12
Amarchand Singhvi International School Subject : Science Class : VIII Chapter : Microorganisms: Friend and Foe (Part-2) Topics : Harmful microorganisms, spoilage of food and methods of food preservation Teacher : Ms. Prity Vinjoda E-Learning Programme

Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

  • Upload
    others

  • View
    1

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

Subject : Science

Class : VIII

Chapter : Microorganisms: Friend and Foe (Part-2)

Topics : Harmful microorganisms, spoilage of

food and methods of food preservation

Teacher : Ms. Prity Vinjoda

E-Learning Programme

Page 2: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Contents• Where do microbes live?

• Major groups of microorganism

• Bacteria

• Viruses

• Algae

• Fungi

• Protozoa

• Useful microorganisms

• Harmful microorganisms

• Food Preservation

Amarchand Singhvi International School

Page 3: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Harmful Microorganism

Amarchand Singhvi International School

• Some microorganisms which are not good for us are called harmful microorganism.

• Disease causing microorganisms in humans, plants and animals are called pathogens.

Page 4: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

Disease- causing Microorganisms in Humans

- Pathogens are present everywhere.

- Transferred to our body through - air, water and food or by direct contact with infected body.

- There are some insects and animals which act as carrier of disease causing microbes.

- Diseases that are transferred from unhealthy or infected person to healthy person are called communicable disease.

- (Ex. Cholera, common cold, chickenpox and tuberculosis)

Page 5: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

Diseases- causing Microorganisms in Humans

• Some insects and animals act as a carrier of disease-causing microbes.

• MALARIA- caused by the female anopheles mosquito

that act as the carrier of malaria.

• DENGUE - female Aedes mosquito acts as carrier of

dengue virus.

Page 6: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

Diseases- causing Microorganisms in Animals

•Anthrax is a dangerous human and cattle disease caused by a bacterium. • Foot and mouth disease of cattle is caused by a virus.

Diseases- causing Microorganisms in plants • Disease in plants reduces the yield of crops. • Example - citrus canker caused by bacteria, rusting of

wheat by fungi attack, etc.

Page 7: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

SPOILAGE OF FOOD

• Food that is unfit for human consumption is called spoilt food.

Causes of food spoilage

• Growth of bacteria on food

• Improper cooking

• Improper storage

• Temperature variation

Signs of food spoilage • Foul smell

• Slime

• Sour taste

• Discoloration

• Gas formation

Page 8: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

FOOD PRESERVATION METHODS

Spoilage of food can be prevented by preserving food. Some

methods of food preservation are:

1. Salting: Used to preserve meat, fish,

raw mangoes, tamarind and so on.

Salt inhibits bacterial growth.

2. Adding sugar: Used to preserve fruits

by making jams and jellies. Sugar

reduces the moisture and inhibits

bacterial growth.

Page 9: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

FOOD PRESERVATION METHODS contd..

3. Adding oil and vinegar: Used to

preserve mangoes, carrot and so

on by making pickles. Oil and

vinegar create an environment in

which bacteria cannot live.

4. Storing and packing: Used to

preserve dry fruits, fruits and

vegetables. Prevent attack by

microbes.

Page 10: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

FOOD PRESERVATION METHODS

5. Refrigeration: Used to preserve meat, milk, fruits, and

vegetables and so on. Low temperature inhibits the

growth of microbes.

6. Heating and boiling: Used to preserve milk. Boiling

kills microorganisms.

Page 11: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Amarchand Singhvi International School

FOOD PRESERVATION METHODS

7. Adding chemical preservatives: Used to preserve fruits

and vegetables. Chemical preservatives like sodium

benzoate and sodium metabisulphite prevent the attack of

microbes.

8. Pasteurization:Pasteurization is a method

used to preserve milk in

which milk is heated to

about 700 C for 15 to 30

seconds and then suddenly

chilled and stored. This

prevents the growth of microbes.

Page 12: Ch-5 The Fundamental Unit of Life: Cell...Ch-5 The Fundamental Unit of Life: Cell Author: manoj vinzoda Created Date: 8/27/2020 11:56:07 AM

Note: This presentation is a part of the E-Learning Program of Amarchand

Singhvi International School and is created only for educational purpose.

Compilation & presentation : Ms. Prity Vinjoda

Web support & management : Mr. Deepak Chellani

Technical support : Mr. Shivam Gundecha

E-learning Program Co-ordination:

Mr. Prashant Chaturvedi

Produced by

Mr. Mridul Varma (Principal)

Amarchand Singhvi International School

Parekh Parisar, Ward 7A, Gandhidham – Kutch

Gujarat 370201 India