Biology .2. Photosynthesis

Front 1

photosynthesis

Back 1

the production of organic compounds from inorganic molecules using light energy trapped by chlorophyll.

Front 2

Carbon Dioxide + Water + Light >> Glucose + Oxygen

Back 2

6CO2 + 6H2O + Light >> C6H12O6 + 6O2

Front 3

Location of Chlorophyll

Back 3

Chlorophyll is present in the chloroplasts.
Chlorophyll occurs in the internal green membranes of the chloroplast.

Front 4

Source of Light in Leaf Cells

Back 4

The natural source of light for photosynthesis is the sun.
Artificial light can also be used if it contains red and/or blue wavelengths of visible light.

Front 5

Source of Carbon Dioxide in Leaf Cells

Back 5

Carbon dioxide in air is the major source.
Carbon dioxide produced by the mitochondria during aerobic respiration is a minor source.

Front 6

Source of Water in Leaf Cells

Back 6

Water from the soil is the major source. Delivered to the leaves in xylem tissue.
Some water is also produced by the mitochondria of leaf cells during aerobic respiration.

Front 7

Role of Photosynthesis in the Biosphere

Back 7

Source of food for plants.
Source of oxygen for aerobic respiration of plants, animals and aerobic micro-organisms.
Direct source of food for herbivores and omnivores.
Indirect food source for carnivores and decomposers.
Original organic source from which fossil fuels formed.

Front 8

Oxygen and Photosynthesis

Back 8

photosynthesis is much faster than aerobic respiration.
Oxygen formation by photosynthesis is far greater than that used by respiration.
The excess oxygen is released from the plant to the atmosphere.
Oxygen produced by photosynthesis = oxygen used in respiration + oxygen released into air.

Front 9

Light Stage

Back 9

Light energy used to make ATP.
Light energy used to produce NADPH from NADP+.
Oxygen gas as a by-product.
Half of the water used as a hydrogen source is recycled

Front 10

Dark stage

Back 10

Carbon dioxide and hydrogen are used to make carbohydrate.
The energy to drive this process comes from ATP.

Front 11

Biochemistry of Photosynthesis

Back 11

.Light energy is absorbed by chlorophyll.
.Absorbed light energy causes the emission of energised electrons.
Some of these electrons can release their energy in a controlled fashion synthesising ATP.
Other electrons are carried into the Dark Stage.
The absorbed light energy is also responsible for the break up of water.
The break up of water releases oxygen, electrons and protons (H+, hydrogen ions).
The oxygen passes from the chloroplast, some will be used by the mitochondria for aerobic respiration and the remainder will be passed into the atmosphere.
The electrons from water run to chlorophyll releasing energy forming ATP.
The protons are released into the ‘pool of protons’ in the chloroplast.
In the Dark Stage electrons from chlorophyll, protons from the pool and carbon dioxide react together forming carbohydrate

Front 12

NADP+

Back 12

NADP+: nicotinamide adenine dinucleotide phosphate

Function: to transfer energy for the formation of complex organic compounds.
The energy is in the form of energy-rich electrons.
In photosynthesis these electrons came from light activated chlorophyll.
NADP+ becomes NADPH in the light stage.
NADPH transfer electrons and protons to carbon dioxide reducing it to carbohydrate.
NADP- is regenerated when NADPH passes on the electrons and proton.