PHOTOSYNTHESIS AND

CELLULAR RESPIRATION

Celeste Roderno-Desingaño

Came from the word “photo” which means light and “synthesis” which means the building of a complex substance from simpler substances.

Process by which green plants, some bacteria and some protist use solar energy to produce sugar (carbohydrate)

CO2 +H2O C6H12O6 + O2

6CO2 + 6H2O C6H12O6 + 6O2

Photosynthetic Chemical Reaction

Photosynthesis Takes place only in the presence of chlorophyll.

Leaves are the organs of photosynthesis

The epidermis, particularly the lower one, contains openings called stomata that allow gases to move into and out of the leaf.

The body of a leaf is composed of mesophyll tissue, which contain many chloroplasts and carry on most of the photosynthesis for the plant.

Light Reaction Is absorbed by

Chlorophyll a (energy carrier)

Becomes energized chlorophyll that supplies energy to

Split H2O and Add

P

2H O2 ADP (energy

carrier)

Trapped by NADP released forming ATP- stores energy (H acceptor)

Forming

NADPH2

For use in the dark reaction

Dark ReactionCO2

Combines with RDP, a 5-C sugar in the chloroplast(CO2 acceptor)

To form a very unstable 6-C sugar

This splits quickly and forms 2 PGA, a 3-C compound

Combines with 2H supplied by NADPH2 from the light reaction

(energy supplied by conversion of ATP to ADP)

forms

PGAL H2O

Can be used as nutrient or converted

to

RDP

Glucose

Used to combine with CO2

and

By combining 2 molecules of PGAL and substituting H for a

phosphate

Cellular Respiration

A cell releases the energy of glucose

Energy is transferred to the ATP

Involves the burning of organic material

Conversion of food to ATP inside each cell of the body

Cellular Respiration: Chemical Reaction

C6H12O6 + O2 CO2 + H2O + Energy

Cellular Respiration

Cellular Respiration: Three Reactions1. Glycolysis Takes place in the cytosol and not in the organelles Does not require the use of oxygen Glucose is converted to ATP

2. Kreb’s cycle Takes place in the matrix of the mitochondria Requires the use of oxygen and releases carbon dioxide

3. ATP synthesis/ ETC Takes place in the inner membrane of the mitochondria Requires the use of oxygen These reactions pump H+ across the membrane creating

a gradient As H+ enters the matrix, ATP is formed.

ATP Synthesis/Electron Transport Chain

Energy Produced in Cellular Respiration In Glycolysis = 2 ATP

In Krebs Cycle = 2 ATP

In ATP synthesis/ ETC = 34 ATP

Total = 38 ATP

From 38 ATP, the 2 ATP are used to transport products of glycolysis into the mitochondria.

Therefore: 36 ATP are produced for the whole process

Types of Respiration1. Aerobic respiration Stage which requires molecular oxygen Water and carbon dioxide are given off and energy

is released.

2. Anaerobic respiration Occurs outside mitochondria Organisms depend on glycolysis to generate ATP Product of this reaction is ethanol for plants and

lactic acid for animals. This alcohol is formed whenever fruits are processed

into wine through fermentation.

Comparison of Photosynthesis and Respiration

1. Occurs only in the chlorophyll-bearing cells of plant.

2. Needs the presence of light

3. Water and Carbon dioxide are used.

4. Oxygen is given off as a waste product.

5. Food is built or synthesized.

6. The weight of the plant is increased

7. Energy is stored.

1. Occurs in every living plant and animal cell.

2. Occurs at all times.

3. Water and Carbon dioxide are given off as waste products.

4. Oxygen is used in the process.

5. Food is destroyed to release its energy.

6. The weight of the plant is decreased.

7. Energy is released.