Plant Structure Flashcards
All 10 cards in this deck
What is the main function of a root hair cell?
To absorb water and mineral ions from the soil.
How does the long, narrow shape of a root hair cell help it?
It gives a large surface area for faster absorption of water and mineral ions.
Why do root hair cells contain many mitochondria?
To release energy for active transport of mineral ions into the cell.
By which process does water enter a root hair cell, and why?
Osmosis — the soil water is a more dilute solution than the cell's cytoplasm, so water moves in through the partially permeable membrane.
True or false? Mineral ions enter root hair cells by osmosis.
False. Mineral ions enter by active transport, against the concentration gradient, using energy; osmosis only moves water.
Name two substances transported by xylem and state the direction of movement.
Water and mineral ions, carried upwards from the roots to the leaves.
Give two structural features of xylem vessels.
Thick (lignified) walls and continuous hollow tubes with no end walls.
Why are xylem vessel walls lignified?
Lignin strengthens the walls, supporting the plant and stopping the vessel collapsing.
Describe the structure of phloem tissue.
Living cells joined end to end with sieve plates that have pores, plus companion cells containing many mitochondria.
True or false? Phloem transports sucrose without using any energy.
False. Phloem cells are living and use energy (from companion cell mitochondria) to transport sucrose.