Introduction to microbiology Flashcards
Would you expect to find microorganisms in the skin of a healthy person?
Yes
Would you expect to find microorganisms in the blood of a healthy person?
No
Would you expect to find microorganisms in the mouth of a healthy person?
Yes
Would you expect to find microorganisms in the stomach of a healthy person?
Yes
Would you expect to find microorganisms in the colon of a healthy person?
Yes
Would you expect to find microorganisms in the cerebrospinal fluid of a healthy person?
No
Would you expect to find microorganisms in the joint fluid of a healthy person?
No
Which areas are densely populated with normal flora?
Large intestine
Mouth
Female reproductive tract
Upper respiratory tract
Which areas are moderately populated with normal flora?
Skin
Stomach
Urethra
Which areas have a low amount of normal flora?
Lower respiratory tract
Bladder
Which areas have no normal flora?
Blood
Tissue
Joint fluid
CSF
Where is staphylococcus spp found?
Skin
Where is streptococcus spp found?
Mouth, nose and throat
Name two bacteria found in the GI tract
Bacteroides spp
Escherichia coli
What type of bacterium is escherichia coli?
Coliform
What are facultative microbes?
Can use electron donors
Why is normal flora important?
Protect from pathogen colonisation (no space for pathogens)
Develop immune system
What diseases can streptococcus pneumonia cause?
Pneumonia and meningitis
What are the main groups of microorganisms and what are their sizes?
Bacteria (1 micrometer)
Parasites (protozoa are less than 5 micrometers and metazoan are cm)
Fungi (less than 5 micrometers)
Viruses (less than 0.2 micrometers)
What ribosomes are found on a bacteria cell?
70s - has 30s and 50s subunits
How long is a bacterium?
1 micrometer
What are the pili used for?
Attachment
What are flagella used for?
Movement
What are the three shapes of bacteria?
Spheres, rods and spirals
What is the cell wall made from?
Peptidoglycan and lipopolysaccharides
What does the gram stain do?
Divides bacteria into two groups depending on cell wall and size
How do you do a gram stain?
Add a stain and bone to peptidoglycan
fix it
Add alcohol - if there is a little stain it can be stripped away
Add counter stain
Should be categorised into gram positive and gram negative
What is the dormant state of a bacteria spore?
Resistant to heat/drying/alcohol/UV
Returns to vegetative state when conditions favourable
What are the two types of eukaryotic cell?
Yeast and mould
What is a cutaneous bacterium?
Direct contact, common athletes foot
What is a subcutaneous bacterium?
Puncture wounds/trauma
What is a systemic bacterium?
Inhaled and then spread
What is an opportunistic bacterium?
Immuno-compromised, rare but serious
Characteristics of protozoa and metazoa
DNA in nucleus Organelles Cell wall and membrane Can have outer walls Metabolic processes close to human ones
How do amoebae move?
Phagocytosis
How do flagellates move?
Flagella
How do sporozoa move?
Picked up by host
How are protozoa classified?
How they move
How are metazoan classified?
Shape
What shapes can metazoa have?
Round worms, tape worms, flukes
Examples of viruses
Herpes
Chicken pox
Shingles
Characteristics of viruses
Can only replicate after invading host cell
Nucleic acid (can be RNA/DNA and single/double stranded)
Nucleocapsid
Viral proteins inserted into host cell
0.2 micrometres
How do viruses replicate?
Attaches to host Endocytosed into cell Unwraps itself Replicates nucleic acid and proteins Can leave cell by budding out
What shapes can it have?
Helical
Icosahedral
Complex
