Photosynthesis Photosynthesis Song

Photosynthesis Notes The Sun - Ultimate source of all energy on Earth! Autotrophs – plants and some other organisms (algae & bacteria) that are able to use light energy from the sun to produce food Heterotrophs – cannot produce their own food, obtain energy from the foods they consume (eat) (ex. Humans and other animals)

Autotrophs: Heterotrophs:

Photosynthesis is the process by which autotrophs use the energy of sunlight to convert water and carbon dioxide into oxygen and high-energy carbohydrates – sugars and starches. Chloroplasts – site of photosynthesis within the cell Chlorophyll – a green pigment found in the chloroplast absorbs light energy

Photosynthesis Equation 6CO2 + 6H2O light C6H12O6 + 6O2 E carbon dioxide + water glucose + oxygen Opposite of Respiration C6H12O6 + 6O2 6CO2 + 6H2O + ATP!!

Light Dependent Reactions Require direct involvement of light and light absorbing pigments. Use the energy from sunlight to produce ATP. Take place in the thylakoids. Water is required and oxygen is released as a by-product.

Light Independent Reactions ATP is used to produce high energy sugars from carbon dioxide. No light is required. Take place in the stroma.

What factors can affect the Rate of Photosynthesis?? Amount of light (more light, more photos.) Availability of water Temperature (enzymes that work best between 0 – 35 degrees C) pH of soil/water (can affect enzymes)

Uses for Glucose Produced Energy source for cellular respiration Can be converted into more complex starches (like cellulose) by plants

Uses for Oxygen being Produced Main source of oxygen required by most living things for cellular respiration Plants can transfer some of the oxygen produced to their own mitochondria!

Cuticle Upper epidermis Palisades Mesophyll Mesophyll Spongy Mesophyll Chloroplasts Xylem (water) Lower Epidermis Phloem (glucose) Vein (xylem & phloem Guard Cells Stomate (Stoma)

Protective layer, contains guard cells and stomates Protective layer, transparent covering Tightly packed cells, MOST photosynthesis happens here Waxy covering on top of leaf – protects from rain / weather Opening - underside of leaves, allows CO2/H2O in & O2 out!! Control (REGULATE) the opening and closing of stomates TRANSPORTS water and glucose through plant Allow gases to circulate!! (Oxygen and carbon dioxide) Makes the spongy layer “spongy” Part of the vein that carries water up Part of the vein that carries glucose down Sites of photosynthesis (use the pigment chlorophyll) Inner / middle of leaf – contains the spongy and palisades

Practice Questions Which process is directly used by autotrophs to store energy in glucose? (1) diffusion   (2) respiration  (3) photosynthesis (4) active transport

Practice Questions What does the process of photosynthesis produce? 1) starch, which is metabolized into less complex molecules by dehydration synthesis 2) protein, which is metabolized into less complex molecules by dehydration synthesis 3) glycerol, which is metabolized into more complex carbohydrates by dehydration synthesis 4) glucose, which is metabolized into more complex carbohydrates by dehydration synthesis

Practice Questions Which process provides most of the oxygen found in Earth's atmosphere? 1) photosynthesis 2) aerobic respiration 3) dehydration synthesis 4) fermentation

Photosynthesis Respiration Main Job: Main Job: BOTH Who does it?: Who does it?: Reactants (what it needs): Reactants (what it needs): Products (what it makes): Products (what it makes): Where? Where?