Absorption Flashcards
What is the need for water and minerals in plants?
— Photosynthesis
— Transpiration
— Transportation: of mineral salts etc that get dissolved in water from roots to upper parts or other substances from leaves to other parts.
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What is the main function of plant roots?
To absorb water and mineral nutrients from the soil and conduct them into the stem for supply to other plant parts.
List four purposes of water inside the plant body.
Photosynthesis, transpiration, transportation, and mechanical stiffness.
How is water used in photosynthesis?
Water is used as a raw material in the synthesis of glucose in the green leaves.
What happens to water during transpiration?
A large quantity of water evaporates as water vapor, serving purposes such as cooling in hot weather and producing a suction force.
Define transportation in plants.
Transportation refers to the movement of substances in water solution, such as mineral salts from roots upward into the shoot or sugars from leaves to other parts.
What role does water play in providing mechanical stiffness in plants?
Water provides turgidity, which is necessary for the stiffness of plant tissues.
Where are mineral nutrients required by plants absorbed from?
Mineral nutrients are absorbed from the soil by the roots.
How are mineral nutrients absorbed by plants?
Some nutrients are absorbed as salts (nitrates, phosphates, sulphates, etc.), while others are absorbed simply as ions (potassium, calcium, magnesium, chlorine, etc.).
What is imbibition?
Imbibition is the absorption of water by living or dead plant cells due to surface attraction.
What are hydrophilic substances?
Substances made up of cellulose or proteins, such as dry seeds or wooden doors, which swell up when in contact with water.
Define diffusion.
Diffusion is the free movement of molecules from their region of higher concentration to their region of lower concentration when they are in direct contact.
What is osmosis?
Osmosis is the movement of water molecules from their region of higher concentration to their region of lower concentration through a semi-permeable membrane.
What is endosmosis?
Endosmosis is the inward diffusion of water through a semi-permeable membrane when the surrounding solution is less concentrated.
What is the significance of diffusion?
- transpiration
- exchange of respiratory gases
- abs of water by roots
What is exosmosis?
Exosmosis is the outward diffusion of water through a semi-permeable membrane when the surrounding solution is more concentrated.
What is the selective or differentially permeable membrane in an experiment demonstrating osmosis?
cellophane paper, that allows water molecules to pass through but not larger solute molecules like sugar.
OR parchment paper, visking bag, animal bladder, egg membrane, dialysis bag
What happens if a rubber sheet is used as a barrier in osmosis?
The rubber sheet is impermeable and does not allow water molecules to cross over to the other side.
What happens if a muslin cloth is used as a barrier in osmosis?
The muslin cloth has larger pores and allows even the sugar molecules to pass through, causing the entire sugar solution to flow down to a common level.
What are three main conclusions from osmosis experiments?
Water from the beaker passes through the cellophane paper to the thistle funnel, sugar from the thistle funnel does not pass into the beaker, and the cellophane paper acts as a selective or differentially permeable membrane.
What is osmotic pressure?
It is the minimum pressure required to nullify osmosis
