Fungi

Question 1

In relation to micro-organisms such as bacteria and fungi, describe their
distribution in nature.

Answer 1

they can survive in all habitats

they are found everywhere

Question 2

Explain sterility.

Answer 2

absence of all (micro) organisms

Question 3

Explain asepsis.

Answer 3

absence of pathogens

Question 4

Definition of sparophytic?

Answer 4

(organism that) feeds on dead organic matter

Question 5

Definition of parasitic?

Answer 5

(organism that) feeds on another living organism causing it harm

Question 6

Sexual reproduction in Rhizopus results in the formation of a thick-walled, dormant structure that can survive a long time in unsuitable conditions. What is the name of this structure?

Answer 6

zygospore

Question 7

What happens to the zygospore if
suitable conditions return?

Answer 7

germinates

Question 8

Give 2 examples of beneficial fungi.

Answer 8

edible mushrooms

yeast

Question 9

Are fungi eukaryotic or prokaryotic? Explain.

Answer 9

eukaryotic: have a nucleus and membrane bound organelles

Question 10

Fungi have cell walls usually made up of a carbohydrate called?

Answer 10

chitin

Question 11

Are fungi heterotrophic or autotrophic? Explain.

Answer 11

heterotrophic: dont make their own food/they take in food from other organisms

Question 12

How do fungi reproduce?

Answer 12

spores

Question 13

Fungi are made up of threads/tubes called?

Answer 13

hyphae

Question 14

Hyphae form a visible mass called?

Answer 14

mycelium

Question 15

In terms of nutrition, fungi are either?

Answer 15

parasitic or saprophytic

Question 16

Name the 2 types of parasites.

Answer 16

obligate, facultative

Question 17

Definition of obligate parasites? Give an eg.

Answer 17

get food only from a live host (don’t kill host)
Eg: athletes foot

Question 18

Definition of facultative parasites? Give an eg.

Answer 18

get food from a dead or living host (may kill host)
Eg: wood rot

Question 19

Most fungi are? Elaborate and give 2 examples.

Answer 19

saprophytes.
commonly found in the soil/on rotting leaves/trees/dead animals.
Eg: mushrooms, moulds (rhizopus)

Question 20

Saprophytic fungi act as? Describe

Answer 20

decomposers: as material is digested, minerals are released and recycled.

Question 21

How can you distinguish edible vs poisonous fungi?

Answer 21

using a key

Question 22

Name two edible fungi.

Answer 22

field mushroom (chestnut)
truffle

Question 23

Name two poisonous fungi.

Answer 23

destroying angel
death cap

Question 24

Death from poisonous fungi is usually due to?

Answer 24

liver and intestine damage/failure

Question 25

Mode of nutrition for rhizopus?

Answer 25

saprophytic/heterotrophic

Question 26

Name a common bread mould.

Answer 26

rhizopus

Question 27

Where does digestion take place for rhizopus?

Answer 27

outside the fungus

Question 28

Function of stolon?

Answer 28

spread/growth/reproduction/colonisation

Question 29

Function of rhizoid?

Answer 29

anchorage/secretion/absorption (of nutrients)

Question 30

Function of spores?

Answer 30

(asexual) reproduction/dispersal

Question 31

Definition of sporulation?

Answer 31

is the process of making spores

Question 32

Name two unsuitable conditions.

Answer 32

drought unsuitable temperatures

Question 33

Explain asexual reproduction in rhizopus in 3 steps.

Answer 33

1) sporangium dries out in the right conditions and opens releasing spores. 2) all spores have a haploid nucleus 3) each spore grows into a new hyphae if it lands on a suitable substrate, eg bread.

Question 34

Rhizopus have 2 seperate chemically opposite strains, called?

Answer 34

plus + and minus - strains

Question 35

Explain sexual reproduction in rhizopus in steps.

Answer 35

1) hyphae from a + and - strain grow close, swellings grow on both strains and touch. 2) nuclei from both hyphae move into these swellings and form progametangia. 3) cross walls form to produce gametangia which are held in place by suspensors. 4) walls of gametangia dissolve and a number of fertilisations take place producing diploid zygote nuclei. 5) black zygospore forms around these nuclei. 6) in suitable condiitons, zygospore germinates by meiosis haploid hypha grows out of zygospore a sporangiophore and sporangium develop

Question 36

Comment on shape of yeast.

Answer 36

round or oval

Question 37

Are yeast multicellular or unicellular?

Answer 37

unicellular (single-celled)

Question 38

Yeast have a large vacuole and cell walls made of?

Answer 38

chitin (carbohydrate)

Question 39

Do yeast have hypha? What effect does this have?

Answer 39

no hypha, have a dense grainy cytoplasm and contain food vacuoles

Question 40

How do yeast respire?

Answer 40

anaerobically (fermentation)

Question 41

Do yeast produce sexually or asexually? What is this process called?

Answer 41

asexually, by budding

Question 42

Describe in detail the process of asexual reproduction in yeast cells.

Answer 42

Organelles/nucleus divides, new bud forms, organelles/nucleus move into bud new, cell detaches (or can remain attached), colony forms.

Question 43

Two advantages of asexual reproduction?

Answer 43

very fast, offspring show no variation

Question 44

Two disadvantages of asexual reproduction?

Answer 44

increased chance of disease, no variation

Question 45

ECONOMIC IMPORTANCE OF FUNGI - benefits?

Answer 45

- yeast used in brewing to produce wine/beer - mushrooms as a food source - baking industry - production of antibiotics

Question 46

ECONOMIC IMPORTANCE OF FUNGI - disadvantages?

Answer 46

- fungal infections can destroy crops, potato blight - fungi can spoil food, rhizopus on bread - fungi can cause disease on humans, athletes foot

Question 47

Name some asepctic techniques.

Answer 47

- using disinfectant (equipment/hands/bench) - flaming equipment like forceps - minimal opening of plates/seal them - wear gloves/hand sanitizer/soap