fungi

Question 1

give 5 characteristics of fungi

Answer 1

reproduce by means of spores, do not have chlorophyll, always heterotrophic, have cell walls made from chitin, body structure consists of tubes called hyphae which form mycellium

Question 2

what is a hypha/hyphae

Answer 2

a tube/filament in a fungus

Question 3

what is mycelium

Answer 3

a visible mass of hyphae

Question 4

name the two types of nutrition of fungi

Answer 4

parasitic and saprohpytic

Question 5

give an example of a parasitic fungi

Answer 5

athlete’s foot, dutch elm disease

Question 6

give an example of a saprophytic fungi

Answer 6

dry rot, mildew

Question 7

what are obligate fungi

Answer 7

can only lvie on ive hosts and do not normally kill their host e.g rust diseases

Question 8

what are faculative fungi

Answer 8

cause soft rots in fruits, may kill the host + feed on dead remains

Question 9

explain 4 features of the structure of rhizopus

Answer 9

multi-cellular, aseptate (no cross walls dividing the cytoplasm into seperate cells), stolons (grow horizontally on top of substrate… digest food by enzymes), rhizoids (anchor the mould… absorb food), sporangiophores ( function in reproduction), mycelium (mass of hyphae which absorb digested nutrients)

Question 10

what are the two ways rhrizopus can reproduce

Answer 10

sexually/asexually

Question 11

describe how rhizopus sexually reproduces

Answer 11

sporangiophores grow upwards from the substrate… tips swell and produce sporangium whos content divides by mitosis to form spores. dry conditions… sporangium dries out and releases many spores

Question 12

describe how sexual reproduction takes place in rhizopus

Answer 12

plus and minus strains of hyphae grow close together… swellings form opposite each other. swellings touch + nuclei move into each swelling forming progametangia… cross walls produced to form gametangia which are held in place by suspensors… walls between gametangia dissolve… many fertilisations between nuclei produce diploid zygote nuclei… tough walled balck zygospore forms… remains dormant for months… germinates by meiosis. hypahe grows out of the zygospore and produce sporangium

Question 13

list a benefit of fungi

Answer 13

produce penecillin, used for brewing/baking, mushrooms

Question 14

list problems with fungi

Answer 14

causes potato blight, dry rot, thrush, ringworm

Question 15

what is another name for yeast

Answer 15

saccharomyces

Question 16

give 4 structural features of yeast

Answer 16

unicellular, oval shape, cell wall made of chitin, granular cytoplasm, eukaryotic, large vacuoles

Question 17

describe how budding takes place

Answer 17

bulge forms on side of cell… enlargens and fills with cytoplasm… nucleus divides in two (mitosis), one goes into bud… bud can remain attachted or separate and form a new colony

Question 18

economic importance of fungi

Answer 18

brewing industry… respire yeast into ethanol… baking,co2 produced by yeast causes dough to rise

Question 19

define asepsis

Answer 19

making sure no disease causing micro-organisms are present

Question 20

give methods of achieving asepsis

Answer 20

sterilization of working are + equipment before and after use… flaming of containers, needles and loops… containment methods and safe disposal of unwanted materials afer use

Question 21

give methods of achieving asepsis

Answer 21

sterilization of working are + equipment before and after use… flaming of containers, needles and loops… containment methods and safe disposal of unwanted materials after use

Question 22

define sterile

Answer 22

the process of killing all microorganisms

Question 23

give a method that is used to achiece sterility

Answer 23

by moist heat using an autoclave

Question 24

experiment: to investigate the growth of leaf yeast

Answer 24

collect leaves from sycamore tree… wash hands and bench with aseptic solution… sterilise a forceps by holding it in bunsen burner flames… obtain two sterile petri dishes with agar (growth medium)… used sterilised forceps to pick up leaf… flame a inoculating loop and use it to place a small blob of vaseline on the lid of the petri-dish then reflame forceps… attach leaf to upper surface of the petri dish so the leaf’s under surface is facing the agar as microorganisms grow on the underside… reflame forceps. control: wash both sides of leaf with aseptic solution, then with forceps attach it to upper surface of the second petri dish. seal both sides with parafilm. leave petri dishes in incubator @25 degrees upside down for 3 days ( bacteria grow best in these conditions). result: circular red/pink colonies grow on the surface of the petri dish. sterilise and dispose of all equiment at the end