Download 2017 Cell Processes Test Study Guide

Name ____________________________ Date _________
2017 Cell Processes Test Study Guide - ANSWERS
1. Define concentration.
Concentration is the amount of a substance in a given area or volume.
2. Define selectively or semi-permeable cell membrane.
A selectively permeable cell membrane controls what enters and
exits a cell.
3. The circle to the right represents a cell that is surrounded by a selectively
permeable membrane. Use circles and squares to represent different
molecules in the cell and beaker.
Show that the cell membrane is selectively permeable.
4. Compare and contrast passive and active transport by completing the
table below.
Transport
passive
active
Purpose
transport
molecules
transport
molecules
Requires energy?
no (biking downhill)
yes (biking uphill)
Concentration
high to low
low to high
Examples
diffusion, osmosis
“good/bad”
molecule;
endo/exocytosis
5. What is homeostasis?
the ability of an organism or cell to maintain a relatively stable internal environment (a
healthy internal balance)
6. Explain the role of diffusion, osmosis, and the cell membrane in maintaining homeostasis.
The cell membrane regulates the passage of molecules into and out of cells to maintain
balance.
It allows the cell to transport what it needs in, and dispose of other substances.
7. Explain what is happening in the diagram below. What is the name of this process?
passive transport – molecules move from high to low
concentration to achieve an equal concentration
* DIFFUSION *
8. Red Onion Lab Draw an onion cell in tap and salt water. Indicate high and low
concentrations of water. Include arrows showing movement of the water molecules.
tap water
salt water
red onion cell in tap water – water molecules enter and exit the cell at an equal rate
by the process of osmosis; the cytoplasm is full (water moves from
high to low concentration)
red onion cell in saltwater – water molecules exit the cell by the process of osmosis;
the cytoplasm of the cell decreases in size (water moves from
high to low concentration)
name the process illustrated above ______________osmosis_________________________
Which part(s) of the cell is (are) affected by exposure to different salinities?
__________________________________________________________________________
9. Use arrows to indicate the direction of molecular movement.
is a molecule that
can pass through the cell membrane
.
A)
B)
out of cell
into cell
10. What would the process be called if the molecule in question #9 was oxygen?
diffusion
11. What would the process be called if the molecule in question #9 was water?
osmosis
12. Summarize what you learned from the Carrot Osmosis Lab.
Tap water resulted in an increase in both mass and circumference of the carrots because water
entered the cells from high to low concentration through the process of osmosis. Exposure to salt
water resulted in a decrease in both mass and circumference of the carrots because water exited the
cells from high to low concentration through the process of osmosis.
13. What will happen to a cell that is: (hint – draw a sketch for each)
a. 20% water if it is placed in a 50% salt solution?
water will enter cell, causing it to enlarge, because the salt solution has a higher
concentration of water
50% salt
20%
water
___50__% water
b. 70% water if it is placed in a 30% sugar solution?
there will be an equal exchange of water into and out of the cell, so the size of the
cell will remain constant
30% sugar
__70___% water
70%
water
14. Name the two processes that are represented below, briefly explain what is happening, and
why it is happening.
Molecules are too large to fit through the cell membrane, so the cell must use energy to
obtain them.
A – endocytosis
B - exocytosis
A
B
15. INITIAL
yellow molecules
blue molecules
FINAL
yellow
green
a. What type of membrane does the baggie represent? Include evidence.
The membrane is selectively permeable because the blue molecules are not able to cross
the membrane, while the yellow molecules were able to enter the bag.
b. Which molecule was able to pass through the membrane? How do you know?
Only yellow was able to cross the membrane, because the color change only happened in
the bag, not in the beaker.
c. What would this process be called?
diffusion
16. What don’t you understand for the upcoming test? What would you like to review?