Mod 1 Flashcards
What is a microorganism?
It’s a single-celled organism.
What are other names for microorganism?
Microbe, bug, germ
What are the four groups of microorganisms?
- Protozoa
- Fungi
- Bacteria
- Viruses
How are microorganisms measured?
Micrometers (um)
What are protozoa?
They are unicellular creatures
How do Protozoa move?
They move by flagella or amoeboid motion
What is a feature of the nucleus in Protozoa?
Their nucleus is enclosed in plasma membrane
Where do you typically find Protozoa?
They live in soil and water
Some live in our body
What is an example of a Protozoa?
Giardia - causes diarrhea
Describe amoeboid motion.
Crawling-like movement
This is done by the cells forming temp cytoplasmic projections (pseudopodia) at the front of the cell
What are fungi?
A non-photosynthetic plants
What are the two groups of fungi?
Yeast
Mold
What is yeast?
Unicellular, oval structures
How does yeast reproduce?
By budding
What is the most common yeast to cause disease in humans?
Candida
What does yeast cause?
Oral thrust, vaginal discharge, skin infections, pneumonia, death
What are molds?
Multicellular structures that form visible clumps
What’s the structure of mold?
Starts as long tubular shaped then produces spores
What colour are the spores?
Grey, green, blue, or black
What are the typical human infections caused by molds?
Skin infections
What are bacteria?
Tiny unicellular organisms
What are bacteria surrounded by?
Rigid cell wall
What is special about bacteria?
They don’t have an organized nucleus but can be undergo activities for growth and reproduction
What does it mean to be ubiquitous?
They can be found anywhere that has nutrients and moisture
What are viruses?
Simple structured organisms that are smaller than bacteria
Is it necessary for a virus to have a host?
Yes!
Why is it necessary for a virus to have a host?
Because they’re unable to grow and reproduce without a host cells.
What are examples of a “host”?
Animals, plants, humans and even bacteria
What are the shapes of bacteria?
- Cocci/coccus
- Rods/bacilli (bacillus)
- Spirilla (spirillum)
How do you determine if a bacteria is GRAM NEGATIVE?
If the bacteria is PINK to RED after being stained
How do you determine if a bacteria is GRAM POSITIVE?
If the bacteria is dark bluish-black
Why is determining the gram reaction of a bacteria important?
It will help to determine the effectiveness of certain antibiotics and disinfectants
What are bacterial endospores?
Special types of spores produced by bacterial cells
What are vegetative cells?
Bacterial cells that don’t contain endospores
What is sporulation?
The formation of endospores
When does sporulation occur?
When certain nutrients are depleted
List the steps of the process of sporulation.
- Copy genetic material and tiny amount of cytoplasm is enclosed by a layer of insulating material
- Structure is then covered with compact layers of spore coat
- “Viable” endospores germinate into vegetative cells
What determines a viable endospores?
When moisture and nutrients are available.
What are the characteristics of endospores?
- can remain dormant
- resistant to heat
- More resistant to disinfectants
- very resistant to the cold
- resistant to UV light, acids: alkalis and detergents
How do bacteria reproduce?
Process of binary fission
What is the germination time?
The time it takes for the population to double
What’s the average gen time for rapid growing bacteria?
15-30 minutes
Generation time relates to the rate at which bacteria cause disease. (T/F)
True
What is a colony?
Mass of visible bacteria
*descendants of a single bacterial cell
What are the 4 growth phases for bacteria?
- Lag
- Log
- Stationary
- Death (decline)
Which phases defines the growth curve?
1-3
What is occurring in the lag phase?
When cells are placed in a new environment and takes time for the cells to adapt.
*little to no increase in # of cells
What is occurring at the log phase?
Period of MAXIMUM growth
*cells dividing at a constant rate
What is occurring at stationary phase?
When nutrient supply depletes and cells stop dividing
What also occurs to cause the stationary phase?
When the waste of the bacteria cells become too much
Key importance in stationary phase in regards to # of cells?
The number of live bacteria stay constant
What is occurring in the death phase?
Cells start to die and the ones that survive the longest are the ones that form spores
In relation to infection, what is happening at the LAG phase?
Incubation, no symptoms
In relation to infection, what is happening at the LOG phase?
Full-blown symptoms, Acute stage
What stage is crucial for the patients survival to have medical/or good immune defence at?
LOG phase
In relation to infection, what is happening at the STATIONARY phase?
Symptoms not worse but no sign of recovery
In relation to infection, what is happening at the DEATH phase?
Symptoms subside
What does convalescence mean?
Time needed to completely recover
What are the key characteristics of viruses?
- need to have a host cell in order to reproduce
- either have DNA or RNA, not both
- some viruses have envelopes that are made of lipids, some have spikes from the lipid envelope
Lipid viruses are harder to inactive with disinfectants. (T/F)
False
What surrounds the nucleic acid in viruses?
Protein coats
What are the four steps to virus multiplication?
- Virus attached to complementary receptor sites
- Virus is taken in by endocytosis
- Cell digest the protein coat which releases the nucleic acid
- Viral nucleic acid synthesis proteins which joins DNA in the nucleus and moves out of the cell
What are the effects of the virus to a host cell?
- lysis of cell
- diversion of the cells metabolic pathways
- sometimes the host will destroy the cell that has the virus, but the cell might be crucial
- some viruses can alter the DNA of host cells to turn them into tumour cells
What are oncogenic viruses?
The ones that alter the DNA of host cells to turn them into malignant cells
