BACTERIAL, FUNGAL AND VIRAL STRUCTURE AND FUNCTION

Question 1

prokaryote vs eukaryote

Answer 1

prokaryote(bacteria and archaea) vs eukaryote (protozoa and fungi)

Prokaryote
Nucleoid
Circular DNA

Both
DNA
Ribosomes
Cell membrane
Cells

Eukaryote
Nucleus
Organelles
Linear DNA

Question 2

bacteria and archaea

Answer 2

Bacteria -
Prokaryotes, 0.2-40um, can live in environments where temperature,oxygen and nutrient requirements are met and various shapes.

Achaea-
Chemolithotrophs , euryarchaeota, crenarchaeota and many are extremophiles.

Bacteria vs archaea
Similarities
morphology , reproduction via binary fission and movement
Differences
Cell wall composition
Lipid membrane composition
Ribosome shape
Metabolic shape
Do not produce spores

Question 3

protozoa and fungi

Answer 3

Protozoa are eukaryotes, unicellular, colourless, motile and are ubiquitous

Fungi - have cell walls, produce spores, can be classified by morphology, 3 major groups e.g mould, yeast and mushrooms, have diverse habitats and are symbiotic.

Question 4

viruses

Answer 4

20-200 nm (very small)
They are particles
Nucleic acid (DNA or RNA) surrounded by a protein coat
Survive by infecting eukaryotes or prokaryotes
Helical (RNA), polyhedral, spherical and complex shapes (DNA)
Ebola virus is filamentous shaped with 50% death rate
Coronavirus is spherical shaped and killed 7 million in jan 2024
influenza - virus binds with specific receptor on host cell, endocytosis RNA is released into the cytoplasm, mRNA synthesis, RNA genome replication, protein synthesis. RNA and proteins assemble at the cell membrane and the new viral particle leaves the cell

Question 5

names for PH and tempreture extremes

Answer 5

psychrophiles - cold environments below 15 degrees
Mesophiles- warm-blooded animals, terrestrial and aquatic environments between 20-40 degrees.
Hyperthermophiles or extremophiles- found in above 45 degrees

Acidophile- pH 5 or below
Neutrophile- pH 6-8
Alkaliphile- pH above 9

Question 6

Staphylococcus aureus

Answer 6

Opportunistic pathogen that affects skin and upper respiratory tract, gram positive

Question 7

bacterial culture- nutrients

Answer 7

Requires: carbon, energy, nitrogen, phosphorous and mineral salts
General purpose media- non-selective and growth of many microorganisms
Selective media- inhibitory substances and growth of specific microorganisms
Enrichment media- improves growth
Differential media- distinguish organisms

Question 8

gram stain

Answer 8

Fix to slide -> crystal violet -> iodine-> ethanol-> safranin
Gram positive goes purple/blue and gram negative goes to pink