Microbes Flashcards
Learn vocabulary and concepts associated with microbes
LUCA
Last universal common ancestor
Eocyte Tree
Proposed eukaryotes as a branch of archaea
Ether linkage
Membrane lipids in archaeal phospholipids
Esther Linkage
Membrane lipids in bacterial phospholipids
Binary fission
Asexual prokaryote reproduction (vertical transmission) that gives rise to clones
Plasmid
Extra chromosomal DNA that is circular
Lateral Gene Transfer
Horizontal gene transfer between prokaryotes that can happen from farther distances
Conjugation
Plasmid or piece of chromosome transferred via sex pilus
Transformation
Outside portion of genome transferred via crossing over or recombination
Transduction
Takes host DNA to other cell via phage
Anaerobes
Bacteria/archaea that do not tolerate and may be killed by oxygen
Aerotolerants
Bacteria/archaea that tolerate but can’t use oxygen
Microaerophiles
Bacteria/archaea aerobes that can use oxygen only at reduced levels
Facultative
Bacteria/archaea that can live with or without oxygen but prefer oxygen
Aerobes
Bacteria/archaea that require oxygen to live
Gram positive
A dense cell wall that is more resistant
Gram negative
A thin cell wall
Photoautotrophs
Light; Co2
Plants
Photoheterotrophs
Light; Organic compound
Chemoheterotrophs
Chemical; Organic compound
Humans
Chemoautotrophs
Chemical; Co2
Extremophyles
An organism that can tolerate extreme environments
Great Plate Count Anomaly
Many microbes will appear on a plate but only few will culture successfully
Virus
Noncellular infectious agents that can only replicate inside living cells of organisms
What are the main components of a virus?
nuclein acid and a protein coat (aka capsid)
Virion
Extracellular form of a virus that contains a RNA/DNA genome
Capsid
A protein shell that encloses the genetic material
Nucleocapsid
Capsid + Nucleic Acid genome
Envelope
It allows viruses to go in and out of host cells through the cell membrane (fuse)
Eclipse phase
The time when a cell attaches to a host and begins virus production successfully
Maturation phase
Transition of a non-infectious to a infectious virion
Plaques
A circular clearing in a lawn of bacteria growing on the surface of a nutrient agar gel
Lytic
Virus life cycle that involves the destruction of the host and replicates independent of host
Lysogenic
Virus life cycle where viral DNA is incorporated into host cell chromosome and replicated with host DNA
Mutualism
+/+ : Both organisms benefit
Commensalism
+/0 : One organism benefits and the other has no effect
Parasitism
+/- : One organism benefits at the other organism’s expense
Parasite
An organism living in or on another organisms at the expense of that organism
Pathogen
A biological agent that causes disease/sickness to host
Infectious disease
A disease that is caused by a pathogen which can spread from diseased to healthy host
Non-infectious disease
A disease that is caused by environmental factors/genetics and can’t be passed
Zoonotic disease
A disease transfer from animal to human
(Genetic reassortment)
How much of the tree of life is microbial?
Almost all! excluding eukaryotes
Why was the rRNA selected for reconstructing phylogeny?
rRNA is highly conserved between different species of bacteria and archaea and everybody has it (consistent)
Why have microbes been difficult to place on the tree of life historically?
There is no fossil record
Microsporidiutum characteristics (no mitochondria)
How did Carl Woese arrive at the three domains tree?
He used the data he sequenced from rRNA
How is the eocyte tree different from the three domains tree?
It shows eukaryotes branching off from archaea rather than being their own branch
What are the major differences between prokaryotes and eukaryotes?
Nucleus and Membrane bound organelles
What are the differences between bacteria and archaea?
Peptidoglycan presence
Esther vs Ether linkage
Why do microorganisms develop resistance to antibiotics?
Through mutation and rapid replication and selection
How is binary fission different from mitosis?
It is simpler and faster and environmental influence. It is also by means of asexual reproduction
How is genetic variation introduced during binary fission?
A plasmid and mutation
What are the similarities and differences between LGT and sexual reproduction in eukaryotes?
SIMILARITIES: both create genetic combinations; recombination
DIFFERENCES: LGT only part of genome, can occur over large distances, not linked to reproduction, and has multiple possible mechanisms
How can genetic variation be introduced in microorganisms?
Mutations and LGT recombination
What are the three possible methods for LGT?
Conjugation, Transformation, and Transduction
What are some examples of traits introduced by LGT?
Anitbiotic resistance and virulence attributes and metabolic properties
What is the impact of LGT on phylogeny reconstruction?
May cause confusion of how traits appear (complicate)
How do organisms obtain carbon and energy?
Bacteria and archaea are diverse in how they obtain
Eukaryotes are metabollically linked
How is LGT important for biotechnology?
Used in research labs to produce medicine
EX: insulin
How are microbes grouped according to the temperature?
Psychrophiles-Hyperthermophiles
(cold-hot)
Why is it that so many microbes can’t be cultivated?
It is hard to replicate the numerous different and complex environments they need to survive
How does the Gram stain work?
It involved the ability of the cell wall to retain violet dye during treatment. It determines the thickness based on peptidoglycan content and lipid content
How are plant viruses able to infect a plant?
Either by an open wound or via an insect
What is the replication cycle of a virus?
- Attachment
- Penetration
- Replication (DNA and protein synthesis)
- Self Assembly
- Exit and re-locate
Why are viruses important for ecosystem function?
Carbon and nitrogen systems and marine ecosystems to circulate
What are the sources of human diseases?
bacteria, viruses, parasites
Host jumps and Zoonotic
How do you get inoculated with microorganisms when you are born?
Microbes from mother in numerous ways (breast, milk, vagina, uterus)
Why are microbiomes of various body parts so similar between individuals?
They perform specific functional capabilities and have certain purposes within those areas
What are benefits of carrying your gut microbiome?
The gut microbiome has several health benefits relating to weight, immune system, and metabolism
