Plant Biology Quiz

Kingdom Plantae

• Bryophytes (mosses) have short vertical stems, leaf-like structures (one cell thick), and a variety of ecosystems; they are the second most diverse plant group, double the amount of mammals.

• Pteridophytes (ferns) thrive in warm, moist environments (cooler and drier habitats); they have roots, stems, and prominent leaves and leaves emerge curled (fiddleheads).

• Gymnosperms (conifers) have seeds exposed on cones, scales; they are the most dominant woody vegetation in Canada (evergreen - year-round photosynthesis); examples include pines, firs, and cedars.

• Angiosperms (flowering plants) use flowers to reproduce, seeds in fruit; they are very diverse; examples include roses, trilliums, grasses, roadside weeds, etc; they make up 90% of all plants.

Organization of Plants

• Organism: A complete living thing.

• Organ System: A group of organs working together.

   - **Root System:** Anchors the plant, absorbs water and minerals, stores food, and transports and produces hormones.
  - **Shoot System:** Includes leaves (photosynthesis), stems (support), flowers and fruits (reproduction), storage, transport, and hormone production.
  

• Organs: Structures within an organ system. - Roots: absorb water and minerals, anchor the plant, and store food. - Stems: Support and transport water and nutrients throughout the plant. - Leaves: Responsible for photosynthesis.

• Tissues: Groups of similar cells that work together.

• Cells: Basic units of life.

Meristematic Tissue

• Apical Meristem: Tissue that grows at root and shoot tips for primary growth.

• Lateral Meristem: Increases diameter of roots and stems through secondary growth e.g. vascular cambium.

Ground Tissue

• Parenchyma: Living, flexible cells; performs varied functions such as storage, photosynthesis, and gas exchange.

• Collenchyma: Living cells with unevenly thickened primary walls; provides flexible support to plant tissues.

• Sclerenchyma: Primarily involved in support; dead at maturity with thick secondary cell walls reinforced with lignin.

Vascular Tissue

• Xylem: Transports water and dissolved minerals from roots to leaves.

• Phloem: Transports sugars from leaves to other parts of the plant.

Plant Structure & Function (Roots)

• Functions: Take in water and dissolved minerals, transport them, anchor the plant, support, and store carbohydrates produced by photosynthesis.

• Water Absorption: Roots extend towards water sources like shallow branching roots & deeper roots expanding their reach.

• Root Types: Taproots (e.g., carrots), Fibrous Roots (e.g., onions), Modified Roots (e.g., tubers)

Plant Structure & Function (Stems)

• Functions: Support, storage and the transport link between leaves and roots.

• Herbaceous stems: Annual plants, lack woody tissue/bark, and have chlorophyll in the stems and leaves; usually do not live more than a year. Eg. bean.

• Woody stems: Perennial plants/trees, have woody tissue/bark and chlorophyll in leaves only; usually live more than a year. Eg. maple tree.

• Wood: Vascular tissue produced each year, as woody plants grow taller increasing the diameter of the stem.

Plant Structure & Function (Leaves)

• Functions: Photosynthesis, gas exchange, and protection.

Vascular bundles in stems

• Monocots: Scattered and surrounded by ground tissue.

• Dicots: Arranged in a ring.

Plant Hormones

• Auxins: Stimulate cell division and elongation, respond to light and gravity (tropism).

• Cytokinins: Stimulate cell division, promote cell enlargement.

• Gibberellins: Stimulate cell elongation and seed germination; promote seed ripening.

• Ethylene: Promotes ripening of fruit.

• Abscisic Acid: Introduces and ensures dormancy of seeds, inhibits shoot growth, and closes stomata.

Tropisms

• Phototropism: Growth response to light.

• Gravitropism: Growth response to gravity.

• Thigmotropism: Growth response to touch.