Chapter 10-Photosynthesis

Chapter- 10
Photosynthesis

 

Photosynthesis Equation

CO2 + H2o + Minerals + Energy of Light >>>> C6H12O6 + O2

 

Autotrophs
(Producers)

Autotrophs- make their own food. There are 2 types of autotrophs

1.Photoautotrophs-Those that require light to make their food, such as all higher plants.

2. Chemoautotrophs- Do not require light to make their food. Sulfur and Iron bacteria.

 

Heterotrophs
(Consumers)

Heterotrophs- cannot make their own food. They must eat.

There are 5 types of Heterotrophs:

1.Herbivores- plant eaters

2.Carnivores- meat eaters

3.Omnivores- plant and meat eaters

4.Saprophytes- (decomposers)-dead material)

5.Parasites- feed on living material ( they are harmful)

 

Where does Oxygen
Come From?

CO2 + H2O + Light Energy>> C6H12O6 + O2.

Where does the O2 come from? The H2O or the CO2? How can we find out?

By using radioactive O18.

Feed one plant radioactive water

Feed another plant radioactive CO2

 

Stages of Photosynthesis
Fig. 10.4

1.Light Reaction- Light is required. Three things are produced during the light reaction-------- O2, ATP and NADPH. NADPH stands for: Nicotinamide adenine dinucleotide phosphate. The light reaction ccurs in the granum and thylakoids of the chloroplast.

2.Dark reaction (also known as the Calvin cycle) does not require light. This is where glucose (C6H12O6) is produced.Occurs in the stroma of the chloroplasts.

 

Ultraviolet Radiation

There are three types of UV radiation- UVA, UVB and UVC. All three are harmful and can cause the following health problems:

Skin cancer and other skin disorders

Cataracts and other eye damage

Immune suppression

 

Ozone
O3

Fortunately for life on earth, stratospheric ozone screens most, but not all, harmful UV radiation

UVA-not absorbed by the ozone layer

UVB-Partially absorbed by the ozone layer

UVC-Completely absorbed by oxygen and ozone in the atmosphere

 

Protection from UV Radiation

Limit time in the midday sun

Watch the UV index

Wear sunglasses that block UVA and UVB

Wear a hat

Protect other areas of your body with proper clothing

Wear sunscreen (SPF of 15)

Avoid sunlamps and tanning parlors

 

Light Reaction

Pq- Plastoquinone

Pc- Plastocyanin

Plants also carry out respiration

Remember- plants use part (50%) of the glucose and oxygen that they produce to carry out their own internal cellular respiration

Photosynthesis produces 160 million tons of carbohydrates per year

Enough to produce 60 trillion copies of your text book

 

No other chemical process on the earth can match the output of photosynthesis

There would be no life without photosynthesis