Overview of Photosynthesis The Big Questions What kind

Overview of Photosynthesis

The Big Questions What kind of energy does a plant rely on to do photosynthesis? How does the plant capture and store that energy? Why do other organisms need photosynthesis to occur?

Photosynthesis is… Circle one: Exergonic/Endergonic Light Energy Chloroplast CO 2 + H 2 O Sugars + O 2 + enzymes, chlorophyll 6 CO 2 + 6 H 2 O + sunlight ---------------> C 6 H 12 O 6 + 6 O 2

PHOTOSYNTHESIS • Autotrophic Process: Plants and plant-like organisms store their energy (glucose) from sunlight. • Stored as carbohydrate in their bodies. • Enzyme-driven process • 6 CO 2 + 6 H 2 O + sunlight C 6 H 12 O 6 + 6 O 2

Where does photosynthesis occur? • Leaves!

Plant leaves have many types of cells!

Where does photosynthesis occur? • Plant leaves (& green parts) • Specifically, in mesophyll cells (these contain chloroplasts)

Plant Cells

The photograph below is an elodea leaf X 400. Individual cells are clearly visible. The tiny green structures within the cells are chloroplasts this is where photosynthesis happens.

Chloroplasts make the sugars!

Plants Leaves are green because they contain the pigment: chlorophyll Leaves have a large surface area to absorb as much light as possible "Thanks for the Glucose!"

Chloroplasts make the oxygen!

How do other leaf parts help? • Stomates- openings allow gases to move in (carbon dioxide) and out (oxygen) • Veins- made of two types of tubing • Xylem tubes bring water to the leaves from the roots • Phloem tubes carry away glucose from mesophyll cells

Plant Stomates

Close-up View of a Stomate (guard cells are mostly hidden) Can we see the veins (phloem, xylem) in plants?

Why is Photosynthesis important? Makes organic molecules (glucose) out of inorganic materials (carbon dioxide and water). It begins all food chains/webs. Thus all life is supported by this process. It also makes oxygen gas!!

Photosynthesis-starts to ecological food webs!

Photo-synthesis means "putting together with light. " Plants use sunlight to turn water and carbon dioxide into glucose Plants use glucose as food for energy and as a building block for growing. Autotrophs make glucose and heterotrophs are consumers of it.

How do we know that plants make carbohydrates from just carbon dioxide water and light energy? Experiments! • For example: Jan Baptisa van Helmont (1648) planted a willow branch weighing 5 pounds into 200 pounds of soil and then after 4 years the tree weighed 169 lbs. and the soil was still nearly 200 lbs.

Photosynthesis sunlight Carbon dioxide + water absorbed by chlorophyll glucose + oxygen 6 CO 2 + 6 H 2 O + energy C 6 H 12 O 6 + 6 O 2 As can be seen from the equation for photosynthesis, the wood, bark, and root came from water and carbon dioxide.

Plants in Action Check it! What is the process that uses the sun’s energy to make simple sugars?

Light and Pigments • Light is energy (your hand warms up in the sun!) • Pigments absorb light energy • For a day in the sun, what color shirt might you choose? Why? • If a shirt is green, what color light does it absorb? What color light does it reflect?

PHOTOSYNTHESIS • Why do we see green? • Green color from white light reflected NOT absorbed • Chloroplast: organelle responsible for photosynthesis • Chlorophyll: located within Chloroplast (Green pigment)

Visible light is only a small part of the electromagnetic spectrum (all forms of light).

• LIGHT behaves as if it were composed of "units" or "packets" of energy that travel in waves. • The wavelength of light determines its color.

Chlorophyll: A Light Absorbing Pigment The Solar Panel Chemical!

Photosynthesis Glucose provides the energy and carbon needed to make other plant materials like wax and proteins.

• In plants and simple animals, waste products are removed by diffusion. Plants, for example, excrete O 2, a product of photosynthesis.

EQUATION FOR PHOTOSYNTHESIS WATER 6 CO 2 + 6 H 2 O + ENERGY CARBON DIOXIDE OXYGEN C 6 H 12 O 6 + GLUCOSE 6 O 2

Now what do plants do with glucose? • Cellular Respiration so the cells can do work! • C 6 H 12 O 6 + 6 O 2 --> 6 H 2 O + 6 CO 2 + ATP • Store the extra glucose in… • Maple syrup • Sap • Fruits