Chap 1 f5 Sci Student

7/29/2019 Chap 1 f5 Sci Student

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SUBJECT: SCIENCE FORM: 5

TOPIC: MICROORGANISMS AND THEIR EFFECTS ON LIVING THINGS

- Some living things are big but some living things are very small(tiny).

- They are so tiny that they cannot be seen with the eye.

- They can be seen only under a .

-We called these tiny living things .

- are different in , and are found .

- Microorganisms are things because they carry out processes.

- There are 4 main types of microorganisms – , , and

viruses.

CLASSIFICATIONS OF MICROORGANISMS

o Type of microorganisms

- Definition:

Tiny living things that be seen by naked eyes, but can be seen bymicroscopes. They are also known as .Some of microbes are , but some of them are too

- Classification:There are 5 main groups for microbes:a) Bacteria Beruk

b) Protozoa Pergi

c) Fungi Filipina

d) Algae Angkat

e) Viruses Van

o Characteristics of various type of microorganisms

1. Bacteria

Definition:smallest living things can be seen by microscope , have the

simplest , and have the number among the five groupsof microbes.

Size:Consists only one (about 0.5 to 10 micrometer)Shape:There are general shapes:

a) Cocci Cium

b) Bacili Baboon

c) Spirilia Sampai

d) Vibrio Vietnam

Structure:

Nutrition:Some bacteria have , so they can make their food by process.Some of bacteria don’t have chlorophyll, so they have to be:a) - get food from mattersb) - get food from living organisms



Respiration:Some of bacteria carry out respiration, and some of them carry outanaerobic respiration.

Reproduction:a) By fissionb) By .

Habitat:Bacteria live in any places.

2. Protozoa

Definition:Animals which are made up of only cell. They are .Example: amoeba , paramecium and etc.

Size:

Consists only cell (about to micrometer)

Shape:Have various shapes, but mostly they have shape (no shape)

Structure:

Nutrition:Some of protozoa live as . E.g: plasmodium. Some of them obtainfood from their . E.g: amoeba and paramecium. Some of protozoamake their food.

Respiration:All of protozoa carry out respiration

Reproduction:

a) By fissionb) By reproduction (spore formation)c) By reproduction (conjugation)

Habitat:Protozoa live in any ponds, river, damp soils or in otherorganisms, and they lives in .

Exercise:

1. Name the five main groups of microorganisms2. Bacteria can live in unfavorable conditions. Under such conditions,

they…………….3. Size of protozoa is about……………………4. What is the shape of paramecium? ............................

3. Fungi

Definition:Plants which do not have . They include , moulds andyeast. They do not have , or .

Size:Some of them are (i.e mushroom), and some of them are (i.emoulds and yeast)

Shape:

Have various shapes: i- ballii- long .iii- -shaped

Structure:



Nutrition:Most of fungi live as (i.e moulds) or (i.e mucor) .

Respiration:Most of fungi carry out respiration

Reproduction:a) By .

Fungi such a mushrooms form spores within their caps. Mucor formsporangium (containing spores). When it ripe, it bursts open and dispersesthe spore.

b) By .

Habitat:Fungi live in dark habitats.Example: Mucor grows on damp stale bread placed in the dark

4. Algae

Definition:Very simple plants which have . Algae do not have , orleaves

Size:Some of them are (i.e ), and some of them are (i.e ,euglena and etc)

Shape:Have various shapes: i- ball

ii- filamentsiii- -shapediv- -like structure

Nutrition:Algae possess , so that they can make their own food byphotosynthesis.

Respiration:Most of fungi carry out respiration

Reproduction:

a) By reproduction ( fission)b) By asexual reproduction ( )Algae reproduced by breaking a long filament into two.c) By reproduction ( )

Habitat:Algae live in water, salt water, damp soil or on damp bark of

trees.

5. Virus

Definition:Smallest microorganisms and it do not , do not wasteproducts, and do not possess , cell membrane and .

Size:About 0.02 – 0.4 micrometer, and can be seen only by microscope

Shape:Have various shapes, maybe in , or rod-shaped

Structure:

Nutrition:Viruses live as in living cell.

Habitat:Viruses live only in cell.



Exercise:1. How do fungi continue its generation under adverse condition?2. Why algae look greenish?3. What a different between algae and tree?5. State 3 properties of viruses which are not characteristics of living things

FACTOR WHICH AFFECTS TO THE GROWTH OF MICROORGANISM

There are main factors that affect the growth of microorganism:

1. Nutrients

Microorganisms need to live, and they get it by being:

a) .b) .c) .

2. Humidity

Microorganisms need living place with level of humidity. That means,they need or water to live, and they will if they do not get water for a period of time.

However, some bacteria can live in a place without presence byforming spores. For , they form (spore with outer ring).

3. Light

Most of , and and some of bacteria prefer dim or darkhabitat, while algae and few of bacteria tend to live in place since theyhave to carry out process.

4. Temperature

Most suitable temperature for the microorganism’s growth and live is about(human’s body temperature).

High temperature will microorganisms, while temperature makesthem inactive.

5. pH value

Most of microorganisms prefer to live in medium (pH = 7)

In very (pH = 1 to 3) and very (pH = 12 to 14) conditions,most of microorganisms will be killed.

USEFUL MICROORGANISMS

1. In the Digestion of Food

Some bacteria and protozoa help (e.g: rabbit, goat, cows and etc)and termites digest their food

They produce an called to help herbivores and termitesdigest cellulose into glucose

2. In Decay

2.1 Formation of humus

Some of bacteria and fungi decompose matter intohumus

2.2 Production of biogas and fertilizers

Some of bacteria decompose waste (e.g: waste from oilpalm, paddy and coconut) and turn it into gas

2.3 Disposal of oil spills

Some of bacteria break up spills and decompose it into less harmfulsubstance.

3. In Medicine

3.1 Antibiotics

There are 2 common antibiotics in world, which are:



a) (prepared from penicillium notatum bacteria)b) (prepared from streptomyces griseus bacteria)

Antibiotics can only bacteria

3.2 Vaccines

Vaccines are prepared from or very weak and . Itused to stimulate the body to produce antibodies.

Vaccination refers to an containing certain vaccines that can prevent aperson being infected to a certain . Example: BCG injection for drycough disease.

4. In Agriculture

4.1 Maturing of tobacco leaves

Bacteria used to make tobacco leaves mature, so that they can emit desirablesmell and taste.

4.2 Nitrogen cycle

Figure 4.2- A (Simple nitrogen cycle)

4.3 Productions of chemicals from algae

Some algae used to produce beneficial chemicals for human beings. For theexample:

a) beta-carotene – which has anti cancer propertiesb) fatty acids – which make cholesterol level in human’s blood become low

5. In Industry

5.1 Making breads and cakes

Yeast is used in the making breads and cakes. It is mixed with flour, sugar and water; and made into dough

Yeast will reacts with sugar to produce (ethanol), dioxide andenergy. By the way, this process is known as .

Carbon dioxide released makes the dough rise, so that breads and cakesbecome very soft.5.2 Making ethanol

Yeast is also used to produce alcohol ( ) instead of carbon dioxide.

5.3 Production of vinegar, and yoghurt

Vinegar ( acid) is prepared by using bacteria to change ethanol into

ethanoic acid.

Yoghurt (contains acid) is prepared by the action of on milk.Bacteria will reacts with in milk and turns it into lactic acid.

5.4 Production of soy sauce

Soy sauce is produced from the of a mixture containing mould,

yeast, flour and soy beans. Salt is added to make it become salty.

Denitrifying

bacteria

Nitrifying

bacteria

Bacteria of decay

Nitrogen-fixing bacteria



Exercise:1. List all factors affect to the growth of microorganism2. Which microorganisms that can live in bright place?3. Tell the range of air humidity which most of microorganisms are very active.

Chap 1 f5 Sci Student

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