REACTIONS of PHOTOSYNTHESIS

Research into PHOTOSYNTHESIS began centuries ago with this simple question: When a tiny seed grows into a huge plant, where does all the “new plant” come from?

EXPERIMENTS TO FIND OUT Then he planted the seedling in the pot and watered it regularly. At the end of 5 years the _____________ __________about 75 kg, but the mass of the _________ was almost ________________. He decided the “increase in plant” had to come from the ________… that was the only thing he had added! In a Belgian physician ___________________ determined the mass of a pot of dry soil and a small seedling. Jan van Helmont seedling had gained soil unchanged WATER

EXPERIMENTS TO FIND OUT Plants use _______ and ______ dioxide to make ___________________ Van Helmont didn’t realize the major contribution to the mass of his tree was something he couldn’t see… __________________ from the air. carbon dioxide watercarbon Carbohydrates

EXPERIMENTS TO FIND OUT An English minister, _________________________, discovered that a flame burning in a closed jar would die out. If he placed a __________ in the jar and allowed a few days to pass, the candle could be lit again. The plant produced something “required for burning” that the candle used up We now know it was …____________ OXYGEN Joseph Priestley live plant

EXPERIMENTS TO FIND OUT Dutch scientist ________________________ showed Priestley’s plant experiment only worked if the plant was exposed to _________________ ! Jan Ingenhousz light

THE BIG PICTURE These experiments led to work by later scientists who finally discovered that in the presence of light, plants transform CO 2 and water into carbohydrates and release oxygen. _____________ + ____________ _______________ + ____________ Carbon dioxide WATERSugars Oxygen 6 CO 2 _____________ + ____________ _______________ + ____________ 6 H 2 OC 6 H 12 O 6 6 O 2 →

In addition to water and carbon dioxide, __________________ and __________________ are needed for photosynthesis to happen. chlorophyll light energy

See a video about PHOTOSYNTHESIS 8B

PHOTOSYNTHESIS: Reactants & Products LIGHT ENERGY 6CO 2 + 6H 2 OSUGAR + 6O 2

Visible light is made up of many different _______________of light Your eyes “see” different sizes of waves as different ___________ wavelengths colors

Many people think that plants are green because they absorb and use green light in photosynthesis, BUT.... Myth: Image from:

BUT… We “see” reflected light Light wavelengths that are ___________ off of objects bounce back to our eyes. That is the ___________ we “see” Image modified from: REFLECTED COLOR

This book “looks BLUE” because the dye in this cover _______________ of the wavelengths of light _________ blue. _______ light is ____________ to your eyes and it looks BLUE except absorbs ALL BLUE reflected

The dye in this T shirt absorbs all of the colors __________________________ Red wavelengths are _________________ to your eyes and the shirt looks RED except red reflected GO CATS!

Objects “look BLACK” because black dye ________________ of the wavelengths of light. When wavelengths are absorbed so is the_____________ of the wave. That is why wearing a black T-shirt in the summer feels warmer than wearing a white t-shirt. absorbs ALL ENERGY

The dye in white objects _____________ of the wavelengths of light. _______ energy is ABSORBED so wearing white clothing is “cooler”. REFLECTS ALL LITTLE

Which wavelengths of light are these Flowers REFLECTING? Images by: VanderWal yellowPurple & yellow

green Image by: VanderWal Which wavelengths of light do these LEAVES reflect? So green leaves ____________ the green wavelength of light. REFLECT

Plants gather the sun’s energy with light absorbing molecules called ___________. pigments By: VanderWal

The main energy absorbing molecule in green plants is ___________________ _________________ are plant pigments too. (These look yellow, orange, and red) CAROTENOIDS CHLOROPHYLL

GREEN leaves have BOTH chlorophyll AND carotenoids __________________ but the huge amount of chlorophyll ______ the other colors and leaves usually look green ALL THE TIME hides

In ______, chlorophyll production slows as the trees shut down and photosynthesis stops for winter. FALL

Then we can see the carotinoid colors that are usually _______ by chlorophyll HIDDEN

That’s why leaves LOOK GREEN….. Chlorophyll doesn’t absorb…. it ___________ GREEN light! REFLECTS

Pearson Education Inc, Pusblishing as Pearson Prentice Hall Because light is a form of ___________, any molecule that absorbs light also ___________the energy from the light. ENERGY ABSORBS

Core High School Life Science Performance Descriptors High school students performing at the ADVANCED level: explain the steps of photophosphorylation and the Calvin Cycle; analyze chemical reaction and chemical processes involved in the Calvin Cycle and Krebs Cycle; predict the function of a given structure; High school students performing at the PROFICIENT level: describe and give examples of chemical reactions required to sustain life (…role of enzymes) describe and give examples of chemical reactions required to sustain life (hydrolysis, dehydration synthesis, photosynthesis, cellular respiration, ADP/ATP, role of enzymes); describe the relationship between structure and function High school students performing at the BASIC level name chemical reactions required to sustain life (… role of enzymes) name chemical reactions required to sustain life (hydrolysis, dehydration synthesis, photosynthesis, cellular respiration, ADP/ATP, role of enzymes); recognize that different structures perform different functions;

Remember from CELL BIO Enzymes for PHOTOSYNTHESIS are in the ________________ CHLOROPLASTS

PHOTOSYNTHESIS HAPPENS IN CHLOROPLASTS = sac-like photosynthetic membranes inside chloroplast THYLAKOIDS Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

PHOTOSYNTHESIS HAPPENS IN CHLOROPLASTS Proteins that are part of the thylakoid membrane organize ________________________________ Light absorbing PIGMENTS

Factors that Affect Photosynthesis ____________________ Water is one of the raw materials needed, so A shortage of water can ________________ photosynthesis AMOUNT OF WATER Desert plants and conifers that live in dry conditions have a waxy coating on their leaves to prevent water loss. slow or stop

Factors that Affect Photosynthesis Photosynthesis enzymes function best between 0° C - 35° C At temperatures above or below this range, photosynthesis will slow or stop Conifers in winter may carry out photosynthesis only occasionally TEMPERATURE

Factors that Affect Photosynthesis ____________________ More light increases rate of photosynthesis up to a certain level until plant reaches its maximum rate of photosynthesis LIGHT INTENSITY

THE BIG PICTURE PHOTOSYNTHESIS provides the _____________ we breathe and the __________ heterotrophs (like us) consume to survive _____________ + ____________ _______________ + ____________ Carbon dioxide WATER Sugars Oxygen OXYGEN sugars

Check For Understanding 1.Write the equation for Photosynthesis. 2.Increasing the intensity of light will _______ Photosynthesis. 3.The name of the organelle that allows plants to do photosynthesis is _________. 4.Decreasing the amount of water will _________ Photosynthesis. 5.Plants in Alaska where its colder will do (more or less) photosynthesis than plants in Florida?

Core High School Life Science Performance Descriptors High school students performing at the ADVANCED level: explain the steps of photophosphorylation and the Calvin Cycle; analyze chemical reaction and chemical processes involved in the Calvin Cycle and Krebs Cycle; predict the function of a given structure; predict how homeostasis is maintained within living systems High school students performing at the PROFICIENT level: describe and give examples of chemical reactions required to sustain life (hydrolysis, dehydration synthesis, photosynthesis, cellular respiration, ADP/ATP, role of enzymes); describe the relationship between structure and function explain how homeostasis is maintained within living systems; predict how life systems respond to changes in the environment; High school students performing at the BASIC level name chemical reactions required to sustain life (hydrolysis, dehydration synthesis, photosynthesis, cellular respiration, ADP/ATP, role of enzymes); recognize that different structures perform different functions; define homeostasis;