Microbiology (Fungi)

Name 3 types of nutrition employed by fungi and give an example in each case.

Saprophytic, Rhizopus. Parasitic, Athlete foot. Mutualistic, Lichen

Name beneficial and harmful fungi.

Beneficial; yeast for baking, brewing, penicillin antibiotic, edible. Harmful; poisonous, food rot, dry rot

Describe sexual reproduction in Rhizopus.

Haploid, positive and negative strains, side by side, progametangia, gametangia, diploid, zygote, zygospore, resistant, dispersed, germinates in suitable conditions, haploidspores produced

Write a balanced chemical reaction for anaerobic respiration in yeast.

C6H12O6 = 2C2H5OH + 2CO2

Is yeast prokaryotic, explain your answer.

No, has membrane bound nucleus and organelles

Describe an experiment to show leaf yeast.

Collect ash leaf, stick to Petri dish lid, underside facing down with vaseline, minimum opening, incubate 25OC for 3-4 days, invert after 1 day, pink blobs under leaf

Give a possible reason why no leaf yeast grew.

Wrong time of year, recent rain

How do you identify leaf yeast?

Shiny, pink blobs

What does sterile mean?

No microorganisms

What does aseptic mean?

No pathogenic organisms

How did you know when formation had ended?

No bubbles, solution clears

How did you identify ethanol?

Add potassium iodide, sodium hypochlorite, heat gently, yellow colour positive

Making Ethanol

Boil tap water to remove oxygen and sterilise, allow to cool and add glucose as the substrate, add yeast and mix, stopped and fit fermentation lock, this gives anaerobic conditions, control; same set up without yeast, as fermentation continues bubbles of CO2 are produced and solution is cloudy, leave for several days at 25C until fermentation is finished

Columella

Separates spores from sporangiophore

Apophysis

Swelling below sporangium

Sporangiophore

Upright hypha with sporangium at the top

Stolon

Hypha growing over the substrate surface

Sporangium

Bag that produces and releases haploid spores

Spores

Unicellular, Haploid, Asexual reproductive and dispersal agents

Spore germination

Beginning of growth of a new haploid mycelium