OpenRevise

Biology · Edexcel Paper 2

Plant Structures and Transport

How water and mineral ions enter a plant through the root hair cells and move up the xylem by transpiration, how the phloem carries sucrose by translocation, how a leaf is adapted for photosynthesis and gas exchange, and how the environment changes the rate of water uptake. Matches Edexcel Topic 6, points 6.7 to 6.13. Every lesson is for both Combined Science and separate Biology, except the structure of a leaf (6.11B), which is Biology only.

  • 4 lessons
  • All boards
Flashcards Exam questions Print as a revision pack

Lessons

Ticks are remembered on this device only.

Key terms in this chapter

All 32, gathered from every lesson.

Root hair cell
A cell on the surface of a root with a long thin extension that takes up water and mineral ions.
Xylem
Tissue made of dead hollow cells strengthened with lignin that carries water and mineral ions from the roots to the leaves.
Lignin
A strong material that strengthens the walls of the xylem.
Transpiration
The loss of water vapour from the leaves of a plant, mainly through the stomata.
Transpiration stream
The movement of water up the xylem from the roots to the leaves.
Stoma
A tiny pore in the leaf surface, controlled by two guard cells. The plural is stomata.
Humidity
The amount of water vapour in the air.
Mineral ions
Substances such as nitrate and magnesium that plants take up from the soil for healthy growth.
Phloem
Living tissue made of tubes of elongated cells that carries dissolved sugars around a plant.
Translocation
The movement of dissolved sugars through the phloem from the leaves to the rest of the plant.
Sucrose
The sugar in which the glucose made in photosynthesis is transported.
Companion cell
A cell next to a phloem cell that supplies it with energy.
Storage organ
A part of a plant, such as a root or tuber, where food is stored.
Cell sap
The solution of sugars and other substances inside the cells.
Source
A part of the plant where sugars are made, such as a leaf.
Sink
A part of the plant where sugars are used or stored.
Epidermis
The thin outer layer of cells that covers a leaf.
Waxy cuticle
A waxy layer on the upper surface of a leaf that reduces water loss.
Palisade mesophyll
A layer of tall, tightly packed cells full of chloroplasts, where most photosynthesis takes place.
Spongy mesophyll
A layer of loosely packed cells with air spaces, which allow gases to move through the leaf.
Stoma
A tiny pore in the lower epidermis of a leaf that allows gases and water vapour to pass. The plural is stomata.
Guard cell
One of a pair of cells that open and close a stoma.
Meristem
Tissue at the tips of shoots and roots whose cells can divide and differentiate into any type of plant cell.
Turgid
Firm and swollen with water.
Potometer
Apparatus that measures the rate at which a plant shoot takes up water.
Capillary tube
A very thin tube in which the bubble moves in a potometer.
Independent variable
The variable that is changed in an investigation.
Dependent variable
The variable that is measured in an investigation.
Control variable
A variable that is kept the same so the test is fair.
Mean
An average found by adding up the values and dividing by how many there are.
Stomatal density
The number of stomata in a given area of leaf.
Reliable
Giving similar results when the investigation is repeated.