Microbiology Flashcards
What is a Protozoa?
Is it a eukaryote or a prokaryote?
Single called animal
eukaryotes
What is a virus?
Is it considered living in microbiology?
Very small obligate parasite
Considered non-living
What is an obligate parasite?
Parasite which cannot survive without host
Are bacteria eukaryotes or prokaryotes?
Prokaryotes
Are fungi eukaryotes or prokaryotes?
Eukaryotes
Describe the basic differences between a eukaryote and a prokaryote
Eukaryote Big Complex (with compartments) Mostly multicellular Linear chromosome (attached to histones) Introns and exons Flexible or no cell wall Mitosis/meiosis
Prokaryote small simple Mostly single celled Circular chromosome Few introns Rigid cell wall Fast cell cycle
What elements do all eukaryotic cells contain?
Cell membrane Nucleus and nucleolus Ribosomes Golgi apparatus Endoplasmic reticulum Mitochondria
What do all prokaryotic cells contain?
Cell envelope (wall)
Cell membrane
Ribosomes
DNA
What is a nucleoid?
Area in prokaryote containing DNA and proteins
No nuclear membrane
Describe the structure of chromosomes in a nucleoid
Single circular chromosome
Organised by gyrases
Extra plasmids may be present
Why is the membrane so important to bacteria?
Only barrier between them and world
Allows them to maintain ion gradient and membrane potential
What is the difference in cell wall between a gram positive and gram negative bacterium?
In gram positive the cell wall is made of the following layers:
Peptidoglycan (thick)
Proteins
In gram negative it is as follows:
Thin layer of peptidoglycan
Periplasm
Outer membrane
What does penicillin target?
Bacteria cell walls
What does LPS stand for?
Lipopolysaccharide
Where is LPS found and what does it do?
Found on outer membrane of gram negative bacteria
Prevents large hydrophobic molecules entering bacterium
Lipid A linked to toxicity
Linked to O-antigens
What is the difference between Fimbriae and Pili?
Fimbriae: Numerous Short Thin Flexible Involved in adhering cell to others Made from flagellin
Pili: Only a few per cell Long Thick Rigid (shape, length, and rigidity can change based on type of bacterium) Involved in conjugation
What is bacterial conjugation?
When bacteria share genetic information horizontally
Uses Pili
Where are fimbriae and pili found?
In both gram positive and negative bacteria
What proteins makes:
Fimbriae?
Pili?
Flagellum?
Fimbrillin
Pilin
Flagellin
What is a sex pilus?
Pilus involved in transference of genetic information (bacterial conjugation)
What in prokaryotes can be targetted by antibiotics?
Protein synthesis
What nutrients do prokaryotes need for growth?
Source of: Carbon (eg sugar, protein, or CO2) Oxygen Hydrogen Nitrogen (eg amino acid, ammonia) Inorganic salts (eg Mg, Ca, Fe, K, P, S) Trace elements (eg Zn, Cu, Mn, Ni, Mo) Vitamins (eg folic acid, niacin)
What conditions do prokaryotes need for growth?
Access to nutriens Appropriate temperature Appropriate pH (H+ conc) Osmotic protection Appropriate oxygen level
What is a Psycrophile?
Prokaryote which prefers low temperatures
