Lecture 4 Microbes 1 Flashcards
Why care about microbes (5)
They make us sick or not sick (gut, train immune system, protect against pathogens)
They evolve for billions of years,
They are present everywhere
They are essential for all global nutrient cycles (C, N, P)
They are models for evolution
Louis Pasteur proved that (microbes)
invisible microbes are responsible for fermentation, sepsis and disease.
Koch’s Postulates (to define infectious microbes) (4)
Found in abundance in all organisms with disease, none in healthy individuals.
Isolated from diseased and grown in pure culture
Cause disease when introduced to healthy organism
Identical to the original after infection
Symbiosis is
organism living together
Microbiome is
microbes living in and on plants/animals
Human have __% bacteria by mass, __ common species.
2%; 100
An example of mutually beneficial relationship
Vibrio fischeri on squid provide camouflage
An example of pathogenesis
vibrio cholerae causes diarrheal illness
Balance between bacterial and human cells: : by cells, : by genes
1:1; 100:1
An example of bacterial fossils studies that is living today
Stromatolites are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral “microbial mats”. In turn, these mats build up layer by layer, growing gradually over time. A stromatolite may grow to a meter or more.
Cyanobacteria through oxygenic photosynthesis can oxidize what
ferrous iron (2+) to ferric iron (3+) in flint and iron oxide
Characteristics of bacteria evolution (2)
infinite adaptation (no fitness plateau), very rapid
3 levels of biological organisation, their mechanism, and major processes
Boundary for cells and its function (1+3)
plasma membrane of phospholipid bilayer (use: transport, signals, adhesion)
Dual system of cells
Metabolism: harvest energy to form biomass
Information: store info to synthesize
Importance of cell membrane in terms of dual system
Without a membrane the products of metabolism would rapidly diffuse away from one another.
Without a membrane the information system could not be permanently linked to the metabolic system.
Why are large cells inefficient
SA/V is small. So cell reproduction happens instead of infinite growth.
Two steps of evolution of natural selection
Reproduction includes division of biomass and replication of info
Efficient metabolism leads to rapid growth and production, and is inheritable
Bacterial genomes store info in which two structures
nucleoid, plasmids (small DNA molecules not essential for function)
Three characteristics of plasmids in cell reproduction (3)
Numbers received may vary in daughter cells
Plasmids encode conjugation results in transfer to a recipient via a pilus.
Could benefit bacteria or be parasites.
Common process for eukaryotes and prokaryotes DNA replication? (7)
There are some occasional errors
The process of chromosome replication and cell division (6)
Differential reproduction leads to evolution by natural selection.
What does trophic links between different metabolisms of organisms mean
Product of one is reactant of another
