i. Citrus canker - caused by bacteria
ii. Potato blight disease - caused by fungi.

Some algae have photosynthetic pigments like fucoxanthin (brown), Xanthophylls (yellow), Phycoerythrin (red), Phycocyanin (blue).

i. Aerobic bacteria (requires oxygen)
ii. Anaerobic bacteria (Does not requires oxygen)

i. They respond to heat, chemicals, and radiations.
ii. They show irritability.

Virus, Bacteria, fungi, Algae and protozoa

1. It is a process for preservation of liquid food.
2. This method was invented by Louis Pasteur in 1862.
3. Milk is heated up to 70⁰c to kill the bacteria and it is cooled to 10⁰c to prevent the growth of remaining bacteria.
4. Then milk is stored in sterilized bottles in cold places.

Causative agent - Aphthovirus
Symptoms:
1. Fever
2. Blisters in mouth
3. Weight loss
4. Decreased milk production.

The conversion of organic compounds such as carbohydrates into simpler substances by microbes usually under anaerobic conditions.
Eg. Sugars in grapes are fermented by using yeast.

i) Ciliate - presence cilia eg. Paramecium
ii) Flagellates - Presence of flagella. eg. Euglena.
iii) Pseudopods - presence of pseudopodia eg. Amoeba.
iv) Sporozoans - Parasites eg. Plasmodium.

i) They are inactive when present freely in the environment.
ii) They can be crystallized and stored.
iii) Cytoplasm is absent.

i. Amoeba is a unicellular microscopic organism.
ii. It is found in ponds.
iii. Amoeba is irregular in shape.
iv. It has cell membrane, cytoplasm, and nucleus.
v. It is a protozoan that moves by means of pseudopodia.
vi. It helps to catch its prey.
vii. The body flows around the food particle and engulfs it.
viii. Contractile. Vacuoles help in excretion.
ix.  Amoeba reproduces by means of fission and sporulation.

A. Traditional Techniques:
i. Fermentation: Fermentation is the microbial conversion of starch and -sugar into alcohol. It makes foods more nutritious and palatable
ii. Pickling: It is of two types
1. Chemical pickling: Food is placed in an edible liquid that kills bacteria and other microorganisms, Eg; Vinegar, alcohol, vegetable oil.
2. Fermentation Pickling: Bacteria in the liquid produce organic acid as preservation agent that produces lactic acid due to the presence of Lactobacillus.
iii. Boiling: Boiling liquid food items kill all the microbes eg; Milk & water
iv. Sugaring: Sugar is used to preserve fruits in an antimicrobial syrup with fruit such as. apple, pears, peaches.
B. Modern techniques:
i. Pasteurization
1. It is a process for preservation of liquid food.
2. Milk is heated upto 700c to kill the bacteria and it is cooled to 100c to percent the growth of remaining bacteria.
3. Then Milk is stored in sterilized bottles in cold places.

I. Making of Bread:
i. Yeast is used in bakeries to make bread and cakes.
ii. They are added to the dough to produce CO₂ which makes the dough rise.
iii. Chlorella is rich in proteins and Vitamins is added to the dough which enriches the bread with nutrients.
II. Preparation of Curd and Cottage Cheese:
i. Lactose is the milk gets turned into lactic acid by the action of lactobacillus.
ii. Therefore the milk becomes thick.
iii. When the curd is processed cottage cheese is obtained.
III. In Human Intestine:
i. Lactobacillus acidophilus that lives in the human intestine helps in digestion of food and fight against harmful disease-causing organism.
ii. E.cole bacteria in human intestine help in synthesizing Vitamin K and Vitamin B complex.

1. Yeast is found freely in the atmosphere.
2. It grows in all kinds of media containing sugar.
3. The cell is oval in shape containing cell wall and a nucleus
4. The cytoplasm is granular and has vacuoles, organelles, glycogen, and oil globules.
5. It helps in fermentation with the help of the enzyme zymase.
6. It reproduces by budding.