Photosynthesis Energy and Life

When do living things need energy? § Just about every activity we do requires energy!! § Energy is needed to sustain life.

Where does energy come from? § Autotrophs - Make their own food § Ex: Plants, Algae § Heterotrophs - Obtain nutrients by eating others § Ex: Humans, mushrooms, fish, cats, dogs

§ In order to live, all organisms including plants must release energy in sugars and other compounds.

Fuel for Living Things § Living things need chemical fuel § ATP is one of the principle chemical compounds that cells use to store and release energy.

What is ATP? § Adenosine Triphosphate § Adenosine – Adenine and Ribose § Triphosphate- 3 phosphate groups

Where is the energy in ATP? § Energy is stored in the three phosphate groups. § In order to release energy to be harnessed for other processes, the bond between the second and third phosphate must be broken.

ATP: Basic Energy Source for Cells! § Can be used for a number of processes § Active transport across cell membranes § Protein synthesis § Nucleic acid synthesis § Response to chemical signals at cell surface § Produces movement by providing energy for motor proteins § Can even produce light! § Muscle contraction

ATP § Only found in small amounts in cells § Great for transferring energy but not for storing large amounts of it long term § A single molecule of glucose stores 90 times as much chemical energy than one molecule of ATP!!!! § More efficient to store a small amount § But, ATP can be regenerated from ADP…

Photosynthesis Process of capturing radiant energy from the sun and converting it to chemical energy – FOOD!

Joseph Priestly 1700’S Placed a jar over a candle and the flame went out Put mint and candle under jar and candle remained lit Plant produced something that kept the candle burning… We know now it was oxygen!

Melvin Calvin 1900’S Used carbon 14 to trace the pathway of carbon as it forms glucose “Calvin Cycle” part of photosynthesis

Notice the illustrations of the plant leaf below. What plant cell organelle do you recognize?

Chloroplast § Chloroplasts are present in plant cells. § They capture the light energy from the sun and convert it into chemical energy (food molecules called glucose, C 6 H 12 O 6 ). § That process is called Photosynthesis

Sunlight is radiant energy Light is needed for photosynthesis

*We see colors of light that are reflected *Other colors are absorbed So for a plant leaf to be green, what color is being reflected????

Gorgeous Fall Color Chlorophyll dies due to lack of sunlight and colder temperatures So… other pigments can be seen In these pictures, what colors are being reflected????

General Equation for Photosynthesis: 6CO 2 + 6H 2 0 → C 6 H 12 O 6 + 6O 2

Photosynthesis takes place in plants, algae and some bacteria The main organ is the leaf in photosynthesis

The photosynthetic organelle... Chloroplast What organ is this found in????

Let’s figure out the equation for Photosynthesis? According to the chloroplast diagram to the left…. According to the chloroplast diagram to the left…. § What is the chloroplast taking in (the reactants)? The same as what we said plants need to survive § What is the chloroplast producing or giving off (the products)? Glucose (C 6 H 12 O 6 )

October 7, 2009 Warm – Up (write the questions) 1.What did Priestley say? 2.What did Calvin do? 3.What is an autotroph? 4.What is a heterotroph? 5.What are the products of photosynthesis? 6.What is the organelle of photosynthesis? 7.What kind of light do we see? ATPADP Contains Adenine Contains Ribose Contains 3 phosphates Contains 2 phosphates “fully charged battery” “partially charged battery” Copy the chart and place an X in the appropriate box…

Absorption of Light Do we see light that is absorbed? Why are leaves green? You are trying to test whether plants grow better in green light or in blue light. –What is the independent variable? –What is the dependent variable? –How would we keep this controlled? –Which plant do you think will grow better – the plant in green light or the plant in blue light? WHY????

Use your manipulatives to create the equation for photosynthesis (Place the correct name of the molecule below it in the equation and make sure your equation is balanced using the correct coefficients) ReactantsProducts Write out your correct balanced equation of photosynthesis.

Does your equation look like the one below?

Flow of Ingredients and Products: Reactants: CO 2 and H 2 O (and sunlight) Products: high Energy compounds and oxygen

Two Parts of Photosynthesis 1. Light-dependent reaction (LDR) *Occurs in the thylakoid membrane 2. Calvin Cycle or light- independent reaction (dark reaction) *Occurs in the stroma

Overview of Photosynthesis

LIGHT and WATER Are used to make OXYGEN Summary of the Light Reaction:

Calvin Cycle MOST COMMON PATHWAY FOR CARBON FIXATION – turning carbon from CO 2 into high energy sugars Occurs in the stroma

Using CO 2 (from the air) to PRODUCE GLUCOSE (what is the formula?)

Factors Affecting the Rate of Photosynthesis Water – If not enough, photosynthesis can’t occur

Light- Rate increases as intensity increases, then levels off (saturated) Temperature– As temperature increases, rate increases up to about 35ºC then drops off due too much water loss ** Make sure to draw the graphs!!!!

September 30, 2010 Write the following exactly as it is shown on your lab table in chalk: PHOTOSYNTHESIS _____ (organ) - _______ (organelle) ReactantsProducts

Warm Up 1.Use your manipulatives and correctly lay out the formula for photosynthesis. 2.Label what is used in the LDR. 3.Label what is used in the Calvin Cycle. 4.Label what is made in the LDR. 5.Label what is made in the Calvin Cycle. 6.Draw and label a CHLOROPLAST. 7.Label where the LDR occurs. 8.Label where the Calvin Cycle occurs.

Check your understanding Explain the process of Photosynthesis using the following terms : carbon dioxidelight energy glucose food oxygen gas process water chloroplastplants Write out your explanation using the above terms.

There is a saying “If you talk to a plant, the plant will grow” Explain how the phrase above is relevant and what process is taking place. Think Pair Share