Water Potential, Diffusion And Active Transport
A quiz on water potential, diffusion, active transport and other cellular transport.
HUMAN BIOLOGY AS LEVEL
Questions and Answers
- 1.
Diffusion is the ____ _________ of a substance from a region where it is in ______ concentration to a region where it is in ______ concentration.
Explanation
Diffusion is the process of a substance moving from an area of higher concentration to an area of lower concentration. This movement occurs due to the random motion of molecules, which causes them to spread out and distribute themselves evenly. The net movement refers to the overall direction of this diffusion process, which is always from an area of higher concentration to an area of lower concentration.Rate this question:
- 2.
Diffusion is said to be a _______ process.
Explanation
Diffusion is said to be a passive process because it does not require the input of energy. In diffusion, particles move from an area of higher concentration to an area of lower concentration, driven by the random motion of the particles themselves. This movement occurs naturally and spontaneously, without the need for any external force or energy expenditure. Therefore, diffusion is considered a passive process.Rate this question:
- 3.
What can not diffuse through the phospholipid bilayer?
- A.
Small, lipid-soluble molecules
- B.
Molecules that are soluble in water
- C.
Charged particles such as ions
Correct Answer(s)
B. Molecules that are soluble in water
C. Charged particles such as ionsExplanation
Molecules that are soluble in water and charged particles such as ions cannot diffuse through the phospholipid bilayer. The phospholipid bilayer is composed of hydrophobic tails that repel water, making it impermeable to water-soluble molecules. Additionally, the bilayer is also selectively permeable to ions, as their charged nature prevents them from easily passing through the hydrophobic interior of the membrane. Therefore, only small, lipid-soluble molecules can freely diffuse through the phospholipid bilayer.Rate this question:
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- 4.
Facilitated diffusion is the diffusion of molecules through the plasma membrane with the help of ________. Some of these are protein _______ that are permanently open. They are lined with _____philic amino acids and water. Molecules can also diffuse through the membrane by binding to ______ proteins.
Correct Answer(s)
proteins channels hydro carrierExplanation
Facilitated diffusion refers to the passive movement of molecules across the plasma membrane with the assistance of specific proteins. These proteins, known as channels, act as passageways that are always open, allowing molecules to pass through. The channels are lined with hydrophilic amino acids, which attract and interact with water molecules. Additionally, some molecules can diffuse through the membrane by binding to carrier proteins, which undergo a conformational change to transport the molecules across the membrane.Rate this question:
- 5.
What kind of process is facilitated diffusion?
- A.
Active
- B.
Passive
Correct Answer
B. PassiveExplanation
Facilitated diffusion is a type of passive process. Passive processes do not require energy expenditure and rely on the concentration gradient to move molecules across the cell membrane. In facilitated diffusion, specific transport proteins help facilitate the movement of molecules across the membrane, but the process itself does not require the cell to expend energy. Therefore, the correct answer is passive.Rate this question:
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- 6.
Osmosis is the movement of ______ molecules from a region of _____ water potential to a region of _____ water potential.
Correct Answer
water high lowExplanation
Osmosis is the movement of water molecules from a region of high water potential to a region of low water potential. This means that water molecules will naturally flow from an area where there is a higher concentration of water molecules (high water potential) to an area where there is a lower concentration of water molecules (low water potential).Rate this question:
- 7.
Pure water has the highest possible water potential of ___ .
Correct Answer
0
zeroExplanation
Pure water has the highest possible water potential because it is in its purest form without any solutes or contaminants. Water potential is a measure of the tendency of water to move from one area to another, and pure water has the maximum potential for movement. Therefore, the water potential of pure water is 0 or zero.Rate this question:
- 8.
Adding solutes to water ______ the water potential, for example it makes the water potential more ______.
- A.
Increases, positive
- B.
Increases, negative
- C.
Decreases, negative
- D.
Decreases, positive
Correct Answer
C. Decreases, negativeExplanation
Adding solutes to water decreases the water potential. This is because solutes lower the concentration of water molecules in the solution, reducing the tendency of water to move by osmosis. The water potential becomes more negative as the solute concentration increases.Rate this question:
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- 9.
Osmosis occurs until the water potential is the same on both sides of the membrane. At this point, ___________ has been reached.
Correct Answer
equilibriumExplanation
Osmosis is the movement of water molecules from an area of higher water potential to an area of lower water potential through a selectively permeable membrane. When the water potential is the same on both sides of the membrane, it means that the concentration of solutes is equal on both sides, resulting in no net movement of water molecules. This state is called equilibrium, where there is a balance in the movement of water molecules, and osmosis stops.Rate this question:
- 10.
A solution with the same water potential as a cell is said to be _______ with the cell.
Correct Answer
isotonicExplanation
A solution with the same water potential as a cell is said to be isotonic with the cell. This means that the concentration of solutes in the solution is equal to the concentration of solutes inside the cell. As a result, there is no net movement of water across the cell membrane, and the cell maintains its shape and volume.Rate this question:
- 11.
A solution with a lower water potential than the cell is said to be __________.
Correct Answer
hypertonicExplanation
A solution with a lower water potential than the cell is said to be hypertonic. This means that the solution has a higher solute concentration than the cell. As a result, water will move out of the cell and into the solution through osmosis, causing the cell to shrink or undergo plasmolysis.Rate this question:
- 12.
A solution with a higher water potential than the cell is said to be _________.
Correct Answer
hypotonicExplanation
A solution with a higher water potential than the cell is said to be hypotonic. In a hypotonic solution, there is a lower concentration of solutes outside the cell compared to inside the cell. This causes water to move into the cell through osmosis, resulting in the cell swelling or potentially bursting if the solution is extremely hypotonic.Rate this question:
- 13.
Glucose and other solutes will dissolve in blood plasma and ______ the water potential but it is mainly the concentration of electrolytes in plasma and in cells that is responsible for maintaining a water potential ________. Electrolytes are ions with a positive or negative _______. Positively charged ions are called _______ and those with a negative charge are called _______.
Correct Answer
lower balance charge cations anionsExplanation
Glucose and other solutes will dissolve in blood plasma and contribute to the lowering of water potential, but it is mainly the concentration of electrolytes in plasma and cells that is responsible for maintaining a balanced water potential. Electrolytes are ions with a positive or negative charge. Positively charged ions are called cations and those with a negative charge are called anions.Rate this question:
- 14.
Diffusion, osmosis and facilitated diffusion go ______ the concentration gradient.
- A.
Against
- B.
Down
Correct Answer
B. DownExplanation
Diffusion, osmosis, and facilitated diffusion all occur down the concentration gradient. This means that they move from an area of higher concentration to an area of lower concentration. In diffusion, molecules move freely from an area of high concentration to low concentration. Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. Facilitated diffusion involves the use of proteins to help molecules move down their concentration gradient. In all these processes, the movement is always down the concentration gradient.Rate this question:
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- 15.
Active transport is the movement of a substance across a cell membrane ______ its concentration gradient, using energy from ___.
Correct Answer
against ATPExplanation
Active transport is a process in which a substance is moved across a cell membrane against its concentration gradient, meaning from an area of lower concentration to an area of higher concentration. This process requires the input of energy, which is provided by ATP (adenosine triphosphate). ATP is a molecule that stores and releases energy for cellular processes, including active transport. Therefore, the correct answer is "against ATP".Rate this question:
- 16.
Exocytosis is...?
- A.
Is when after the the bacterium has been digested, the waste products are released back out of the cell
- B.
Is when the bacterium is engulfed into the cell
Correct Answer
A. Is when after the the bacterium has been digested, the waste products are released back out of the cell -
- 17.
Endocytosis is...?
- A.
Is when after the the bacterium has been digested, the waste products are released back out of the cell
- B.
Is when the bacterium is engulfed into the cell
Correct Answer
B. Is when the bacterium is engulfed into the cellExplanation
Endocytosis is a cellular process in which the cell engulfs external material, such as bacteria, by forming a vesicle around it. This allows the cell to internalize and transport the material into its cytoplasm. The correct answer states that endocytosis is when the bacterium is engulfed into the cell, which accurately describes the process.Rate this question:
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Current Version
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Mar 19, 2023Quiz Edited by
ProProfs Editorial Team -
Oct 02, 2011Quiz Created by
Nuzzzzie
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