What is Microbiology and Why is it Important

Science of Microbiologyo

• Understanding nature and functioning of the microbial world
• Applying our understanding of the microbial world for the benefit of humankind and planet Earth

Microorganisms:

• Smallest forms of lifeoConstitute the bulk of biomass on Earth (contain lots of Carbon and Nitrogen)
• oCarry out necessary chemical reactions for higher organisms

 Structure and Activities of Microbial Cells

Elements of Microbial Structure:oCytoplasmic Membrane:

• Permeable barrier that separates the inside of the cell from theoutside
• Cytoplasm:Inside of the cell

Aqueous mixture of macromolecules(proteins, lipids, nucleic acids, polysaccharides), inorganic ions, and ribosomes oRibosomes:

• Cell’s protein synthesizing structures
• Cell Wall:Structural strength to a cellPermeableLocated outside of membrane

Stronger than cell membrane

Animal cells do not have cell walls oProkaryotes:

(Bacteria and Archaea)

Consist of small and structurally simple cells

Have 1 chromosome but 1 or more plasmids oEukaryotes:

(Algae, Protozoa, Protists, Fungi)

Larger than prokaryotes

Contain organelles: membrane enclosed cytoplasmic structures

DNA containing nucleus, mitochondria, chloroplasts

Genes, Genomes, Nucleus, and Nucleoid

• Gene: Segment of DNA that encodes a protein or RNA molecule oGenome:Living blueprint of an organism

Eukaryotes genome:DNA is present as linear molecules within nucleus

Prokaryotes genome: Closed-circular chromosome

Chromosome aggregates into nucleoid oPlasmids: Small circles of DNA

Contain genes that confer a special property on the cell (metabolism, antibiotic resistance)

Differ from genes on chromosomes which are needed for basic survival

• Eukaryotes typically have larger genomes than prokaryotes

Activities of Microbial Cells