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PLANT PROCESSES. ENERGY PROCESSING IN PLANTS. Materials For Plant Processes. To survive, plants need food, water, and oxygen. Roots absorb water which travels inside xylem cells to all parts of a plant. Most plants make their own food (Glucose) w hich flows to all plant cells.
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Materials For Plant Processes • To survive, plants need food, water, and oxygen. • Roots absorb water which travels inside xylem cells to all parts of a plant. • Most plants make their own food (Glucose) which flows to all plant cells. • Plants require oxygen and carbon dioxide to make food.
PHOTOSYNTHESIS • Photosynthesis is a series of chemical reactions that converts light energy into chemical energy (Glucose)
Leaves are the major- food producing organs of plants. • The cells that make up the top layer of a leaf are flat, irregularly shaped cells called epidermal cells. • On the bottom of the epidermal layer of leaves are small openings called stomata. PHOTOSYNTHESIS
Mesophyll cells contain chloroplasts, the organelle where photosynthesis occurs. • Chemicals that can absorb and reflect light are called pigments. • The pigment chlorophyll reflects green light, absorbs other colors of light, and uses this energy for photosynthesis. PHOTOSYNTHESIS
During photosynthesis, water molecules are split apart releasing oxygen into the atmosphere. • Sugars are made in the second step of photosynthesis. • Photosynthesis is important because it produces most of the oxygen in the atmosphere PHOTOSYNTHESIS
CELLULAR RESPIRATION Cellular Respiration – converts the energy in food molecules into a usable form of energy called ATP
CELLULAR RESPIRATION • Occurs in the mitochondria of Eukaryotic cells and requires oxygen • Glucose broken down • Large amounts of usable energy called ATP are produced • Water and Carbon Dioxide is given off
Cellular respiration is important to plants because without it they could not grow, reproduce, or repair tissue • Life on Earth depends on a balance of photosynthesis and cellular respiration
Stimuli are any changes in the environment that cause an organism to react. • Plants respond to different environmental stimuli such as: • light • touch • gravity • A tropism is a response that results in plant growth toward or away from a stimulus.
Phototropism • Tendency of plants to grow toward a source of light • Leaves and stems tend to grow in the direction of light • Roots grow away from light
Thigmotropism • A response of a plant to touch
Gravitropism • Response of a plant to the force of gravity • Stems grow away from gravity • Roots grow toward gravity
Photoperiodism • Response to the number of hours of darkness in its environment. • Long-day plants- flower when exposed to less than 10-12 hours of darkness • Short-day plants- require 12 or more hours of darkness for flowering to begin • Day-neutral plants- flower when they reach maturity and the environmental conditions are right.
Hormone • Substances that act as chemical messengers. • They are produced in one part of an organism and affects another part of the same organism
Auxin • Hormone that caused increased plant growth.
Ethylene • Plant hormone that stimulates fruits to ripen
Gibberellin • Hormone that increases the rate of cell division and cell elongation in stems and leaves and fruit.
Cytokinin • Plant hormone that increases the rate of cell division in some plants and slow the aging process of flowers and fruits • Causes dormant seeds to sprout