Types Of Microorganisms

Question 0

What are the defining characteristics of a prokaryotic cell?

Answer 0

• Absence of a true nucleus
• Generally 1 single chromosome
• Absence of complex cell organelles
• Photosynthetic pigments, if present, generally in lamellae

Question 1

Starting from the smallest name the types of Microorganisms?

Answer 1

• Virus
• Prokaryotes
• Eukaryotes
• Helminth

Question 2

Defining characteristics of a eukaryotic cell?

Answer 2

• Complex nucleus (bounded by nuclear membrane) and contains nuclei and some chromosomes
• Contain complex organelles such as mitochondria and chloroplasts
• Cell division involves mitosis

Question 3

Defining characteristics of archaea?

Answer 3

• Most primitive life form still in existence - most closely related to the first cells 4 billion years ago
• Occur in extreme environments similar to conditions on ancient earth
• Prokaryotic in general structure but possess unique characteristics
• Unique plasma membrane and cell wall composition
• May actually be more closely related to the eukarya domain than to bacteria

Question 4

Name some examples of archaea?

Answer 4

• Methanogens (anaerobic swamp mud, guts of animals, sea sediments)
• Extreme halophiles (salt lakes, salt mines)
• Psychrophiles (Arctic)
• Hyperthermophiles (volcanic springs eg Pyrococcus furiosus “the furious fireball”)

Question 5

Defining characteristics of bacteria?

Answer 5

• Single cells
• Arrangements of cells (clusters, chains)
• Do not have nucleus
• Variety of shapes
• Average size ~ 1-2 micrometers
• Reproduce by binary fission

Question 6

What is the significance of bacteria?

Answer 6

• Huge population in/on human body - skin, mouth and large intestine
• Natural population protects against infection, produces beneficial substances (eg vitamin K)
• Can cause diseases
• Can be genetically engineered to produce insulin, HGH etc

Question 7

Defining characteristics of a virus?

Answer 7

• Specific to host
• DNA or RNA surrounded by protein (and perhaps outer membrane)
• Only replicate in suitable host cell
• Cause numerous diseases

Question 8

What are viroids?

Answer 8

Fragments of nucleic acid (RNA) - responsible for some diseases in plants but none known in animals

Question 9

What are prions?

Answer 9

Infectious proteins

Question 10

What are the 2 types of fungi?

Answer 10

Yeasts and moulds

Question 11

Defining characteristics of yeasts?

Answer 11

• Single called fungi
• Budding
• Used in bread and beer production
• Some cause infections eg Candida albicans (thrush)

Question 12

Defining characteristics of moulds?

Answer 12

• Threads of cells (hyphae)
• Breakdown dead organic matter
• Reproduce sexually and asexually
• Used in antibiotic production (eg penicillin)
• Some can be eaten others cause infections