Cell Processes and Energy Chapter 11

Photosynthesis ALL living things directly or indirectly receive energy from the energy of sunlight captured during PHOTOSYNTHESIS! During photosynthesis, plants use energy from the sun to convert carbon dioxide and water into oxygen and sugars

Photosynthesis: Stage 1 Capturing the Sun’s Energy Mostly happens in leaves Chloroplasts (organelles in plant cell) contain pigments that absorb light Chlorophyll, a pigment, captures light energy and uses it to power the second stage

Photosynthesis: Stage 2 Using Energy to Make Food Plants need water (absorbed by roots) and carbon dioxide, a gas in the air that enters the plant through stomata (small openings on underside of the leaves) Water and Carbon dioxide move into chloroplasts Water and Carbon Dioxide go through a chemical reaction powered by sunlight energy.

Products of Photosynthesis: Sugar – C6H1206 Type of carbohydrate(energy) Used by cell to carry out cell functions Oxygen -02 Exits through stomata

Photosynthesis VS Cellular Respiration 6 CO2 + 6 H20  C6H1206 + 6 02 Cellular Respiration: C6H1206 + 6 02  6 CO2 + 6 H20 **THEY MIRROR EACH OTHER! TOGETHER, THEY KEEP O2 AND CO2 LEVELS ON EARTH FAIRLY CONSTANT

Cellular Respiration Respiration – how cells get energy from glucose Cells break down food (sugar) to release energy Carried out continuously! A “savings account” of energy 2 stages

Cellular Respiration Stage 1: Stage 2: In cytoplasm Glucose are broken down into smaller molecules Stage 2: In mitochondria (the “powerhouse”) Molecules broken down even smaller

Fermentation Provides energy to cell without using oxygen Alcoholic Fermentation: Ex. yeast breaks down sugar and produces energy, CO2 and alcohol. CO2 produces air pockets, causing dough to rise Lactic Acid Fermentation: When muscle cells use up oxygen faster than your body can replace it