Microbiology Flashcards
What does a prokaryote consist of?
Nucleoid
Ribosomes
Cell membrane
Flagellum
Capsule ( in some )
What does the cell wall do?
Holds the cell together
What does penicillin do to a cell?
Bursts cell wall and prevents construction of cell wall in new cells
What is a glycocalyx/capsule?
Adhering layer around bacteria that acts as a barrier against drying and phagocytosis
If thick called capsule
If thin called slime layer
What are the fimbria?
Small hairlike appendages that aids adhesion to a host and transfer of genetic material.
Also known as pili
What are flagella?
Hairlike appendages that allow bacteria to move
They are larger than pili
What is cytoplasm?
Fluid within the cytoplasmic membrane
Contains dissolved nutrients, ribosomes and energy stores
What are plasmids?
Separate closed loop of DNA inside bacteria that stores information regarding toxicity and drug resistance
What is the structure of bacteria?
Nuclear material
Flagella
Capsule
Fimbriae
Cell wall
Plasmid
Cytoplasm
Cytoplasmic membrane
What are spores?
Genetic material that is freed on death of a bacterial cell. Highly resistant, anthrax is a common spore bacteria.
What is generation time in bacteria?
The time it takes for cells to divide. This helps determine the incubation period in healthy people before symptoms appear.
What 4 stages are in the bacterial growth curve?
Lag phase
Exponential phase
Stationary phase
Death phase
What is the lag phase in the bacterial growth curve?
First few hours of bacteria adapting to the new environment.
The bacteria population remains balanced as reproduction = death rate
What is the exponential growth/logarithmic phase in the bacterial growth curve?
Reproduction stage, bacteria grows and spreads,
Symptoms begin to show
Also known as exponential growth phase
What is the stationary phase of the bacterial growth curve?
Vigour of population changes
Reproduction rage equals death
Antibodies and white blood cells attack bacteria.
Nutrients become scarce, waste accumulates, oxygen and water are in short supply
Bacteria also have less oxygen and water and more waste to contend with.
What is the decline phase of the bacterial growth curve?
Population begins to die off.
May take longer if bacteria is spore forming.
Disease ends normally ends with death of last cell
Also called exponential death phase
There are 3 types of bacteria that enjoy different temperature ranges. Mesophile bacteria thrive at 20 to 40 degrees which makes them ideally suited to what?
The human body
What is the pH of most bacteria.
7, most thrive in neutral environments
What are the two broad groups of fungi?
Yeast and moulds
How are protozoa different from bacteria?
They have a nucleus and organelles
Are much more mobile
What is the structure of a bacterial cell?
DNA / Nucleoid
Cytoplasm
Plasmid
Cytoplasmic membrane
Cell wall
Capsule
Fimbriae
What is the cell wall of bacteria?
A non living protective layer around the cell that protects it and enhances survival
It determines its shape and holds everything together
Pencilling prevents construction of the walk in new cells and they burst quickly
What is the cytoplasmic membrane in bacteria?
The boundary layer between the bacteria and it’s environment
It is a semi-permeable membrane that allows the passage of nutrients and waste
What is the nuclear material of bacteria?
DNA coiled as a single strand. There is no membrane around the DNA.
What is the cytoplasm of a bacteria cell?
A fluid contained within the cytoplasmic membrane that contains dissolved nutrients, ribosomes and energy stores
It is the foundation substance of the cell
What are plasmids in a bacterial cell?
Extra-chromosomal genetic structure
Can replicate within the cell independently
Composed of DNA in a circular structure
Carries information about antibiotic resistance and toxin production
