Photosynthesis by Mpho Modise

photosynthesis

• Is the process by which plants utilise to produce their own food

Why is Photosynthesis important?Where by plants produce their own foodAll of life is supported by photosynthesis because it begins all food webs and chainsIt also makes oxygen.

Photosynthesis-starts to ecological food webs!

Plants use sunlight to turn water and carbon dioxide into glucose. Glucose is a kind of sugar. Only plants can produce or make their own food because they consist of chlorophyllAutotrophs make glucose and heterotrophs are consumers of it.

Photo-synthesismeans "putting together with light."

How do we know that plants make carbohydrates from just carbon dioxide water and light energy?

• 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.

Experiments!

Photosynthesis

Carbon dioxide + water glucose + oxygensunlight

absorbed by chlorophyll

6CO2 + 6H2O + energy C6H12O6 + 6O2

As can be seen from the equation for photosynthesis, the wood, bark, and root came from water and carbon dioxide.

Check it!

Plants in Action

What is the process that uses the sun’s energy to make simple sugars?

Plant leaves have many types of cells!

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!

Photosynthesis• An anabolic, endergonic, carbon

dioxide (CO2) requiring process that uses light energy (photons) and water (H2O) to produce organic macromolecules (glucose).

6CO2 + 6H2O C6H12O6 + 6O2glucose

SUNphotons

Plants

• Autotrophs: self-producers.• Location:

1. Leavesa. stomab. mesophyll cells

StomaMesophyllCell

Chloroplast

Stomata (stoma)

• Pores in a plant’s cuticle through which water and gases are exchanged between the plant and the atmosphere.

Guard Cell

Guard Cell

Carbon Dioxide (CO2)

Oxygen (O2)

Mesophyll Cell

Cell WallNucleus

Chloroplast

Central Vacuole

Thylakoid Thylakoid Membrane

Thylakoid SpaceGranum

Absorption of Chlorophyll

wavelength

Absorption

violet blue green yellow orange red

References

• http://colleen_snow.azschool.org/teacher/files/documents/photosynthesis[1].ppt

• http://www.csun.edu/science/scale/4th_grade/ppt/photosynthesis.ppt

• Cambpbell & Reece (2010) biology, eighth edition