in seconds and
die. How does the cell, in very general terms, get that phosphate back on ADP to make
ATP again so that you can keep fueling your proteins?
5. What is the term we use to describe the addition of a phosphate onto a substance?
What type of enzyme will do this? What do we call the removal of a phosphate from a
substance?
6. Explain how large molecules enter and exit the cell. Is this active or passive transport.
Explain.
7. You should still be able to go from a gene on a chromosome in the nucleus to a protein
secreted from the cell via the endomembrane system (exocytosis).
8. You should be able to describe the three types of endocytosis discussed in class and
how they differ from each other. Which is the most specific? Explain. Which uses
pseudopods and why not just pinch in? Which use ATP?
9. Why would a cell want to perform endocytosis in general? Where does the vesicle with
the ingested material first go? Explain why. Your white blood cells will do endocytosis of
bacteria, bacterial parts and your own dead cells to clean up and recycle. Explain.
10. Describe the structure and function of LDL’s. If your blood contains too high a
concentration of LDL’s, describe how your liver can reduce the concentration.
11. Explain the disease hypercholesterolemia and what it could lead to on the molecular
level.
12. Describe how co-transport works and give an example.
13. Be able to explain how blood types work. What genes are behind the different types
and what is the resulting phenotype (physical appearance of the cell) in terms of
polysaccharides.
14. I am getting tired and I need to write the test. All bold words in chapter and do
questions in chapters as well if you didn’t do it already because they were assigned for
homework.
STUDY WELL