Biology Unit 4 Exam: Cell Membrane & Transport
- 1.
When the concentration of molecules on both sides of a membrane is the same, the molecules will
- A.
Move across the membrane to the outside of the cell.
- B.
Stop moving across the membrane.
- C.
Move across the membrane in both directions.
- D.
Move across the membrane to the inside of the cell.
Correct Answer
C. Move across the membrane in both directions.Explanation
Molecules are constantly in motion. At equilibrium, molecules are moving in both directions at the same rate.Rate this question:
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- 2.
Diffusion takes place
- A.
Only through a lipid bilayer membrane.
- B.
From an area of low concentration to an area of high concentration.
- C.
Only in liquids.
- D.
From an area of high concentration to an area of low concentration.
Correct Answer
D. From an area of high concentration to an area of low concentration.Explanation
Diffusion is the movement of any type of molecule from an area of high concentration to an area of low concentration.Rate this question:
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- 3.
Which of the following is a function of the cell membrane?
- A.
Breaks down lipids, carbohydrates, and proteins from foods
- B.
Stores water, salt, proteins, and carbohydrates
- C.
Keeps the cell wall in place
- D.
Regulates which materials enter and leave the cell
Correct Answer
D. Regulates which materials enter and leave the cellExplanation
The cell membrane maintains homeostasis by controlling/regulating cell transport.Rate this question:
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- 4.
The diagram shows a cell membrane composed of a phospholipid bilayer with a channel protein. Each x represents the same type of molecule inside or outside the cell. Facilitated diffusion moves these molecules across the cell membrane. In what direction do these molecules move and through which structure?
- A.
Into the cell through the channel protein
- B.
Into the cell through the phospholipid bilayer
- C.
Out of the cell through the channel protein
- D.
Out of the cell through the phospholipid bilayer
Correct Answer
A. Into the cell through the channel proteinExplanation
Facilitated diffusion is a type of passive transport where molecules move from high concentration to low concentration through a protein channel.Rate this question:
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- 5.
Which of the following structures serves as the cell’s boundary from its environment?
- A.
Mitochondrion
- B.
Cell membrane
- C.
Chloroplast
- D.
Channel proteins
Correct Answer
B. Cell membraneExplanation
The cell membrane and cell wall are the outer boundaries of the cell.Rate this question:
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- 6.
The cell membrane contains channels and pumps that help move materials from one side to the other. What are these channels and pumps made of?
- A.
Carbohydrates
- B.
Lipids
- C.
Bilipids
- D.
Proteins
Correct Answer
D. ProteinsExplanation
The transport channels and pumps in the cell membrane are made out of protein.Rate this question:
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- 7.
Which of the following does NOT use energy?
- A.
Diffusion
- B.
Endocytosis
- C.
Active transport
- D.
A sodium-potassium pump
Correct Answer
A. DiffusionExplanation
Diffusion is passive and does NOT use energy.Rate this question:
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- 8.
Which means of particle transport requires energy from the cell?
- A.
Diffusion
- B.
Osmosis
- C.
Facilitated diffusion
- D.
Active transport
Correct Answer
D. Active transportExplanation
Active transport requires energy. Diffusion, osmosis, and facilitated diffusion are all passive.Rate this question:
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- 9.
When scientists stain natural cell membranes with a heavy metal, they can view the membranes with an electron microscope. The heavy metal stains the polar hydrophilic heads of phospholipid membranes. When viewed under a microscope, would appear stained? (Note: Shading represents stains.)
- A.
![Biology Unit 4 Exam: Cell Membrane & Transport - Quiz]()
- B.
![Biology Unit 4 Exam: Cell Membrane & Transport - Quiz]()
- C.
![Biology Unit 4 Exam: Cell Membrane & Transport - Quiz]()
- D.
![Biology Unit 4 Exam: Cell Membrane & Transport - Quiz]()
Correct Answer
C.Explanation
The polar heads of the phospholipids are on the outside and the nonpolar tails are on the inside (like an oreo cookie).Rate this question:
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- 10.
Proteins are produced by ribosomes, modified by rough ER, and then packaged by the Golgi apparatus. By what process do these packaged proteins exit a cell through the cell membrane?
- A.
Active transport
- B.
Exocytosis
- C.
Facilitated diffusion
- D.
Osmosis
Correct Answer
B. ExocytosisExplanation
Proteins are too large for any other transport, so they are packaged in a vesicle which fuses with the cell membrane. This is called exocytosis.Rate this question:
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- 11.
Refer to the illustration above. The process shown is called
- A.
Osmosis.
- B.
Facilitated diffusion.
- C.
Active transport.
- D.
Diffusion.
Correct Answer
D. Diffusion.Explanation
The solid cube is dissolving in the liquid. The molecules are spreading out from high concentration to low concentration so this is diffusionRate this question:
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- 12.
A scientist places a cell in a solution, and over time the cell gains mass and swells. What is the most likely explanation for the cell’s gain in mass?
- A.
The solution is hypertonic to the cell.
- B.
The solution and the cell have equal concentrations of solutes.
- C.
The solution is hypotonic to the cell.
- D.
The solution and the cell have equal concentrations of water.
Correct Answer
C. The solution is hypotonic to the cell.Explanation
If a cell is placed in a hypotonic solution, water will move into the cell. This would explain the increase in mass.Rate this question:
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- 13.
The diffusion of water across a selectively permeable membrane is called
- A.
Osmotic pressure.
- B.
Osmosis.
- C.
Facilitated diffusion.
- D.
Active transport.
Correct Answer
B. Osmosis.Explanation
Osmosis is the diffusion of water.Rate this question:
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- 14.
Equilibrium is maintained through diffusion. Which of the following would represent equilibrium?
- A.
The concentration always remains greater inside a membrane.
- B.
The concentration eventually becomes balanced on both sides of a membrane.
- C.
The concentration always remains greater on the outside of a membrane.
- D.
The concentration becomes imbalanced on both sides of a membrane.
Correct Answer
B. The concentration eventually becomes balanced on both sides of a membrane.Explanation
Equilibrium is where the concentration is the same on both sides of the membrane.Rate this question:
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- 15.
Which of the following is NOT characteristic of facilitated diffusion?
- A.
It requires a protein channel.
- B.
It moves substances with (down) a concentration gradient.
- C.
It requires no energy input.
- D.
It is a type of active transport.
Correct Answer
D. It is a type of active transport.Explanation
Facilitated diffusion is a type of PASSIVE transport where materials diffusion through a protein channel.Rate this question:
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- 16.
The sodium-potassium pump is an example of
- A.
Contractile vacuoles
- B.
Osmosis
- C.
Active transport
- D.
Facilitated diffusion
Correct Answer
C. Active transportExplanation
The sodium-potassium pump is a protein pump that moves sodium and potassium ions against the concentration gradient. This requires energy in the form of ATP.Rate this question:
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- 17.
Sugar molecules are large and cannot go through the lipid bilayer. If there is a high concentration of sugar outside the cell, these molecules can ENTER cells through the process of
- A.
Exocytosis.
- B.
Facilitated diffusion.
- C.
Osmosis.
- D.
Ion pumps.
Correct Answer
B. Facilitated diffusion.Explanation
If the sugar is moving from high concentration to low concentration but cannot pass the lipid bilayer, it will move through a protein channel. This is called facilitated diffusion.Rate this question:
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- 18.
Food molecules and bacteria that are too large to be moved through the membrane can be transported INTO the cell by
- A.
Osmosis.
- B.
Endocytosis.
- C.
Lipid carriers.
- D.
Diffusion.
Correct Answer
B. Endocytosis.Explanation
Endocytosis transports large molecules and fluid into the cell, but it requires energy.Rate this question:
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- 19.
Placing a plant into a hypertonic environment will
- A.
Cause turgor pressure to increase because water is moving into the cell.
- B.
Cause the vacuole to swell.
- C.
Have no effect.
- D.
Cause turgor pressure to decrease because water is moving out of the cell.
Correct Answer
D. Cause turgor pressure to decrease because water is moving out of the cell.Explanation
A plant cell has a cell wall, which maintains the shape of the cell. Turgor pressure (the pressure inside the cell) decreases because the cell loses water in a hypertonic solution.Rate this question:
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- 20.
Red blood cells have a salt content of 0.9%. When a microbiologist places red blood cells in pure water, osmosis occurs. Where do the molecules move in this instance of osmosis?
- A.
Water molecules move out of the cells.
- B.
Water molecules move into the cells.
- C.
Salt ions move out of the cells.
- D.
Salt ions move into the cells.
Correct Answer
B. Water molecules move into the cells.Explanation
Water is always hypotonic to cells. The water will move into the cell causing it to swell.Rate this question:
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- 21.
A Paramecium lives in an environment that is hypotonic to its cytoplasm. How does the Paramecium maintain homeostasis under these conditions?
- A.
It expels (pumps out) excess water using contractile vacuoles.
- B.
It expels (pumps out) excess sodium using the sodium-potassium pump.
- C.
It absorbs additional water through osmosis.
- D.
It absorbs additional sodium through facilitated diffusion.
Correct Answer
A. It expels (pumps out) excess water using contractile vacuoles.Explanation
Because it is in a hypotonic solution, water moves into the cell (paramecium). To keep the cell from swelling, it pumps the water out using a contractile vacuole. This allows it to keep internal conditions the same (homeostasis).Rate this question:
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- 22.
Diffusion takes place
- A.
Only through a lipid bilayer membrane.
- B.
From an area of low concentration to an area of high concentration.
- C.
Only in liquids.
- D.
From an area of high concentration to an area of low concentration.
Correct Answer
D. From an area of high concentration to an area of low concentration.Explanation
Diffusion is a type of passive transport. That means molecules move from where they are crowded (high concentration) to where they are uncrowded (low concentration) without needing energy.Rate this question:
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- 23.
The dispersal of ink in a beaker of water is an example of
- A.
Diffusion.
- B.
Osmosis.
- C.
Active transport.
- D.
Endocytosis.
Correct Answer
A. Diffusion.Explanation
Diffusion is the spreading out of any type of molecule from high concentration to low concentration.Rate this question:
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- 24.
Passive transport is the movement of molecules from
- A.
An area of low concentration to an area of high concentration.
- B.
An area of high concentration to an area of low concentration.
- C.
An area of equilibrium to an area of high concentration.
- D.
An area of low concentration to an area of equilibrium.
Correct Answer
B. An area of high concentration to an area of low concentration.Explanation
Passive transport is where molecules spread out from high concentration to low concentration. Diffusion, Osmosis, and Facilitated Diffusion are all types of Passive Transport.Rate this question:
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- 25.
The process by which organisms keep their internal conditions fairly constant is called
- A.
Homeostasis.
- B.
Osmosis.
- C.
Metabolism.
- D.
Exocytosis.
Correct Answer
A. Homeostasis.Explanation
Homeostasis is maintaining stable internal conditions.Rate this question:
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- 26.
Active transport is the movement of molecules from
- A.
An area of low concentration to an area of high concentration.
- B.
An area of high concentration to an area of low concentration.
- C.
An area of high concentration to an area of equilibrium.
- D.
An area of low concentration to an area of equilibrium
Correct Answer
A. An area of low concentration to an area of high concentration.Explanation
Active Transport is the opposite of Passive Transport. Active Transport forces molecules to move against the gradient. This means they are moving from low concentration (uncrowded) to high concentration (crowded). This requires energy.Rate this question:
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- 27.
Pure water is always hypotonic to cells. An animal cell that is surrounded by pure water will burst because the osmotic pressure causes
- A.
Water to move into the cell.
- B.
Water to move out of the cell.
- C.
Solutes to move into the cell.
- D.
Solutes to move out of the cell.
Correct Answer
A. Water to move into the cell.Explanation
Water moves from where there is the most water (high) to where there is the least water (low). This means that because the fresh water is hypotonic to the cell, water will move into the cell, causing it to burst.Rate this question:
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- 28.
Which of the following is NOT a part of the cell membrane?
- A.
Phospholipids
- B.
Proteins
- C.
Carbohydrate chains
- D.
Nucleic acids
Correct Answer
D. Nucleic acidsExplanation
Nucleic acids are contained within the nucleus of eukaryotes and the cytoplasm of prokaryotes. Nucleic acids are not found in the cell membrane.Rate this question:
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.png "Refer to the illustration above. The process shown is called")
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Mar 20, 2023Quiz Edited by
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Jan 22, 2014Quiz Created by
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