write in brief about bacteria explaining their types, nutrition, reproduction and their utility as well as harms
Answers
Answer:
Bacteria are single celled microbes. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Instead their control centre containing the genetic information is contained in a single loop of DNA. Some bacteria have an extra circle of genetic material called a plasmid. The plasmid often contains genes that give the bacterium some advantage over other bacteria. For example it may contain a gene that makes the bacterium resistant to a certain antibiotic.
Bacteria are classified into five groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes). They can exist as single cells, in pairs, chains or clusters.
Bacterial shapes
Bacteria are found in every habitat on Earth: soil, rock, oceans and even arctic snow. Some live in or on other organisms including plants and animals including humans. There are approximately 10 times as many bacterial cells as human cells in the human body. A lot of these bacterial cells are found lining the digestive system. Some bacteria live in the soil or on dead plant matter where they play an important role in the cycling of nutrients. Some types cause food spoilage and crop damage but others are incredibly useful in the production of fermented foods such as yoghurt and soy sauce. Relatively few bacteria are parasites or pathogens that cause disease in animals and plants.
how do bacteria reproduce?
Bacteria reproduce by binary fission. In this process the bacterium, which is a single cell, divides into two identical daughter cells. Binary fission begins when the DNA of the bacterium divides into two (replicates). The bacterial cell then elongates and splits into two daughter cells each with identical DNA to the parent cell. Each daughter cell is a clone of the parent cell.
When conditions are favourable such as the right temperature and nutrients are available, some bacteria like Escherichia coli can divide every 20 minutes. This means that in just seven hours one bacterium can generate 2,097,152 bacteria. After one more hour the number of bacteria will have risen to a colossal 16,777,216. That’s why we can quickly become ill when pathogenic microbes invade our bodies.
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Answer:
Microbes occur in five major groups – bacteria, fungi, algae, protozoa and viruses.
2. Microbes can exist in all types of habitats. Bodies of animals and human beings also make good
habitats for microbes. They are among the normal flora (Plants) and are a part of environment.
Microbe – culture means rearing microbes for carrying out study or for some other purpose.
3. Bacteria are unicellular microbes. There are, thousands kind of bacteria, most of which are
harmless.
Bacteria are found everywhere in air, in water in hot spring, in soil and even inside the body of
living organism such as human beings, cat, etc.
In terms of shape bacteria are of four types 1. Bacilli 2. Cocci 3. Spirilla 4. Vibros
In view of nutrition, bacteria have two groups: (a) Autotrophic (b) Heterotrophic
Bacteria reproduce mostly asexually.
Humans use bacteria in many other ways, including: Creating products, such as ethanol and
enzymes. Making drugs, such as antibiotics and vaccines.
Some bacteria cause disease like cholera, leprosy, diarrhoea, pneumonia, TB, typhoid and
whooping cough.
4. Fungi are organisms that lack chlorophyll and so they are unable to make their own food.
Useful Fungi:-
i. They return carbon dioxide to the air which plants use during
photosynthesis.
ii. Fungi like the mushroom and the truffle are eaten as delicacies.
iii. Fungi are used to give flavours to cheese.
5. Algae:- You must have seen a green layer of flora floating on the surface of pond. It is in fact, a
group organisms called algae.
Protozoa:- Protozoa are unicellular organisms with plant – like features. Protozoa are found in
ponds and on animals, plants and even in soil.
Viruses :- Viruses are microbes that live in the cells of other organisms.