VTPB 405 Study Guide - Fall 2018, Comprehensive Midterm Notes - Vibrio Cholerae, Tiny Titans, Streptococcus
12 Oct 2018
School
Department
Course
Professor
VTPB 405
MIDTERM EXAM
STUDY GUIDE
Fall 2018
Exploring the Microbial World
Microorganisms, Tiny Titans of the Earth
• Life forms too small to be seen by human eye
◦ Diverse in form/function
◦ Inhabit every environment that supports life
◦ Many single-celled, some form complex structures, some
multicellular
◦ Live in microbial communities
• Activities are regulated by their interactions with each
other, the environment and other organisms
• Oldest form of life
• Major fraction of Earth's biomass
◦ Essential to sustain life on Earth (oxygen generation)
• Surround plants and animals
• Affect human life (infectious diseases, food and water, soils, animal
health, fuel)
◦ Most interactions are positive impacts
◦ Only a few have negative impacts
• Tools for study
◦ Microscopy
◦ Culture: cells grown in/on nutrient medium
• Have to be able to grow them so we can study them
◦ Medium: liquid/solid mixture containing all required nutrients
◦ Growth to form a visible colony
• Microbiology: the science that studies who microbes are, how they
work and what they do
◦ Studying fundamental life processes
• Molecular biology and biochemistry
• Genomics and molecular genetics
Structure and Activities of Microbial Cells
find more resources at oneclass.com
find more resources at oneclass.com
• The Microbial Cell: a living compartment that interacts with the
environment and other cells
• Elements of microbial structure
◦ All cells have the following in common:
• Cytoplasmic cell membrane: a barrier that separates
the inside of the cell from the outside environment
• Cytoplasm: aqueous mixture of macromolecules, small
organics, ions, and ribosomes inside cell
• Ribosomes: protein-synthesizing structures
• Cell wall: present in some microbes; confers structural
strength
• Prokaryotic versus eukaryotic cells
◦ Prokaryotes
• Bacteria and archaea
• No membrane-enclosed organelles (membrane-
enclosed structures), no nucleus
◦ Eukaryotes
• Plants, animals, algae, protozoa, fungi
• Contain organelles
• DNA enclosed in a membrane-bound nucleus
• Genes, genomes, nucleus, and nucleoid
◦ Genome: a cell's full complement of genes
◦ Eukaryotic DNA
• Linear chromosomes within nucleus
• Much larger/more DNA (up to billions of base pairs)
◦ Prokaryotic DNA
• Generally single circular chromosome that aggregates
to form the nucleoid region
▪ Always exceptions, some have two circular
chromosomes, others have linear chromosomes
• May also have plasmids (extrachromosomal DNA) that
confer special properties (antibiotic resistance)
• Small, compact
• Activities of microbial cells
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Microorganisms, tiny titans of the earth: life forms too small to be seen by human eye, diverse in form/function, many single-celled, some form complex structures, some. In nature, cells typically live in microbial communities. In most: motility: many cells move through self-propulsion, differentiation: some microbes modify structures to form specialized cells. Intercellular communication: some microbes respond to other microbes: genetic exchange. In humans, 1-10 microbial cells per human cells. Improving food safety, preservation: dairy products, other food products, microorganisms and industry, biofilms: growth on submerged surfaces. Industrial microbiology: massive growth of naturally-occurring microbes to make low-cost products: biotechnology: genetically engineered microbes making high- value products in small amounts, production of biofuels, methane, ethanol, wastewater treatment, bioremediation: cleaning up pollutants. Light microscopy and the discovery of microorganisms: microbiology began with the microscope, robert hooke (1635-1703): first to describe microbes (micrographia in 1665)
