Fungi

Question 1

What are the four sub-types of fungi and how are they distinguishable

Answer 1

Ascomycota
Basidomycota
Zygomycota 
Chytridomycota 
Distinguishable by the characteristics of their reproductive structures

Question 2

How can fungi have two different names?

Answer 2

Teleomorph: form of the fungus that produces sexual reproduction structures
Anamorph: asexual form of the fungus

Question 3

Why are arbuscular mycorrhiza (AM) so important in the ecosystem?

Answer 3

AM are the main absorbing organ of many plants

Question 4

What are septa?

Answer 4

In basiodomycetes and ascomycetes, hyphae are subdivided into compartments by crosswalls; septa. Septa limit damage to mycellium by making it possible to seal off damaged compartments

Question 5

What is ergosterol

Answer 5

Ergosterol is in fungal plasma membranes which has many functions, comparable to cholesterol in human plasma membrane

Question 6

How are nutrients taken up on agar?

Answer 6

Nutrient uptake is driven by the proton motive force (3 pH units, 200-300 mV) generated by ATPases through exctrusion of protons

Question 7

What are the function of vacuoles in fungi

Answer 7

digestion of compounds, storing of metabolites, cations and regulate cytoplasmic pH and ion concentration.

Question 8

What is hyphae and how does hyphae extend

Answer 8

Hyphae extend apically and branching, this produces a network of filaments called mycelium

Question 9

How are nutrients taken up by hyphae when they are aerial

Answer 9

Evaporation of water at the tip if growing aerial hyphae generates a water flow, carrying nutrient to their tips

Question 10

What is the storage zone of fungi

Answer 10

As hyphae grow, excess nutrients are stored in the storage zone, and deposited as glycogen deposits or lipid droplets. Some of these nutrients are then used to produce reproductive structures.

Question 11

What is branching

Answer 11

Branching occurs when the nutrient supply exceeds what is required to sustain growth at tip (exponential growth)

Question 12

What are haustoria and nematode traps

Answer 12

Haustoria are complex morphological structures which conduct plant cell invasion in pathogenesis and mutalism; mycorrhiza) Nematode traps which allow fungi to trap and consume nematodes (roundworms)

Question 13

What is the absorption zone of fungi

Answer 13

The breakdown products of nutrients are absorbed and converted into biomass and increase length of hyphae

Question 14

What are Blastocladiales

Answer 14

Saptrotrophs (living on plant or animal debris) in fresh water, mud or soil

Question 15

What is dimorphism

Answer 15

When a fungi species change morphology, for example some mucorales can grow anaerobically and this is associated with a change from hyphal morphology to yeast morphology.

Question 16

What is the importance of glomales?

Answer 16

Glomales form all vesicular abuscular mycorrhizas (VAMs) which are the main absorbing organs of these plants

Question 17

How to detect rare species by PCR?

Answer 17

Firstly need to design primers that can be used to amplify parts of the species ribosomal RNA encoding genes, if you get a PCR product that indicates that its present, but also compare with sequences in online databases

Question 18

What are primary and secondary metabolites

Answer 18

Primary metabolites are directly involved in the normal growth of cell (ethanol in yeast) and secondary metabolites aren’t directly involved in the normal growth (penicillin in penicillium)

Question 19

What is the main difference between cellular and acellular amoeba?

Answer 19

In vegetative state cellular amoebae is in a haploid ameboid cell, in acellular amoebae it is a multinucleate diploid called a plasmodium. This plasmodium develops into a fruiting body which disperses spores.

Question 20

Describe a biological process that has prevented the development of a vaccine against malaria.

Answer 20

Constantly changing surface proteins allows plasmodium to evade the immune response, plasmodium has 60 genes and only one is shown, which means the immune response is for that one but it has 59 which can evade the immune response.

Question 21

What are hydrogenosomes

Answer 21

In neocallimastigales derived from mitochondria. If enough of the NADH generated in glycolysis is used (oxidized) to reduce molecules in anabolism, then it is not necessary to reduce all pyruvate in fermentation to restore NAD. Under these circumstances, the hydrogenosome can generate 4 ATP per glucose.

Question 22

what do the regulatory proteins of saccharomyces cerevisae do

Answer 22

Three regulatory proteins encoded by s.cerevissae mating type locus can determine cell type by regulating the expression of other genes, allowing s.cerevisae to change its mating type.