Wednesday, Oct. 29 - Cells - Plant Structure

Objective: To understand the structure of plantss and how plants make their own food through photosynthesis.

Plants are vascular (true land plants, seedless and seed plants) or nonvascular (no true roots, stems, etc. – moss)

Seed plants use seed to reproduce – gymnosperms produce seeds not in a fruit, form cones (think pine trees); angiosperms are flowing plants – daisies, fruit trees – seeds are enclosed in a fruit. The fruits are usually edible and the seeds are not usually digestible so animals usually spread them far from parents. More angiosperms.

Parts of a Plant

• Roots – absorb water and minerals; taproot, fibrous root
• Stems – support the leaves fruits, flowers, seeds; have xylem (tubeshaped cells that move water and minerals) and phloem (tube shaped tissue that transport molecules from leaves through plant); herbaceous, woody
• Leaves – main function is to capture energy and exchange gasses (photosynthesis). Outer layer is epidermis.
• Flowers – pollination. (see diagram page 114)
• Seeds

Photosynthesis

Plants change light energy into chemical energy – they make their own food.

Photosynthesis takes place mostly in the leaves, but can take place in green stems. These have cells called chloroplasts, which is where photosynthesis happens. Chloroplasts have membranes called thylakoids, which contain chlorophyll, which absorbs sunlight.

Plants need carbon dioxide and water for photosynthesis. They breathe in carbon dioxide and breathe out oxygen.