Plants Structures & Functions

Characteristics of Plants Eukaryotic Multicellular Autotrophs Cell walls made of cellulose Remember biomolecules?

Importance of plants Earth’s major producers Provide food and shelter for many organisms Supply oxygen needed for cellular respiration

Leaves Broad, flat organ that traps light energy Contain 1000s of chloroplasts for photosynthesis Why are leaves considered organs? (hint: think levels of organization)

Cross-section of a leaf: (Plural: Stomata) (protection) (allows gas xchg) (photosynthesis)

What type of biomolecule makes up the cuticle? Protective waxy layer on leaves Prevent evaporation & tissues from drying out What type of biomolecule makes up the cuticle?

Stomata Openings on the surface of the leaf Regulated by guard cells - allow for gas exchange during photosynthesis (Take in CO2, release O2 Can close to prevent water loss – transpiration

Stem Provides support for upright growth Contains tissues for transporting food, water, and nutrients from one part of the plant to another

Xylem carries water from the roots to the leaves Phloem ‘flows’ sugars/food from leaves down to roots

Vascular Bundles in a Stem Xylem Phloem Would stems be considered organs? Why or why not?

Summary Vascular Tissue Direction Substance Xylem Leaves  Roots Water Phloem  Sugar

Roots Anchors plant in ground Absorbs water & minerals from soil Transports nutrients to stem Would roots be considered organs? Why or why not?

Seeds Contain an embryo, food supply and is surrounded by a protective covering. Are enclosed in fruit or cones (endosperm)