"Virus" PPT courseware 2

Description

"Virus" PPT courseware 2

discovery of virus

late nineteenth century

Scientist--Ivanovsky

When studying the cause of tobacco mosaic disease, a pathogen smaller than bacteria was discovered - "filtration virus".

Scientists-----Leffler and Frosch

When studying foot-and-mouth disease in animals, it was proven that foot-and-mouth disease is also caused by a "filtration virus."

Early 20th Century

Scientists used electron microscopy to observe that tobacco mosaic virus is a rod-shaped particle.

Conclusion: Viruses are organisms smaller than bacteria.

viral lifestyle

Viruses cannot live independently and must be parasitic in the cells of other organisms. Once it leaves a living cell, the virus's vital activities cease.

After leaving living cells, they become crystals and lose life activities.

Classification of viruses

Viruses are divided into three major categories according to the cells they parasitize:

Animal viruses that specifically parasitize human and animal cells

Plant viruses that specifically parasitize plant cells

Bacterial viruses that specifically live in bacterial cells

structure of virus

The structure of the virus is very simple, with no cellular structure, only a protein coat and internal genetic material.

reproduction of virus

Viruses must parasitize in the living cells of other organisms and rely on the genetic information in their own genetic material to use the materials in the cells to create new viruses. This is its reproduction.

The relationship between viruses and human life

harmful aspects

1. Cause various diseases in humans. Such as influenza, hepatitis, hand, foot and mouth, AIDS, etc.

2. Economic crops, poultry and livestock that harm humans. Avian influenza virus harms the breeding industry, etc.

Advantages

1. Use virus vaccination to make vaccines, etc.

2. Scientists allow certain viruses to carry certain genes from animals, plants or microorganisms into normal cells to achieve the purpose of genetic modification or gene therapy.

The relationship between viruses and human life

Cause disease to humans, animals and plants

Using certain viruses to kill agricultural pests

Use viruses to create vaccines to prevent viruses

Used in genetic engineering: transgenics, gene therapy

Class exercises

1. The virus has a simple structure, consisting of ________ and ________, with no ______ structure.

2. Viruses can only ________ in living cells, rely on the ________ in their own genetic material, and use the materials in the cells to create new viruses. This is its ________.

3. Viruses must live in the cells of other organisms. According to different ________, viruses can be divided into ____ categories.

4. Viruses are so small that their size can only be expressed by ________.

5. True or False:

①Although viruses have no cellular structure, they are living organisms. ( )

②The pathogenic factors of all animals and plants must be viruses. ( )

③The structure of the virus is divided into two parts, namely the outer genetic material and the inner protein. ( )

④Viruses are widely distributed in the biosphere. ( )

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"Virus" PPT courseware download:

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"Virus" PPT download:

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Update Time: 2024-10-03

This template belongs to biology courseware People's Education Edition Biology for Grade 8, Volume 1 industry PPT template

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