"Single-celled Organisms" How cells constitute organisms PPT courseware 3

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"Single-celled Organisms" How cells constitute organisms PPT courseware 3

analyse and compare:

1. How many cells are there in the structure of these organisms? What are the basic structures of cells?

Their bodies are composed of only one cell, including basic structures such as cell membrane, cytoplasm, and nucleus.

2. Try to distinguish whether these small creatures are animals or plants.

Yeast is a single-celled fungus

Chlamydomonas is a single-celled algae that lives in freshwater. There are two flagella at the front end, which can swim freely in the water.

Euglena are single-celled animals with a large number of oval chloroplasts in the cytoplasm. There is an eye point at the base of the flagellum, and there is a swollen part close to the eye point that can sense light. Euglena are phototaxis during movement.

1. Single-celled organisms

There are many organisms in the biosphere that are difficult to see with the naked eye. Their bodies have only one cell, which are called unicellular organisms.

Characteristics: Small individual size.

Most live in aquatic environments. Some live in us.

All life activities are completed within one cell.

Examples: Such as yeast, Paramecium, Chlamydomonas, Euglena, Amoeba, etc.

2. Structure and life of single-celled organisms

Structure and Life of Paramecium

Purpose: To observe the appearance and movement of Paramecium.

Method steps

1. Take a drop of the culture medium from the surface of the Paramecium culture medium, place it on a glass slide, and observe the Paramecium with the naked eye.

2. Cover with a coverslip and observe the morphology and movement of the paramecium under a low-power microscope.

Movement: Cilia (rotating forward in water)

Respiration: epidermis (absorbs oxygen, expels carbon dioxide)

Digestion: oral groove (food enters), food vesicle (food is digested) anus (food residue is discharged)

Excretion: collection tube (collects excess water and waste in the body) telescopic bubble (discharges excess water and waste from the body) epidermis (excretes from the body through the epidermis)

Reproduction: cell division

3. The relationship between single-celled organisms and humans

Paramecium also plays a certain role in sewage purification. According to statistics, a Paramecium can form approximately 60 food bubbles per hour, and each food bubble contains approximately 30 bacteria. Therefore, a Paramecium can swallow approximately 43,000 bacteria per day. .

1. Beneficial:

Single-celled organisms are food for fish

Paramecium can purify sewage

2. Harm:

It parasitizes the human body and harms human health. Such as Plasmodium, Entamoeba dysenteriae

Cause red tide and harm fisheries

Class exercises

1. Fill in the blanks

1. Paramecia are __________, __________ and __________ from outside to inside.

In addition, there are structures such as __________ (responsible for movement) and __________ (responsible for digestion).

2. Although single-celled organisms are only composed of __________ cells, they can independently complete life activities such as __________, __________, __________, and __________.

3. One paramecium can eat about __________ bacteria every day, so it has __________ effect on sewage.

4. Like multicellular organisms, single-celled organisms can also __________ beneficial stimuli and __________ harmful stimuli.

1. The way bacteria reproduce is usually: [ ]

A. Sporogenesis B. Fragmentation C. Schizogony D. Conjugation

2. Approximately how many bacteria can a paramecium eat in a day[ ]

A, 40 B, 400 C, 4000 D, 40000

3. The cause of red tide is[ ]

A. Garbage dumped by fishermen on sea boats

B. Wastewater dumped by industrial ships

C. Massive proliferation of microorganisms in the ocean

D. The body of the fish was torn apart by sharks, and the blood dyed the sea water red.

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For more information about the PPT courseware "How Single-Celled Biological Cells Constitute Organisms", please click the "How Single-Celled Biological Cells Constitute Biological Organisms" ppt tag.

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Update Time: 2024-09-23

This template belongs to biology courseware People's Education Edition seventh grade biology volume 1 industry PPT template

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