Microbiology Flashcards
What are the 5 main types of microbes?
- Bacteria
- Fungi
- Helminths
- Protozoa
- Viruses
Give a characteristic and 2 examples of bacteria
- Extracellular
- Coccus, Bacillus
Give a characteristic and 2 examples of fungi
- Cutaneous tissue and deep organs
- Yeast, Mushrooms
Give a characteristic and 2 examples of helminths
- Inflammation
- Nematode, Cestode
Give a characteristic and 2 examples of protozoa
- Mucosal damage
- Flagellates, Ciliates
Give a characteristic and 2 examples of viruses
- Intracellular
- Influenza, Measles
What is a Prokaryote?
A unicellular microorganism with no nucleus or membrane-bound organelles (e.g. bacteria)
What is a Eukaryote?
A multicellular microorganism with a nucleus and membrane-bound organelles (e.g. plants)
Which nucleic acids do bacteria, fungi, helminths and protozoa contain?
DNA and RNA
Which nucleic acids do viruses contain?
DNA OR RNA
Which microorganisms have a nuclear membrane?
Fungi, Helminths and Protozoa
What is the cell wall of bacteria made of?
Peptidoglycan
What is the cell wall of fungi made of?
Chitin
Which microorganisms respond to antibiotics?
Bacteria and Protozoa
How do bacteria replicate/ reproduce?
Binary fission
How do fungi replicate/ reproduce?
Binary fission and sexual reproduction
How do helminths replicate/ reproduce?
Sexual reproduction
How do protozoa replicate/ reproduce?
Binary fission and sexual reproduction
How do viruses replicate/ reproduce?
Within a host cell
What is a probiotic? Give 3 examples
A ‘friendly’ microbe (e.g. staphylococcus, E.coli, yeast)
What is a pathogen?
A disease-causing microorganism
Describe the process of microbial invasion
- Entry
- Attachment
- Penetration/ Evasion of tissue
- Penetration/ Evasion of host
- Production of toxins
- Damage to cells
Name 4 portals of entry for microbial invasion
- Respiratory tract
- Gastrointestinal tract
- Conjunctiva
- Skin
Name 4 things that the microbes may have to penetrate to enter a cell
- Capsules
- Cell walls
- Enzymes
- Cytoskeletons
Name the 4 ways in which microbes cause damage to cells
- Direct damage
- Exotoxins
- Endotoxins
- Lysogenic Conversion
How does an exotoxin work?
- Toxins are released into the surroundings
- These are found in gram positive bacteria
How does an endotoxin work?
- Toxins are released when the cell is disrupted (e.g. cell wall breaks down)
- These are found in gram negative bacteria
What is lysogenic conversion?
A lysogenic phage causes a change in the bacterial phenotype to make it more effective as a pathogen
Name 3 ways of preventing microbial invasion
- Hygiene
- Sterilisation
- Preventing cross-contamination
Describe the process of viral invasion
- Virus attaches to the cell and penetrates the membrane
- The nucleic acid of the virus is injected into the cell
- The virus uses the DNA of the cell to replicate
- The viral DNA is then released in viral particles
What are the 3 shapes of bacteria?
- Coccus
- Bacillus
- Spirillum
What is gram positive bacteria?
- Has a thick layer of peptidoglycan
- Retains crystal violet stain in gram staining
- Example = streptococci
What is gram negative bacteria?
- Has a thin layer of peptidoglycan
- Retains red counterstain in gram staining
- Example = Neisseria meningitides
Describe the process of binary fission
- DNA replication
- Cell elongation
- Septum formation
- Completion of septum with formation of distinct walls
- Cell separation
What are the 4 phases in the life cycle of bacteria?
- Lag phase
- Exponential phase
- Stationary phase
- Death phase
What is the lag phase?
A period of adaptation and preparation for growth via intense metabolic activity
What is the exponential phase?
A period of reproduction in which cells divide at a constant rate
What is the stationary phase?
A period in which the birth rate is equal to the death rate and the population has reached its maximum size
What is the death phase?
A period in which the death rate is greater than the birth rate due to nutrients being used up
What is asepsis?
Absence of microorganisms
What is the study of viruses called?
Virology
What is the study of fungi called?
Mycology
What is the study of bacteria called?
Bacteriology
What is the study of protozoa called?
Protozoology
What does the word commensal mean?
A symbiotic relationship between 2 organisms
