How To Convert Atom To Osmosis

Bacteria Definition

Bacteria are single-celled microorganisms with prokaryotic cells, which are single cells that practise not accept organelles or a true nucleus and are less complex than eukaryotic cells. Leaner with a capital B refers to the domain Bacteria, ane of the three domains of life. The other two domains of life are Archaea, members of which are also single-celled organisms with prokaryotic cells, and Eukaryota. Bacteria are extremely numerous, and the total biomass of leaner on World is more than all plants and animals combined.

Development of Bacteria

Bacteria beginning arose on Earth approximately 4 billion years agone, and they were the first forms of life on Earth. For 3 billion years, leaner and archaea were the virtually prevalent kinds of organisms on World. Multicellular eukaryotes did not appear until around one.6-2 billion years ago. Eukaryotic cells, which make upwardly all protists, fungi, animals, and plants, also contain what was once bacteria; it is idea that the mitochondria in eukaryotes, which produce free energy through cellular respiration, and chloroplasts in plants and algae, which produce energy through photosynthesis, both evolved from bacteria that got taken upwards into cells in an endosymbiotic (mutually benefiting) relationship that became permanent over fourth dimension.

Leaner Characteristics

Bacteria are unmarried-celled organisms. They lack organelles such as chloroplasts and mitochondria, and they practise non take the truthful nucleus found in eukaryotic cells. Instead, their Dna, a double strand that is continuous and circular, is located in a nucleoid. The nucleoid is an irregularly shaped region that does not accept a nuclear membrane. Bacteria too have a cell membrane and a cell wall that is often fabricated of peptidoglycan. Together, the cell membrane and cell wall are referred to as the prison cell envelope. Many leaner need a cell wall in order to survive.

Reproduction occurs through binary fission, which is the splitting of a bacterial jail cell afterward it reaches a certain size. Bacteria reproduce asexually, and then the two girl cells that outcome from binary fission have the same DNA as the parent cell. However, some bacteria tin also exchange genetic material amongst ane some other in a process known every bit horizontal gene transfer. This method involves two already existing leaner; it is non a grade of transmission from parent to kid.

Bacteria Shapes

Bacteria come in a myriad of shapes. The iii main shapes of bacteria are coccus, spiral, and bacillus.

Leaner can also be other shapes such as filamentous (long and thin), foursquare, star-shaped, and stalked. This diagram depicts the numerous shapes of leaner.

Types of Bacteria

The jail cell wall also makes Gram staining possible. Gram staining is a method of staining leaner involving crystal violet dye, iodine, and the counterstain safranin. Many bacteria tin be classified into one of two types: gram-positive, which show the stain and appear violet in color under a microscope, and gram-negative, which merely evidence the counterstain, and appear red. Gram-positive bacteria appear violet because they have thick cell walls that trap the crystal violet-iodine circuitous. The sparse jail cell walls of gram-negative bacteria cannot hold the violet-iodine complex, but they can agree safranin. This makes gram-negative bacteria appear red under Gram staining. Gram staining is used for general identification of leaner or to detect the presence of certain bacteria; it cannot be used to identify bacteria in any specific style, such as at a species level. Examples of gram-positive leaner include the genera
Listeria, Streptococcus, and Bacillus, while gram-negative bacteria include Proteobacteria, dark-green sulfur leaner, and blue-green alga.

Examples of Bacteria

Escherichia coli
is one example of a common species of bacteria. Information technology is bacillus-shaped and found naturally in the intestines of many animals including humans, where it produces vitamin K and b-complex vitamins.
E. coli
is also oftentimes used in laboratory research since it reproduces chop-chop and is hardy. Most strains of
E. coli
are harmless to humans, but some can cause infection.
E. coli
infection can result in gastrointestinal problems similar diarrhea, and in more than astringent cases, bacterial meningitis or pneumonia can occur.

Lactobacillus acidophilus
is another bacillus-shaped species of bacteria naturally found in places like the intestines and vagina, where it protects confronting harmful bacteria. It is a probiotic, a bacterium found in certain foods like yogurt and other fermented foods that is consumed in order to assistance blot nutrients and furnish the body’s supply of “proficient” leaner. Information technology tin can also be consumed in small amounts by people with lactose intolerance in order to aid them eat lactose.

Some bacteria can be extremely harmful, such as
Clostridium botulinum, the leaner that causes botulism.
C. botulinum
produces the neurotoxin botulinum, which is responsible for the symptoms of botulism. Symptoms include blurred vision, nausea, trouble animate, muscle weakness, and paralysis. Botulinum toxin is the deadliest known toxin; merely one kilogram of botulinum would be deadly enough to kill the entire human population.

• Prokaryote
  – An organism that has a simple prokaryotic jail cell; bacteria and archaea are prokaryotes.
• Binary fission
  – The method by which bacteria reproduce asexually through dividing.
• Probiotic
  – A bacterium that helps maintain a healthy digestive tract when consumed.
• Horizontal gene transfer
  – Gene transfer between two organisms that are not parent and offspring.

Quiz

i. How do leaner reproduce?

A.
Sexual reproduction
B.
Horizontal gene transfer
C.
Binary fission
D.
Mitosis

2. Which is not one of the iii primary shapes of bacteria?

A.
Coccus
B.
Bacillus
C.
Spiral
D.
Star

three. When did bacteria first begin to exist on Earth?

A.
4 billion years ago
B.
ii billion years agone
C.
1.6 billion years ago
D.
1 billion years ago