Activities of microorganisms are very important to almost every sector of concern to mankind. From a perusal of the foregoing topics, one can find applications (uses) of microorganisms to agriculture, forestry, food, industry, medicine, and environment. The scope and significance of microbiology has enlarged manifold, particularly when importance of environment was realised globally and the word environment was used in a much wider sense in terms of totality to include almost everything, every bit of nature.
a. BACTERIUM or BACTERIA
FUNCTION OF THE PARTS
a. BACTERIUM or BACTERIA
Table 1. Macromolecules that make up cell material
Macromolecule| Primary Subunits| Where found in cell|
Proteins| amino acids| Flagella, pili, cell walls, cytoplasmic membranes, ribosomes, cytoplasm| Polysaccharides| sugars (carbohydrates)| capsules, inclusions (storage), cell walls| Phospholipids| fatty acids| membranes|
(DNA/RNA)| nucleotides| DNA: nucleoid (chromosome), plasmids rRNA: ribosomes; mRNA, tRNA: cytoplasm|
Table 2. Summary of characteristics of typical bacterial cell structures Structure
Flagella| Function(s)Swimming movement| Predominant chemical compositionProtein| Pili|
Sex pilus| Stabilizes mating bacteria during DNA transfer by conjugation| Protein| Common pili or fimbriae| Attachment to surfaces; protection against phagotrophic engulfment| Protein | Capsules (includes “slime layers” and glycocalyx)| Attachment to surfaces; protection against phagocytic engulfment, occasionally killing or digestion; reserve of nutrients or protection against desiccation| Usually polysaccharide; occasionally polypeptide| Cell wall|
Gram-positive bacteria| Prevents osmotic lysis of cell protoplast and confers rigidity and shape on cells| Peptidoglycan (murein) complexed with teichoic acids| Gram-negative bacteria| Peptidoglycan prevents osmotic lysis and confers rigidity and shape; outer membrane is permeability barrier; associated LPS and proteins have various functions| Peptidoglycan (murein) surrounded by phospholipid protein-lipopolysaccharide “outer membrane”| Plasma membrane| Permeability barrier; transport of solutes; energy generation; location of numerous enzyme systems| Phospholipid and protein| Ribosomes| Sites of translation (protein synthesis)| RNA and protein| Inclusions| Often reserves of nutrients; additional specialized functions| Highly variable; carbohydrate, lipid, protein or inorganic| Chromosome| Genetic material of cell | DNA|
Plasmid| Extrachromosomal genetic material| DNA|
* The nucleus is one part of a yeast cell, reports History for Kids. The nucleus of a yeast cell is made up of the lipid envelope of the cell and also the DNA molecule that is protected by this lipid envelope. A lipid envelope consists of big, hydrocarbon molecules, and it prevents the yeast cell’s DNA molecule from getting damaged or broken in any way. To fit all the DNA into the yeast cell, a spiral shape termed a helix is formed. Vacuoles
* Vacuoles are another part of a yeast cell, according to History for Kids. These parts of a yeast cell are defined as small pockets in the cell’s cytoplasm that are used to store food for the cell. Cytoplasm is a thick liquid that is found in the cell membrane; it holds the yeast cell’s organelles. The composition of vacuoles is primarily amino acids and water.
Since the cell’s cytoplasm has salty water, vacuoles have a lipid membrane that works to keep this salty water out. Endoplasmic Reticulum
* The endoplasmic reticulum is comprised of a lipid membrane, which is similar to the composition of the cell membrane around a yeast cell, according to History for Kids. The endoplasmic reticulum of a yeast cell evolved approximately two billion years ago from the cell membrane around the cell’s nucleus. “Endoplasmic” is a word that represents how the reticulum is floating around in the cell’s cytoplasm. “Reticulum” is Latin for net. Thus, the endoplasmic reticulum is a small net that floats around in the yeast cell’s cytoplasm. Lysosomes
* Lysosomes in a yeast cell began their evolution in the cell about two billion years ago. Lysosomes are known as tiny and round bubbles of lipid membrane, indicates History for Kids. The purpose of these lysosomes is to retain hydrogen molecules inside of them; these hydrogen molecules aid in breaking up bigger molecules into smaller ones. This process is basically the digestion of the food of the yeast cell, as well as the breaking up and recycling of garbage and poison in the cell. Lysosomes are known to break down captured bacteria and viruses inside the yeast cell that could destroy it.
One of those scientists studying bacteriophage parts and functions is Sun Qingan from Texas A & M University. He’s been looking at how phages get out of bacterial cells once they have replicated. There are a number of obstacles that are in their way – namely, a cell membrane and a cell wall. But Qingan found out how they are able to destroy the cell wall from the inside The weapon of choice is an enzyme called endolysin. When it is first synthesized it attaches to the membrane and is inactive. But on leaving the membrane it suddenly restructures and gains the power to send the cell wall packing. Qingan draws analogy with Transformers, the science fiction robots that can turn into vehicles or other objects. The key to the biological transformation is a region of the enzyme called the SAR domain which controls the restructuring process and tells the enzyme when to transform.
Qingan hopes that knowing more about the transformation will provides researchers with a possible way of being able to destroy bacterial cells to stop an infection from proceeding. This could be useful for the development of phage therapy.
Courtney from Study Moose
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