Fungi

Question 1

prokaryotic

Answer 1

contain no membrane bound nucleus or membrane bound organelle

Question 2

eukaryotic

Answer 2

contains a membrane bound nucleus and membrane bound organelle

Question 3

asepsis

Answer 3

excluding pathogens from as much of the environment as possible

Question 4

sterile

Answer 4

free from all micro organisms

Question 5

heterotrophic

Answer 5

organisms that are not capable of making their own food

Question 6

autotrophic

Answer 6

organisms capable of making their own food using energy

Question 7

saprophytic

Answer 7

organisms that obtain their food from dead organisms

Question 8

parasitic

Answer 8

two organisms of different species that live together where one benefits and causes harm to the other

Question 9

obligate parasites

Answer 9

obtain their food from a living host but do not kill them

Question 10

facultative parasites

Answer 10

obtain their food by killing the host and feeding on the remains

Question 11

symbiotic

Answer 11

organisms that live in close contact with a second species and at least one organism benefits

Question 12

mycology

Answer 12

study of fungi

Question 13

five kingdoms of living things

Answer 13

animalia
plantae
monera
protista
fungi

Question 14

main features of the kingdom of fungi

Answer 14

heterotrophic
eukaryotic
mainly multicellular (excl. yeast)
have cell walls made of chitin

Question 15

important structures of all fungi

Answer 15

hyphae
mycelium
cell walls made of chitin

Question 16

chitin

Answer 16

carbohydrate that gives cell wall strength

Question 17

role of parasites

Answer 17

natural selection

eg athlete’s foot

Question 18

role of saprophytic organisms

Answer 18

responsible for decomposition

eg mushrooms and mould

Question 19

examples of fungi

Answer 19

edible eg field mushrooms

poisonous eg death cap, destroying angel

Question 20

economic importance of fungi

Answer 20

beneficial fungi:
yeast - used to make bread/alcohol
source of food - eg mushrooms

harmful fungi:
infection - eg athlete’s foot
food spoilage - eg Rhizopus on bread

Question 21

rhizopus reproduction

Answer 21

asexual - by spores

sexual - by hyphae

Question 22

rhizopus mode of nutrition

Answer 22

saprophytes - feed on bread, veg. peelings

Question 23

hypha

Answer 23

single threadlike
multinucleate (haploid)

function: digest and absorb substrate

Question 24

mycelium structure

Answer 24

made up of large numbers of hyphae

Question 25

rhizoids

Answer 25

provide extra surface area for absorption, digestion of material, anchorage

Question 26

stolon

Answer 26

aerial hypha that allows rhizopus to spread

Question 27

conditions that cause rhizopus to produce seuxually

Answer 27

lack of water

unsuitable temperature

Question 28

sexual reproduction in Rhizopus

Answer 28

1. between + and - strain
2. swellings form on each hypha (progametangia)
3. swellings fuse = gametangia
4. walls between gametangia break down, nuclei from each hypha move into swellings and fuse (diploid zygote)
5. gametangia develop into zygospore
6. zygospore germinates by meiosis to produce a haploid hypha
7. sporangium develops at the tip

Question 29

asexual reproduction in Rhizopus

Answer 29

1. hypha develops into sporangiophore
2. tip of sporangiophore swells and becomes a sporangium
3. inside sporangium: haploid spores produced by meiosis
4. dry conditions: sporangium dries out, releases spores, each develop hyphae when on a suitable substrate

Question 30

economic importance of yeast

Answer 30

used in bread/alcohol production

Question 31

differences between yeast and rhizopus

Answer 31

yeast:
unicellular
no hyphae
does not produce zygospores

Rhizopus:
multicellular
has hyphae
produces zygospores

Question 32

asexual reproduction in yeast

Answer 32

budding

1. extension develops on cell (bud)
2. bud fills with cytoplasm
3. nucleus divides by mitosis
4. daughter nucleus enters bud
5. bud can either:
   - separate from parent to become new individual
   - not separate, but can itself bud. this is how long colonies of yeast spread

Question 33

advantages of asexual reproduction in yeast

Answer 33

rapid
no variation (mitosis)

Question 34

disadvantages of asexual reproduction in yeast

Answer 34

increased risk of disease

overcrowding

Question 35

experiment (before the steps)

Answer 35

nutrient used: agar
why: food source which provides a medium for yeast to grow on
leaves used: sycamore or ash
how was aseptic technique ensured:
-wash bench with Milton
-sterilise equipment (flame with bunsen)
-wash hands with soap
-minimal opening of petri dishes

Question 36

experiment method

Answer 36

1. cut and collect leaves
2. wash bench
3. flame a cork and cut out disks
4. flame forceps, allow to cool
5. carefully raise the base of the petri dish just enough to work with
6. using forceps, smear dots of petroleum jelly onto the inside of the lid. work quickly to avoid micro organisms entering
7. use forceps to attach a leaf disc to each blob of jelly
8. seal the dish with parafilm to prevent possible contamination
   examine presence or absense of colonies after incubation
   disposal: place all dishes in an autoclave

Question 37

control of experiment

Answer 37

sealed petri dish with malt agar and no leaves

show that leaf is the only course of yeast

Question 38

storage during incubation experiment

Answer 38

store all petri dishes right side up in an incubator at 20ºC for 24 hrs
turn all petri dishes upside down and incubate at 20ºC for 2-7days

Question 39

results of experiment

Answer 39

pink colonies of yeast will form

control: no change