Question

1. Describe how the causes of sickness and disease were explained in ancient times, prior to the invention of the microscope.

2. Give two examples of foods that have historically been produced by humans with the aid of microbes.

3. What is the main difference between prokaryotes and eukaryotes?

4. Name two types of protists and two types of fungi.

5. How do viruses differ from other organisms?

Answer 1

Answer 1

• In ancient times' humans had a piece of very limited information regarding the causes of disease. Many of them believed that the illness was due to the punishment of the gods or was simply the result of fate.
• On the other hand, some ancient civilizations have an understanding that these diseases might be transmitted due to the things they could not see. This is historical evidence in order to attempt an understanding of the spread of disease.
• Even before the discovery of the microscope, few doctors, scientists, and philosophers have made similar speculations in understanding the invisible forces i.e. microorganism is the causative agent of infection, disease, and death.
• This observation shows an early understanding of the involvement of microorganisms in the spreading of disease.

Answer 2

• Preparation of beverages and other food products required microbial fermentation, which is a process of conversion of sugar/carbohydrates to alcohol, gases, and organic acid by using bacteria, mold, or yeast.
• It is discovered from several archeological sites that the people accidentally learned about fermented food products as early as 7000BC. Therefore they were able to use the fermentation process for the preservation of food as well as for the enhancement of food taste.  The people from a Neolithic village in China were involved in making fermented beverages from rice, honey, and fruits in ancient times.
• It may be possible that the people learned about this fermentation process by drinking old milk which was converted into curd or by drinking old grape juice that was fermented
• Later, after learning the importance of fermentation,  these people used the process of fermentation for the preparation of bread, cheese, yogurt, and wine.

Answer 3

The main difference between Prokaryotes and Eukaryotes are as follows-

Prokaryotes	Eukaryotes
They are usually unicellular but some are multicellular	They are multicellular
They lack membrane-bound organelle such as Nucleus	They contain a membrane-bound organelles
Prokaryotes are much smaller than Eukaryotes	Eukaryotes are large in size
In Prokaryotes, the metabolic activities performed across the cell membrane	In eukaryotes, Mitochondria, and chloroplast performed various metabolic activities
In prokaryotes, the genetic material is not membrane-bound. Prokaryotic DNA is present in Nucleoid	In Eukaryotes, the genetic material is present in the nucleus.

Answer 4

Protists are eukaryotic microorganism fall into Kingdom Protista. Protists are difficult to understand because they resist the universal form of classification. They are animal nor plant, nor fungi.

The 2 types of Protists are

1. Animal-like Protists- these are motile and heterotropic i.e require bacteria or other protists for their food.

Examples are ciliated Paramecium, Amorphous Amoeba

2. Plant Like Protists- They are able to perform photosynthesis due to the presence of chlorophyll in it.

Examples are euglenoids, chrysophytes

Fungi like Protists have also existed.

Fungi are usually classified into four divisions on the basis of the way the  fungus reproduces sexually

1. Chytridiomycota (chytrids),

2. Zygomycota (bread molds),

3. Ascomycota (yeasts and sac fungi), and the

4. Basidiomycota (club fungi).

The (macro) fungi divided into two broad groups called ascomycetes and basidiomycetes, depending on the formation of their sexual spores.

Ascomycetes-  In this group the spores are produced within microscopic cells called asci.

Basidiomycetes- In this group the spores develop on projections that grow outside rom microscopic cells called basidia.

Answer 5

• All the viruses contain a protein and genetic material in the form of DNA or RNA
• Viruses are the connecting link between the living and non-living things. They require host for their survival. without a host, they are non-living organism
• They can only reproduce when attached themselves to the host cells while the bacteria reproduce freely in the environment
• The viruses are smaller and the simplest forms of microorganisms.