Praxis Middle School Science-Plants Flashcards
What are nonvascular plants.
They represent a grade of evolution characterized by several primitive features:
- lack of roots and conducting tissues.
- reliance on random absorption of water or high humidity.
- lack of typical leaves.
Vascular Plants
characterized by lignin, which gives strength for the growing upright, tracheid cells for water transport and sieve cells for nutrient transport, and underground root systems.
What are the two kinds of vascular plants?
Seeded and non-seeded
-they differ by method of reproduction.
How are vascular seed plants divided?
- gymnosperms: the first plants to evolve with the use of seeds for reproduction.
- angiosperms: the flowering plants who produce true seeds for reproduction. They have more advanced vascular tissue and larger leaves for increased photosynthesis.
How are angiosperms divided?
- Monocots: have one cotelydon (seed leaf) with parallel veins on their leaves and flower petals in multiple of three.
- dicots-have two coteyldons with branching leaf veins and flower petals in multiple of fours or fives.
What do roots do for plants?
They absorb water and minerals and exchange gases in the soil.
What do roots contain?
- xylem sap: transports minerals and water upwards
- phloem sap: the sugar produced in photosynthesis travels down the phloem sap the roots and other nonphotosynthetic parts of the plant.
What function do stems have?
Stems are the major support structure of plants.
What three types of tissue do stems contain?
- Dermal tissue: covers the outside surface of the stem to prevent excessive water loss and control gas exchange.
- Ground tissue: consists mainly of parenchyma cells and surrounds the vascular tissue, providing support and protection.
- Vascular tissue: xylem and phloem, providing long distance transport of nutrients and water.
What are function of leaves?
Leaves enable plants to capture light and CO2 for photosynthesis.
How do plants exchange gasses?
They exchange gases through stomata: small openings on the underside of leaves.
What are plant hormones?
They are chemicals secreted internally by plants. They regulate growth and development.
What is hormone signalling?
Signalling involves attachment of hormone molecules to protein receptors, transmission of the signal along a transduction pathway, and the activation of particular genes.
Name the 5 major classes of plant growth regulators.
- auxins
- abscisic acid
- gibberellins
- ethylene
- cytokinins
What is phototropism?
It is the tendency of plants to bend towards the light.
