Do Now What is photosynthesis and what is

the chemical formula for it?

The site of photosynthesis - The Chloroplast • Organelle found in plant cells

• Each plant cell contains many chloroplasts

• Where glucose, the plants food is made, by absorbing light energy and converting it to chemical energy

Photosynthesis and the Chloroplast

Photosynthesis has two parts:

1. Light-Dependent Reactions – require light, takes place in the thylakoids.

1. Light-Independent or Dark Reactions (Calvin Cycle) – no light is needed, takes place in the stroma.

Chlorophyll

• Chlorophyll found within the thylakoid of the chloroplast absorbs the sun light (energy/photons)

• When sun’s rays…blue and red only are captured, the green rays are reflected and thus plants are seen as green.

Interpret the Graph, which colors are being absorbed?

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Light-dependent Reactions

Light-dependent: converts light energy into chemical energy; produces ATP molecules to be used to fuel light-independent reaction

• Sunlight hits chlorophyll, Chlorophyll’s electrons get excited and is transformed into energy - ATP and NADPH which is used in the light-independent reactions or Calvin Cycle.

• During the light-dependent stage, two molecules of water are split, and as a result oxygen gas is released into the atmosphere.

Oxygen a waste product of photosynthesis

Summary—Light Dependent Reactions

a. Overall input

light energy, H2O.

b. Overall output

ATP, NADPH, O2 .

Light-Independent reactions (Calvin Cycle)

• These are called the Dark reactions because they do not require sunlight to occur. BUT they do require the ATP and NADPH from the light-dependent reactions to occur.

• During the light-independent

reactions, CO2 enters the plant and mixes with the ATP and NADPH to form a 6 carbon sugar called GLUCOSE.

• This cycle has to happen 6 times

just to get 1 molecule of glucose

Summary—Light-Independent Reactions (Calvin Cycle)

a. Overall input

CO2, ATP, NADPH.

b. Overall output

glucose.

Let’s Review the Basics

• Glucose is the product of Photosynthesis as well as Oxygen…However, plants store the glucose and release the oxygen.

• Photosynthesis happens in the chloroplasts. – Light-dependent Reactions, light needed, happens in the

thylakoid – Light-independent Reactions (Calvin Cycle), light is not

needed, happens in the stroma • Light-dependent uses light to form ATP, NADPH, and releases

oxygen as a waste product. • Light-independent (Calvin Cycle) brings in carbon dioxide and

uses the ATP, NADPH made from light-dependent reactions to make glucose.

• Plants make glucose and use it for cellular respiration, food, and building macromolecules such as cellulose that it needs for growth and development.

In your own words write a summary of the chemical processes of photosynthesis

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PHOTOSYNTHESIS

• What affects photosynthesis?

– Light intensity: as light increases, rate of photosynthesis increases

PHOTOSYNTHESIS

• What affects photosynthesis?

– Carbon Dioxide: As CO2 increases, rate of photosynthesis increases

PHOTOSYNTHESIS

• What affects photosynthesis?

– Temperature:

• Temperature Low = Rate of photosynthesis low

• Temperature Increases = Rate of photosynthesis increases

• If temperature too hot, rate drops

Let’s take a look at how plants and other cells use the glucose

that is produced.

Q: Energy is packaged in glucose during the process of photosynthesis. However, the glucose molecule is bound together. Do you think cells can use this glucose in its current form?

Q: So what has to happen to the glucose, if it is bound together, in order for cells to use it?

Complete the following chart

Description of Process Reactants Products

Photosynthesis

Cellular

Respiration

What do you notice about the reactant and products of cellular respiration in comparison to the reactant and products of photosynthesis?

Structure Plant Cell Animal Cell

Cell membrane

Cell wall

Mitochondria

Chloroplast

Nucleus

Vacuole

Lysosome

One more comparison: Complete the table below with a yes/no response

Compare and Contrast an animal with a plant cell (include what you have learned about cell structure, cellular respiration, and photosynthesis).