Microbiology Flashcards
(15 cards)
Describe protozoa
single celled animals, eukaryotes
Describe fungi
higher plant like organisms, eukaryotes
Describe bacteria
generally small, single celled prokaryotes
Describe viruses?
very small obligate parasites, non-living
Describe fungi and protozoa?
- Size 5-50 mms
- Complex (Compartmental)
- Frequently multi-cellular
- Linear chromosome + Histones
- Introns/Exons
- 80S Ribosomes
- No/Flexible Cell Wall (sterols)
- Cell cycle (mitosis/meiosis)
Describe bacteria?
• Size 0.5-10 mms • Simple • Often single celled • Single Circular Chromosome • Gene structure (introns rare) • 70S Ribosomes Co-transcription/translation • Rigid Cell Walls (PG) • Rapid Cell cycle
Describe a nucleoid?
Contains DNA and protein
No nuclear membrane
Chromosomes single circular molecule
Primitive DNA segregation
How does DNA replication occur in nucleoids?
DNA replication via DNA dependent RNA polymerase, transcription & translation coordinated
How are chromosomes organised in nucleoids?
– Organised by gyrases
– Extra chromosomal replicons
often exist i.e. plasmids
What is the cell wall made up of in gram +ve and negatives?
- Rigid layer
- Barrier
- Repeated Polysaccharide structure
What is unique to the structure of gram +ves?
• Gram +ve
– Thick multi-layer PG
• Target of Penicillin
What is unique to the structure of gram ives?
• Gram –ve
– Outer membrane – Periplasm
– Thinner PG layer
• Target of Penicillin
What is the role of lipopolysaccharides?
Structural role
Antigen & Bacterial Toxin-
What are fimbriae?
• Gm +ve Fimbriae
– non-flagella protein appendages
What is a pilus?
Gm -ve Pilus
– no motor, Pilin repeated protein unit
