ID 1 Flashcards
What is ecology
Relationship with surroundings
What is physiology?
How something functions
What are the 2 types of prokarytoes?
Bacteria
Archaea (extremophiles, more like eukaryotes)
How many species of bacteria are there? How many cause disease?
200 million
2 thousand
What are Cyanobacteria?
Photosynthetic type of bacteria
What is a strain?
A genetic variant of a species
What is a commensal organism?
Organism which lives off another’s food/nutrients, but has no affect on the other
Like mutualistic relationship but only one organism benefits
How do bacteria communicate?
Quorum sensing
Bacteria detect and produce small molecules which enable them to determine the number of cells present
Describe the Ballicus genus
Gram positive
Aerobic
Spore forming
Can be extremophiles
What are 3 species of ballicus and what do they cause?
B. Anthracis - anthrax (lungs/skin/intestines)
B. Cereus - gastroenteritis
B. Thuringienesis - attack insect larvae
What are spores?
Unit of sexual/asesual reproduction
Adapted to help dispersal and survival in unfavourable conditions
What is a bacteriophage?
A virus that infects bacteria and archaea
What are the 2 types of viral replication?
Lytic cycle
Lytogenic cycle
What is the function of normal flora? How can they sometimes be harmful?
Prevent overgrowth of some bacteria and pathogens
React with sugar in diet to produce excess acid and damage teeth
What is virulence?
The degree of damage caused by a microbe to its host
What are the 4 growth phases for bacteria and what happens at each?
- Lag phase - after inoculation/vaccine
- Exponential growth - binary fission
- Stationary phase - nutrients deplete and waste products accumulate
- Decline phase - old then young bacteria die
What are 4 methods for bacterial enumeration? (establishing the number of)
Microscopic counting grid
Colony counting
Turbidity (cloudiness of fluid)
Opacity (non transparent areas)
What do bacteria require to grow?
Carbon
Nitrogen
Minerals
What are they 2 types of feeders and which is most common?
Autotroph - synthesise own food
Heterotroph - feed off organic compounds of others, most common
What are the 3 temperature classes that bacteria can be sorted into?
Psychrophilic - 15
Mesophilic - 20-45
Thermophilic - 60
What are the types of bacteria based on oxygen requirements?
Aerobes
Anaerobes
Microaerobes
What are the subtypes of anaerobes?
Obligate - killed by O2
Aerotolerant - not killed but don’t use it
Facultative - can grow with or without
What are the 3 ways bacteria respond to deficiency
Extracelluar molecules collect nutrients
Semi-starvation phase - smaller, slower met rate
Sporulation and resting cells
What are the types of culture mediums?
Defined (known composition)
Complex (exact unknown composition)
Differential (differentiate between microbes)
Selective (limit other microbe growth)
Why might microorganisms be preserved?
Vaccination
Testing
Research
How are bacteria preserved?
Liquid nitrogen
Freezing
What is a disinfectant?
Used to kill microbes on an inanimate object
What is a antiseptic?
Used to kill microbes on living tissue
What is a bacteriostatic?
Inhibits binary fission
What are physical methods of bacterial inactivation? (Damage/slow enzymes, proteins, nucleic acids and membranes)
Freezing
Boiling ( moist, autoclave, 121.5 for 15, dry flame)
Refrigerate
Vacuum (aerobes only)
Pasteurisation (flash or UHT for 1 second)
Why is gamma/ionising radiation not used for inactivation with humans? Why not UV?
Carcinogenic
Damages skin
What are chemical methods of inactivation
Sulfur dioxide Alcohol (not endospores or naked viruses) Increase osmotic pressure Halogens Phenols Metals
What are naked viruses?
Viruses with no envelope
What are most resistant to inactivation?
Spores
Prions
How does bacterial DNA replicate?
Semi conservative replication
5’-3’
By DNA polymerase
Describe the structure of a bacterial genome?
A single, circular
What is the difference between eukaryotic and prokaryotic protein synthesis?
Eukaryotic takes place in ribosomes and cytoplasm, prokaryotic just in ribosomes so translation/scription almost simultaneous
No intron removal in prokaryotic
What are examples of bacterial molecules?
Chromosomes Ribosomal rna Cell surface proteins Toxins Virulence factors
What is needed for PCR?
Genomic DNA
Polymerase
Primer (short sequence of nucleic acid)
Buffer
Describe the process of PCR?
Mix heated to 90 degrees to seperate DNA strands
Cooled to 30 degrees to allow primers to anneal
Heat to 60/70 degrees to join new strands
Repeat
What is DNA sequencing?
Determining the order of nucleotides in DNA
What are the 2 methods for DNA sequencing?
Maxam Gilbert - enzyme cleavage after certain base, radioactive, uses x ray
Sanger - chain termination after certain base, easy but requires PCR, no longer used for whole genomes
What is genetic typing or genotyping?
Comparing differences in 2 individuals genotype
