Microbiology l Flashcards
(20 cards)
What is a pathogen? What are some examples?
A disease causing microorganism. Examples include: bacteria, virus, fungi, yeast, protozoa
What does the term ‘acellular’ mean? What does it mean in relation to the term ‘cellular’?
An acellular organism contains no cells - it has a single complex cell, whilst cellular organisms contain many cells
Pathogenic microbial world - What type of pathogen is classified as an ‘acellular’ pathogen?
A virus
What is a microbe?
A tiny living organism that is too small to be seen with the naked eye**
Pathogenic microbial world - What type of pathogens are classified as ‘cellular’ pathogens that fit under prokaryotic cells?
Bacteria + Archea
Pathogenic microbial world - What type of pathogens are classified as ‘cellular’ pathogens that fit under eukaryotic cells’ category?
Yeast + Protozoa
Pathogenic microbial world (extra information) - What is a prion?
A specific type of protein that can trigger normal proteins to fold abnormally. for EXAMPLE:
- PrPc is a normal protein found in cell membranes (c = cellular)
- PrPsc infectious/atypical form of protein (sc = scrapie)
- PrPsc causes the PrPc to change its conformation to an abnormal form, they then convert more molecules, and a chain reaction occurs. They form an amyloid that accumulates and is deposited locally in the neural tissues.
What are the most common prion related diseases?
- Creutzfeld-Jakob disease (CJD), variant CJD (Mad cow disease) are most common diseases associated with prions
- Prions = Still largely unknown pathogen
Eukaryote Vs Prokaryote - What are the main differences between these two cell types?
EUKARYOTIC:
- Uni or multicellular
- Slow growth
- 5-20μm across (micrometres)
- Nucleus
- Nucleoli
- Histone associated DNA (*Histone= basic protein used in organising and packaging DNA)
- Membrane bound organelles
- Ribsomes 80s
- Cell membrane
PROKARYOTIC:
- Unicellular
- Rapid growth
- 0.5-3μm across (micrometres)
- Nuclear region
- NO nucleolus
- NO DNA associated protein
- No membrane bound organelles
- Ribosomes 70s
- Have a cell wall containing muramic acid
- Cell membrane
Cellular - Prokaryotic
What is bacteria?
A unicellular organism that has some form of cellular respiration to produce energy
Cellular - Prokaryotic
What different forms can bacteria come in?
A number of different shapes and anatomical variations, such as wall structures.
Cellular - Prokaryotic (Bacteria)
What is IMPORTANT to note about bacteria for paramedic students specifically - ***
?
That the identification of the nature of the pathogen links into the treatment required to overcome the infection
Cellular - Prokaryotic (Bacteria)
What do the terms gram negative and gram positive refer to?***
This refers to two broad categories of bacteria, based on how they react to a special lab staining technique called the Gram stain. This reaction reflects differences in their cell wall structure, which affects how they interact with dyes, antibiotics, and the immune system.
Cellular - Prokaryotic (Bacteria)
What colour does a gram negative bacteria stain?
Red
Cellular - Prokaryotic (Bacteria)
What colour does a gram positive bacteria stain?
Blue
What causes the differences in the results of the gram stain test? **
Gram-positive bacteria
Color after stain: Purple
Why: They retain the crystal violet dye even after the alcohol wash.
Cell wall structure: Thick peptidoglycan layer (a rigid mesh of sugars and amino acids)
- No outer membrane
Antibiotic sensitivity:
Often more sensitive to antibiotics like penicillin, which target the cell wall.
🔴 Gram-negative bacteria
Color after stain: Pink or red
Why: They lose the purple dye during the alcohol wash and take up the red counterstain.
Cell wall structure:
Thin peptidoglycan layer
Surrounded by an outer membrane with lipopolysaccharides (LPS) — toxic to humans
Antibiotic sensitivity: Often more resistant due to the outer membrane acting as a barrier.
What is the basic structure of gram positive bacteria?
Gram-Positive Bacteria
- Thick peptidoglycan layer (outermost)
- No outer membrane
- No lipopolysaccharides (LPS)
- Stains purple in Gram stain
Both have inner cytoplasmic membrane
What is the basic structure of gram negative bacteria?
Gram-Negative Bacteria
-Thin peptidoglycan layer (in the middle)
- Has an outer membrane
- Outer membrane contains lipopolysaccharides (LPS) (toxic to humans)
- Stains pink/red in Gram stain
Both have inner cytoplasmic membrane
What does gram-negative bacteria release?
Endotoxins
