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Cells Unit Study Guide
Biology
Cell Unit Study Guide
1. List some difference between prokaryotic and eukaryotic cells.
eukaryotes
•
•
•
•
•
•
Much larger
Much more complex
Contain a true nucleus to house the genetic material (DNA)
Linear DNA packaged into chromatin found inside the nucleus
Contains specialized structures in the cytoplasm called organelles to carry out various functions
Not all have a cell wall
prokaryotes
•
•
•
•
•
•
Much smaller
Less complex
No true nucleus
Circular DNA that is found in the cytoplasm
No organelles found in the cytoplasm
Surrounded by a cell wall
2. Organelle means "little organ." How are organelles similar to organs?
-they have a specific structure and function to carry out a specific job- just like
organs in our bodies
3. What are the levels of organization in a eukaryote?
- list them.
-cell, tissue, organ, organ system, organism
4. All large organisms have cells with organelles. What advantage do
organelles give the cell?
Eukaryotic cells are larger and can not pass nutrients as quickly. They require
specialized organelles to:
i. carry out metabolism
ii. provide energy
iii. transport chemicals throughout the cell
5. The cell requires instructions in order to function correctly; where
are these instructions found? - the DNA in the cytoplasm
6. How are the functions of mitochondria and chloroplasts similar? Which
kinds of cells can each be found in?
-they both provide energy for the cell
-mitochondria in all types of cells – chloroplasts are only in plant cells
7. By comparing a bee's body mass to its wing span, it has been
calculated that a bee should not be able to fly. Cell biologists have
since found that the muscles which control the wings of the bee have
a huge number of mitochondria. Explain why this discovery may help
explain why bees are able to fly.
-the mitochondria provide energy for cells- the cells of a bee’s wings must
be able to have ample amounts of energy needed to operate.
8. What is the function of the ER?
Location:
Function:
In the cytoplasm around the nucleus
Modifies materials needed in the cell
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Cells Unit Study Guide
Biology
Aka:
“Fashion designers”
9. Describe the function of the Golgi apparatus.



Location: In the cytoplasm
Function: Sorts and ships materials to the correct parts of the cell
Aka: “the post office”
10.



What is the function of the ribosome?
Location: In the cytoplasm and on the rough ER
Function: Makes protein
Aka: “Protein packs”
11.
Cells of the stomach lining have large numbers of ribosomes and
Golgi. Explain why this is true.
Golgi Function: Sorts and ships materials to the correct parts of the cell
ribosomes: Function: Makes protein
The stomach is a major site of digestion. Food material needs to be absorbed in the cells and packaged to be sent wherever
it needs to go throughout the cells of the body.
12.



What are the functions of lysosomes?
Location: In the cytoplasm
Function: Destroys worn out cell parts
Aka: “the death chamber:
13.
A Biology student has observed an amoeba (animal cell) and made
a drawing. You are marking the drawing and notice that he has drawn
in a chloroplast. Do you take marks off or not? Explain.
– an amoeba is an animal cell, and therefore does not have any chloroplasts
14.
What is the function of the cell wall?
organisms that have cell walls.



Name some types of
Location: Around the cell membrane of plant cells
Function: Gives the cell shape and protection
Aka: “plant cell armor”
 ex: oak tree, apple tree, apples, onions, leaves of any type
15.
How does a cell membrane differ from a cell wall?
-materials can pass through a cell membrane- it determines what can come into and
out of the cell; both plant and animal cells have a cell membrane
-cell walls provide support and protection for the cell- only plant cells have them
16.
List the organelles that are only found in plants. List those
found only in animals.
found only in plants: cell wall, chloroplasts
only in animal cells: cilia, flagella
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Cells Unit Study Guide
Biology
The Cell Membrane
Diffusion is the movement of particles from areas of higher concentration to areas of lower concentration. It is a natural, random
process. This means that it does not require extra energy input.
1a. These are pictures of molecules frozen at two different times. Draw arrows to show the direction each particle might travel
due to diffusion in diagrams A and B.
A.
B.
Random arrows
Random arrows
1b. Describe the way the particles of a gas move.
Randomly
1c. Diagram A shows the same number of particles as in Diagram B except most particles start out on one side of the box. Explain
why after a while, Diagram A resembles Diagram B.
Molecules move randomly and reach equilibrium
2. Give an everyday example of diffusion in air and in water.
AIR: e.g. Scents and Smells
WATER: e.g. Colored dye in a glass of water
3. Complete the following sentence: Diffusion is the -Random- movement of particles from -High- concentration to a -Lowconcentration until they are Evenly spread out.
4. Moths emit chemicals called pheromones to attract a mate.
a) Which process is responsible for the distribution of these chemicals through the air?
Diffusion
b) If a moth detects pheromones, how might it work out which direction they are coming from?
Detect the higher concentration of pheromones
c) What would be the advantage of a moth releasing the pheromones on a night when there was little wind?
The pheromones aren’t blown away from a potential mate
5a. Osmosis is the diffusion of water across a semi permeable membrane. The semi permeable membrane acts like a filter that
lets only the water through. Water always goes from the area of higher water concentration to the area of lower water
concentration. Confused? Then imagine the particles (or solute) are salt and follow the rule - SALT SUCKS!
On the diagram on the next page label the:
• Semi permeable membrane (M)
• Area of higher water concentration (HC)
• Area of lower water concentration (LC)
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Cells Unit Study Guide
Biology
• Direction of osmotic flow (arrow)
M
LC
HC

5b.






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What happens to the number of water particles on the left hand side?
Increase
What happens to the concentration of the solution on the right hand side?
Stays the same
What happens to the concentration of the solution on the left hand side?
Decreases
Explain why the concentrations of solution on either side of the semi-permeable membrane change?
Water passes through the membrane until in equilibrium, the Salt does not
6. Complete the following sentence: Osmosis is the passage of Water molecules from a LOW concentrated solution to a HIGH
concentrated solution through a Semi permeable Membrane
7. The roots of a plant have root hair cells that absorb water from the soil. The diagram below shows two different kinds of roots.
The concentration of the solution inside the cell is higher than the concentration of the solution in the soil.
a) Explain why water moves from the soil into the root hair cell.
Water equilabrates through the semi permeable membrane moving from a high concentration of H20
outside to a low concentration of H2O inside the cell
b) Suggest why root hair cells are long and thin and not short and stubby?
More membrane surface area so more water can be taken up by the plant.
8. Label the following diagrams of Red Blood Cells and Plant Cells as being examples of cells contained in Isotonic, Hypertonic
and Hypotonic solutions.
Hypo
Iso
Hyper
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Cells Unit Study Guide
Biology
9. Strawberry jelly is a very strong solution of sugar. By contrast the cytoplasm in a bacteria is a
Much weaker solution.
(a.) The cell wall of a microbe is made up of a semi-permeable membrane. Would water flow from the microbe to the jam,
or from the jam to the microbe by osmosis?
Microbe to Jam
(b.) Explain why bacteria find it difficult to survive in jam.
They can’t keep water inside of their cell which they need for their metabolism.
10. Why is a cell membrane considered “selectively permeable”?
The cell membrane controls what, when, and how materials can pass
through the membrane
11. What is the function of proteins in cell membranes?
• Proteins act as passageways for nonpolar (hydrophobic) molecules to
pass through.
• Without proteins embedded in the bilayer, essential molecules needed
for communication, energy, etc., would not reach the interior of the
cell.
12. What is the function of carbohydrates (such as cholesterol) in cell
membranes?
•
Carbohydrates are attached to the proteins.
– Allow for cell recognition and communication.
13. What is active transport?
– the movement of molecules through a cell membrane using energy
14. If a substance cannot be passed through the cell membrane via osmosis
or diffusion, how is it still able to be moved into or out of the cell?
Facilitated Diffusion - Diffusion through pores or channel proteins
15. When would the cell perform:
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Cells Unit Study Guide
Biology
Endocytosis: process of cells engulfing large particles by forming a
vesicle around them
Phagocytosis: (cell eating)
- If the particles are cell fragments or organic matter
Pinocytosis: (cell drinking)
-occurs if the particles have been partially broken down into a
liquid of tiny dissolved
molecules
Exocytosis: -process by which wastes or secretions (hormones) are
brought to the cell
membrane, packaged into vesicles and sent out
of the cell
– the reverse of endocytosis
16. What is a receptor? How does it allow cells in multicellular
organisms to communicate?
• are often found on the outside of cells where they bind chemical
signaling molecules and influence cellular activity.