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. What did you use as the selectively permeable membrane in your investigation of osmosis?
A. Visking tubing
Q. What is active transport?
A. Movement of molecules against a concentration gradient using energy
Q. Name two substances that enter a human muscle cell by diffusion.
A. Oxygen; glucose; water; amino acids; phosphate; iron
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)
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 is meant by osmoregulation?
A. Controlling the water/salt balance within an organism
Q. Where precisely does water enter a plant?
A. Root hairs
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
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