Microbiology

Question 1

Describe protozoa

Answer 1

single celled animals, eukaryotes

Question 2

Describe fungi

Answer 2

higher plant like organisms, eukaryotes

Question 3

Describe bacteria

Answer 3

generally small, single celled prokaryotes

Question 4

Describe viruses?

Answer 4

very small obligate parasites, non-living

Question 5

Describe fungi and protozoa?

Answer 5

• 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)

Question 6

Describe bacteria?

Answer 6

•  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

Question 7

Describe a nucleoid?

Answer 7

Contains DNA and protein

No nuclear membrane

Chromosomes single circular molecule

Primitive DNA segregation

Question 8

How does DNA replication occur in nucleoids?

Answer 8

DNA replication via DNA dependent RNA polymerase, transcription & translation coordinated

Question 9

How are chromosomes organised in nucleoids?

Answer 9

– Organised by gyrases
– Extra chromosomal replicons
often exist i.e. plasmids

Question 10

What is the cell wall made up of in gram +ve and negatives?

Answer 10

• Rigid layer
• Barrier
• Repeated Polysaccharide structure

Question 11

What is unique to the structure of gram +ves?

Answer 11

• Gram +ve
– Thick multi-layer PG
• Target of Penicillin

Question 12

What is unique to the structure of gram ives?

Answer 12

• Gram –ve
– Outer membrane – Periplasm
– Thinner PG layer
• Target of Penicillin

Question 13

What is the role of lipopolysaccharides?

Answer 13

Structural role

Antigen & Bacterial Toxin-

Question 14

What are fimbriae?

Answer 14

• Gm +ve Fimbriae

– non-flagella protein appendages

Question 15

What is a pilus?

Answer 15

Gm -ve Pilus

– no motor, Pilin repeated protein unit