Do Now 101 Plant and animal cells are different. Which organelle belongs to a plant cell, animal cell or both (mitochondria, chloroplast, cell wall, cell membrane). What is the function of a: Chloroplast – Mitochondria –

2 Important Chemical Reactions Photosynthesis & Cellular Respiration

How do organisms obtain nutrients? There are 2 ways: Heterotrophs Unable to synthesize own food. Ingests food (nutrients) produced by, or available in, other organisms. Autotrophs Autotrophs make their own food. Also called producers Plants do not need to ingest food. Glucose (nutrient) synthesized during photosynthesis

Why do living things need nutrition? For energy to carry out What do you call the sum total of all the chemical reactions (life functions) in an organism? Life Functions Metabolism

What are some types of autotrophs? Mostly green plants and some single-celled organisms Trees, grass, bushes, photosynthetic bacteria, algae

Photosynthesis

How do autotrophs make food? Photosynthesis Photo I Synthesis Light I Creates Purpose of Photosynthesis: … Is to create or synthesize GLUCOSE for the plant. The plant then uses the glucose to make ENERGY. Some animals eat plants so they can steal the glucose made in order for them to make energy!

Put into words, this equation tells us…. In the presence of light, plants transform CO2 and H2O into Glucose (stored chemical food energy) and releases O2 as a product. http://www.teachersdomain.org/asset/tdc02_vid_photosynth/

Photosynthesis Equations Carbon dioxide + water + light glucose+ oxygen C02 + H2O + Light C6H12O6 + O2 Inorganic molecules Organic molecule + O2 Sun’s Energy Stored chemical energy (bonds) How many types of enzymes will help catalyze the photosynthesis reaction? Could Photosynthesis occur without sunlight?

Hmmm… What is the ultimate source of energy? If photosynthesis did not take place, would we have oxygen to breath?

Where does photosynthesis take place? In chloroplasts found inside the cells of leaves Does photosynthesis take place in leaf, stems or a tree trunk?

How is light energy captured and used? Plant cells that are green contain chloroplasts. Chloroplasts contain chlorophyll…. What is chlorophyll? Why are plants/leaves green? What colors are absorbed best? A pigment (type of protein) that reflects green light and absorbs other colors. This is how light energy is captured! Green light is reflected by chlorophyll. Blues / Violet & Red / Maroon

Does the color of light affect photosynthesis? Conclusion: The color of light affects the rate of photosynthesis! The Effect of the Color of Light on Plant Height Fri Sat Sun Mon Tues Wed Thurs Green - 4 mm 9 mm 17 mm 20 mm Blue 6 mm 43 mm 50 mm 67 mm 67 mm** Red 2 mm 59 mm 64 mm 84 mm 87 mm Yellow Clear 37 mm 49 mm 70 mm 75 mm No light filter 54 mm 66 mm http://www.glencoe.com/sites/common_assets/science/virtual_labs/LS12/LS12.html

What is going on here? The “thing” in the beaker is a green elodea plant. What are those little bubbles in the test tube? Explain Bubbles of oxygen produced by Photosynthesis

Hmmm… How can we measure the rate of photosynthesis? Measure the amount of product produced! How? Measure the amount of Oxygen produced (#of bubbles) Measure the amount of plant (size, weight) If photosynthesis did not happen, would the plant produce sugar? Therefore, would the plant grow in size?

What could speed-up or slow-down the rate of photosynthesis? 6C02 + 6H2O + Light C6H12O6 + 6O2 http://www.biologycorner.com/flash/waterweed.html

Conclusions: Color of light : Light intensity: Amount of CO2:

Predict what would happen if photosynthesis did not take place Predict what would happen if photosynthesis did not take place? (give two examples). How could you improve the rate of photosynthesis? (Give at least 2 ways) How could you slow down or even stop photosynthesis? (Give at least 2 ways)

As the depth of the ocean increases, the amount of light that penetrates to that depth decreases. At about 200 meters, little, if any, light is present. The graph below illustrates the population size of four different species at different water depths. Which species most likely performs photosynthesis? a.  b.  c.  d.  Why?

How do plants get materials needed for photosynthesis? Roots - Absorb water from the ground. Where does the water go once it is absorbed? To the Leaves ! Site of photosynthesis Where CO2 & Sunlight are absorbed (reactants) Where H2O and O2 leave the plant (waste products)

How does water get up to the leaves? Transpiration pull Water evaporates through tiny holes in leaves called stomata Water is drawn up from the roots and stems to replace the lost water. **Remember, water is cohesive… water molecules love to stick together. When one water molecule evaporates, all the water in the stem is pulled up! https://www.youtube.com/watch?v=At1BJJDcXhk

Parts of leaf Guard cells & stomata Cuticle Spongy & Palisade Mesophyll

Guard Cells & Stomata Stomata – tiny opening on bottom-side of leaf. Where water evaporates and where CO2 and O2 enter and leave the cell. (H2O leaves through stoma) Guard cells – two cells surrounding the stomata (opening). These special cells open and close the stomata.

How do to the guard cells open and close? When plant have lots of water, the cells become expanded and “bow-out.” This opens the stomata. When water is low, the cells deflate, and close. ***How do guard cells help maintain homeostasis?

Palisade and Spongy Mesophyll Palisade mesophyll Top of leaf Right beneath epidermis Absorbs most of the light Where most photosynthesis happens in the leaf Spongy mesophyll Beneath the palisade mesophyll (bottom of leaf) Loose tissue, with many air spaces Lots of CO2 and O2 found here Where gas exchange happens

Time out…

Answer Me  How does CO2 and O2 enter and leave the cell? How does water enter and leave the cell? How is sunlight captured in leaves? What process takes place in leaves? And what’s the purpose? How do guard cells help maintain homeostasis?

Parts of leaf Cuticle Guard cells & stomata Spongy & Palisade Mesophyll Label your leaf! Page 6 in packet.

Another Look

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Review

Do Now Do plant cells have mitochondria? Do plant cells use oxygen and glucose? Why? So… do plants give off some carbon dioxide? (CO2)

Do Now What is needed (reactants) for photosynthesis? What are the products of photosynthesis? Why does photosynthesis take place? Why is it important?

Do Now (5) Finish the formula: ______________ + ________ + light __________+ __________