2.2.6 Movement through Membranes FMQuiz Homework Solution
Q. Water enters the outermost cells of the root by
osmosis. What does this tell you about the cell sap
of these outermost cells?
A. Lower water concentration or higher solute
concentration
Q. Osmosis has been described as a special case of
diffusion. Explain why.
A. Movement of water along a concentration
gradient through a selectively permeable
membrane
Q. What is meant by a selectively permeable
membrane?
A. Allowing some substances to pass through
Q. Give locations in a cell at which there is a
selectively permeable membrane.
A. Chloroplast, mitochondrion, nucleus, vacuole
Q. What is diffusion?
A. Movement of molecules from area of high
concentration to area of lower concentration
Q. Why is diffusion alternatively known as passive
transport?
A. No energy (ATP) required
Q. Explain the biological basis for the use of high
sugar or high salt concentrations in the
preservation of food.
A. Bacteria lose water by osmosis; this leads to
inactivity or death
Q. Explain the term turgor.
A. Pressure of cell contents on cell wall
Q. Give an example of osmosis in plants.
A. Water movement between cells or from soil to
root
Q. Name a substance found in a plant cell vacuole.
A. Water or sugar or sap or salt(s) or protein
Q. Give a feature of a plant cell that allows it to
remain turgid for long periods.
A. Vacuole or cell wall or cell sap
Q. True or False. Plant cell walls are fully
permeable.
A. TRUE
Q. Water for photosynthesis enters the roots of
plants by what process?
A. Osmosis
Q. Suggest a way in which turgor is of value to
plants.
A. Support
Q. Name the terms used in biology to describe the
movement of substances through cell membranes.
A. Diffusion; Osmosis; Active transport
Q. What process is responsible for the uptake of
minerals in a plant?
A. Active transport
Q. What did you use as the selectively permeable
membrane in your investigation of osmosis?
A. Visking tubing
Q. What is meant by osmoregulation?
A. Controlling the water/salt balance within an
organism
Q. What is active transport?
A. Movement of molecules against a concentration
gradient using energy
Q. Where precisely does water enter a plant?
A. Root hairs
Q. Name two substances that enter a human
muscle cell by diffusion.
A. Oxygen; glucose; water; amino acids; phosphate;
iron
Q. The drooping of the leaves of a plant resulting
from loss of turgidity due to lack of water is known
as …
A. Wilting
Q. In which tissue does water ascend through the
plant?
A. Xylem
Q. Suggest an advantage to the cell of having a
selectively permeable membrane.
A. Substances can be kept in (or out) or substances
can be let in (or out)
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