I&I Flashcards
Name the 4 groups into which microbes can be classified
Viruses
Bacteria
Fungi
Parasites
Name the 2 types of parasite
Protozoa and helminths
Name 5 properties of viruses
1) They have a DNA or RNA core within a protein capsid made of capsomeres.
2) They have a helical, cubic or more complex arrangement
3) They have no cytoplasm
4) They may have an envelope derived from the host cell
5) They have membrane-bound attachment proteins
What is meant by the phrase ‘viruses are obligate intracellular organisms’?
Viruses must invade cells in order to replicate inside the cell
Name 3 viral causes of upper respiratory tract infection
Rhinovirus, influenza and RSV
Name 2 viral causes of gastroenteritis
Norovirus (SRSV) and adenovirus
Name 2 viral causes of rashes
Varicella zoster virus and measles
Name the virus responsible for meningitis
Enterovirus
What’s a healthcare associated infection?
An infection commonly acquired in hospital
Name 10 properties of bacteria
1) Prokaryotic cells
2) Haploid DNA
3) No nucleus
4) Usually have a rigid cell wall outside the cytoplasmic membrane
5) Circular DNA
6) No histones
7) No introns
8) No mitochondria
9) No membrane-bound organelles
10) Reproduce by binary fission
What’s the difference between strict aerobes and facultative aerobes?
Strict aerobes can only grow in free oxygen. Facultative aerobes can also grow in the absence of oxygen
What are the 2 main morphologies of bacteria?
Cocci (spherical) and rods/ bacilli (cylindrical)
Describe gram stain and how it divides bacteria
Gram positive bacteria stains blue. Gram negative bacteria stains red
What are the 2 factors that determine whether bacteria is gram positive or gram negative, and which is which?
The thickness of the peptidoglycan layer, and the presence or absence of an outer lipid membrane. Gram positive bacteria have a thick peptidoglycan layer and have no outer lipid membrane. Gram negative bacteria have a thin peptidoglycan layer and have an outer lipid membrane.
What bacteria commonly causes a UTI?
Escherichia coli
What bacteria commonly causes pharyngitis?
Streptococcus pyogenes
What bacteria commonly causes skin and soft tissue infection?
Streptococcus aureus
What bacteria is commonly responsible for causing post-operative wound infection?
Staphylococcus aureus
What bacteria is commonly responsible for causing ventilator-associated pneumonia?
Pseudomonas aeruginosa
Name 6 properties of fungi
- Eukaryotic
- Haploid or diploid DNA
- Mono- or polynucleate
- Have a rigid chitinous wall outside the cytoplasm
- May be multicellular or single cell or filamentous form.
- May be dimorphous
How do teleomorphous fungi reproduce?
Sexually
How do anamorphous fungi reproduce?
Asexually
Name 5 properties of parasites
- Single celled
- Single or multiple nuclei
- Haploid DNA
- Morphology varies throughout their life cycle
- May have flagella
What are helminths?
Helminths are multicellular parasitic worms which can be microscopic or visible to the naked eye. A lot of helminths don’t cause harm to humans.