Intro to microbiology Flashcards
How long ago was the world formed
4.5 billion years
What are stomatolites
Sediments alternating layers of limestone and bacterial communities called microbial mats
When was the atmosphere and water formed
4 billion years ago
How old are the oldest sedimentary rocks
3.9 billion yeas
How old are stromatolites
3.5 billion years
What are the 4 theories to the origin of life
Prebiotic soup - chemical theory
RNA world
Apparition of cellular life
Panspermia
What is the prebiotic soup model
Formation of amino acids from simple chemicals under conditions mimicking Earths primitive conditions
What is the problem with the prebiotic soup model
The experiment requires a reducing atmosphere which requires high H2 concentrations
No AA in sediments
Why is RNA theorised to be the oldest macromolecule encoding complex information
Only 4 building blocks instead of 20 for proteins
Requires less energy than DNA to form
Contains Uracil which is formed early in biochemical pathways
ssRNA can be used as genetic material
RNA can have catalytic activities - Ribozymes
What do ribozymes do
Cleavage/ligation
Replication
Formation of peptide bonds
What component is key to compartmentalisation
Phospholipids
Why use compartmentalisation
Protection from environment
Selective barrier
Concentration of molecules for metabolism
How would apparition lead to life
AA and RNA would have been trapped leading to the first primitive cellular form of life.
What makes microbes diverse
The haploid genome
Why bacteria so good at mutating
High diversion rate
Most only have one chromosome so only need one mutation
What are the three types of horizontal gene transfer
Transformation
Transduction
Conjugation
What is horizontal gene transfer
The non-sexual movement of genetic information between genomes
What is transformation in HGT
Bacteria take up DNA from their envioroment
What is transduction in HGT
Bacteria directly transfers genes to other cells
What is conjugation in HGT
a transfer of DNA from a living donor bacterium to a living recipient bacterium by cell-to-cell contact
What is taxonomy
Classification of organisms
What is an arthropoda
Segmented animals with hard skeletons
What are 4 ways to identify and classify microbes geneotypic analysis
DNA hibridisation - 2 species and comparing how similar they are by how much DNA can re-anneal
Flourescence in Situ Hybridisation - Specific gene is labelled and hybridised in DNA sample to see which organisms have the gene of interest
Whole genome sequencing (labrats)
Multi locus sequence typing - MLST picks housekeeper genes ( present in most organisms), sequences them and gives the barcodes, compare the barcodes
What is phylogeny
Study of evolutionary history of organisms
Uses molecular clocks
What are the 3 domains defined by carl WOese
Archea, bacteria, eukarya
What are the phenotypic analyses
Morphology - Looks at shape
Pure Isolates:
metabolic properties - Value of postive test is circled and number given to the ID value
Phage typing - Grow bacteria in agar and spot the different phages which target organims
, Fatty acid profiles - Take bacteria culture and extract fatty acid
Mass spectrometry - Extract surface protein from organism to establish fingerprint and compare to database
What are molecular clocks
a method used to estimate the amount of time needed for a certain amount of evolutionary change
Encoding conserved proteins with similar functions, undergoing random and neutral mutations
Difference between taxonomy and phylogeny
Taxonomy is the science/study of classification. Phylogeny is the science/study of evolutionary relationships between organisms
What process does phylogeny study
Evolution
What does taxonomy study
Classification of organsims
What is the order of the kingdoms
Domain/Kingdom/Phylum/Class/Order/Family/Genus/Species
What phenotypic analysis studies bacterial morphology
Differential staining
What is used during mass spec to identify bacteria
An isolate of whole bacteria
Difference between eukaryotes and prokaryotes
Eukaryotes are bigger than prokaryotes with bigger volumes
Eukaryotes have a nucleus prokaryotes dont
Membrane bound organelles in eukaryotes
What is the nucleus
Contains chromatin (DNA and histones), site of transcription (rRNA, tRNA and mRNA)
What does the RER do?
Active site of protein synthesis, translocation into RER for secretion
What does the SER do?
Lipid and steroid synthesis
What does the golgi complex do?
Carbohydrate synthesis, proteins transport in vesicles, post-translation modifications
What does lysosomes/peroxisomes do
Digestion of macromolecules and organelles
Alcohol and fatty acids metabolism - peroxisomes
What does mitochondria do
ATP synthesis and reducing power
What does chloroplasts do
Converts light into organic compounds via calvin cycle
What does flagella do?
Made of microtubules
ATP hydrolysis - driven
Whip like movement
What does nucleoid do
Highly compacted chromosome in complex with proteins
This region regulates the growth, reproduction, and function of the prokaryotic cell
What does cytoplasm
Site of protein synthesis
Contains protein - bound inclusion bodies
What does the cell envelope contain
Cytoplasm and peptidoglycan and sometimes outermembrane.
Presence of additional polymers
What are apendages
Pilus (conjugation) fimbria (Adhesion to eukaryotic cells) or flagella (Mobillity)
Flagella rotate
What is the endosymbiotic origin of eukaryotes
Stable incorporation of endosymbiotic bacteria resulted in the formation of mitochondria and chloroplasts
What is the problem with the endosymbiotic theory
Doesnt account for the fact that both eukaryotes and prokaryotes have similar lipid composition
What way does the Cis face of the golgi complex face
ER
What are magnetosomes
Trap metal compounds to create a magnetic field
What ribosomes do eukaryotes have
Prokaryotes
80s
70s
How cellular are fungi?
Unicellular and MULTI MULTI M
What is the role of fungi in the environment
Contribution to the carbon cycle
Decomposers
What is penicillin
A mould
What are fungi cell walls made of
Chitin
How do chloroplasts divide
Binary fission
Do chloroplasts have their own genome
Yes
What process does the nucleus do
Active site for transcription
What does the Golgi do
Modify proteins so they can target membranes
What do mitochondria generate
ATP
Do mitochondria and chloroplasts have their own genome
Yes but contain proteins encoded by the nuclear genome
Where are histones found
Eukaryotic cells
How is flagella motion driven
ATP hyrolysis
what is the lifecycle of a fungi
2 phases involving asexual and sexual reproduction to form spores
Transition between unicellular and multicellular forms
what is the lifecycle of mould
Alternating haploid/diploid phases
What are the 4 major groups of unicellular eukaryotes
YEAST, Algae, Protozoa, Slime molds and amoebas
Hi Aidan, have you brushed your teeth?
What properties do fungi have in common
Morphology - most form multicellular filaments and are pleiomorphic (hyphae)
Cell wall - made of carbohydrates
Life cycle
What is the life cycle of a yeast
Cell division via budding/binary fission
Haploid –> mating –> cell fusion –> nuclear fusion –> diploid
Diploid –> meiosis –> Germination –> haploid
Name a model unicellular algae and explain its key properties
Chlamydomonas reinhardtii
Huge chlorplast with 2 membranes
Pyrenoid to stock bicorbonate to be converted into CO2
Contracile vaciole for osmoregulation
Cell wall made of hydroyproline-rich glycoproteins
Describe the unique properties of diatoms
Mobile but no appendages
Used as an abrasive material in toothpaste
Complex chloroplast (4 membranes )
Mixotrophs (photosynthesis and metabolism)
Frustules as cell wall (silica)
Most ABUndance in phytoplankton
Hey karen
Where do moulds absorb nutrients
At the tip of the hyphae
What do ectomycorrihizal basidomyocytes do
Help trees and plants absorb minerals
Type of mushroom
Increase SA
What are the types of fungi
Molds - filamentous
Yeasts - Unicellular
Basidomycetes - mushrooms
Why are algae ecologially important
Produce half of atmospheres O2
Key food item in ocean food web and aquaculture
What are the key properties of algae
Photosntheic organisms
Have chloroplasts like plants but diatoms have a more diverse metabolism
What is the lifecycle of algae
Mostly found as haploid cells dividing by binary fission (asexual reproduction)
Haploid cells from opposite mating types can furse to form a zygote which loses the flagella and grwos a protective coat
Zygote undergoes meiosis to regenerate haploid cells
What is the cell wall of a diatom called
Frustule
What are the two types of diatom
Centric and pennate
Centric - radial symmetry
Pennate - Bilateral symmetry
What is the use of diatoms
Natural treatment against fleas and mites
What are frustules made of
opaline silica
Key role in carbon cycle
What are the 3 protists
Algae, Protozoa and SIime mould/ameobas
What are the key properties of alveolates
Contain alveoli
Motile organisms
Mostly aquatic
What are the three types of alveolates
Cilates - predatory protists
Apicomplexans - parasites
Dinoflagellates - predatory algae
What is the ecological importance of alveolates
Food web (zooplankton)
Apicomplexans (Malaria)
Dinoflagellates are key in carbon cycle
Where are alveoli found in ciliates
Under the cytoplasmic membrane
how do ciliates kill pray
Ingested and enclosed in phagocytic vacuole
What are apicomplexa
Spore-forming parasitic protozoans without flagella, cillia or pseudopods
Contain apicoplast which generated chloroplasts carrying out fatty acid metabolism
What is the life cycle of apicomplexa
The parasite uses a vector (mosquito)
The sporozoite is the infectious form
Multiply in schizont which rupture to release merozoites
Merozoites can differentiate into gametocytes
Gametes fuse to form a zygote
What are dinoflagellates
Photosynthetic aquatic organisms
Mixotrophs - use energy that are not light and Carbon
Responsible for algal bloom which can be toxic to fish and shellfish
Mobile predatory algae feeding on bacteria, algae ect
Involved in complex symbiotic or parasitic interactions
What is the structure of dinoflagellates
2 flagella (one wrpaped around cell
Chloroplast with complex membrane
Cell walls made of thecae
Contain an organelle called the extrusome
What is Mixotricha paradoxa
Found in gut of termites
Lives in symbiosis with bacteria
What is giardia lambia
Human parasite causing diarrhea
Contains 2 nuclei
Adhere to epithelial cells using adhesive disk
What is trypansoma brucie
Transmitted through fly
2 phases
Fever, headache, LN inflammation
Parasite invades CNS, disrupts sleep
Are slime molds a type of fungi
No
Can Algae be both multi and uni cellular
Yes
Can some protists carry out photosynthesis
YES
ALL GAE
Are most fungi unicellular
No
Can Fungi be pathogens
Yes
Are fungi always multicellular
No
What is the cell wall of fungi made of
Polysaccharides including chitin
Where is the hyphae found
Growing part of mycelium
What do all unicellular algae have in common
Carry out photsynthesis
Which model algae has 2 flagella
Chlamydomonas reinhardii
What is toxoplasma gondii
Parasite
How do slime molds move
Pseudopods
Do diatoms have a large range of morphologies
Yes
