fungi

Question 1

features of fungi

Answer 1

-they do not make their own food
-they are mostly multicellular
-they are made up of threads called hyphae
-hyphae combine in masses to form mycelium
-their walls are made of a carbohydrate called chitin

Question 2

how do fungi take in food

Answer 2

they are heterotrophs so they take in food made by other organisms

Question 3

name the two types of fungi

Answer 3

parasitic
saprophytic

Question 4

saprophytic fungi

Answer 4

-most fungi are saprophytic
-they obtain nutrients from dead material
-as they digest it minerals are released and recycled
-they play a vital role in the environment as they are responsible for decay

Question 5

name some saprophytic fungi

Answer 5

mushrooms
moulds

Question 6

parasitic fungi

Answer 6

-absorb their food from live hosts
-they get their food mostly from plants
-some live on animals eg athletes foot

Question 7

two kinds of parasitic fungi

Answer 7

obligate parasites
-live on host but do not normally kill them
facultative parasites
-kill the host and feed on the remains

Question 8

example of a symbiotic relationship of fungi and another organism

Answer 8

lichen
combination of a fungus and an algae

Question 9

what does rhizopus consist of

Answer 9

-threadlike structures called hyphae
-are tubular with no crosswalls
-are multinucleate, each nucleus is a haploid

Question 10

what are large numbers of hyphae called

Answer 10

mycelium

Question 11

role of hyphae

Answer 11

digest the substrate on which they grow

Question 12

function of rhizoids

Answer 12

provide extra surface area for absorption of the digested material

Question 13

what are stolons

Answer 13

arial hyphae which allow rhizopus to spread sideways

Question 14

nutrition of rhizopus

Answer 14

-rhizopus secrete enzymes out onto starchy food
-digestion takes place outside the fungus
-the digested nutrients are absorbed
-rhizoids give a large surface area for this to happen

Question 15

what is asexual reproduction in a rhizopus called

Answer 15

sporulation

Question 16

how does sporulation work

Answer 16

1. sporangiophores grow up from the substrate after a number of days
2. cells within the sporangium divide by mitosis to produce spores (haploid)
3. the sporangium dries out in the right conditions and opens releasing many spores
4. each spore will grow into a new hypha and mycelium if it lands on a suitable substrate

Question 17

what is sporulation

Answer 17

the process of making spores

Question 18

when does sexual reproduction in rhizopus happen

Answer 18

-under adverse conditions like extreme temperatures
-can only happen between a plus and a minus strain

Question 19

how does sexual reproduction in rhizopus work

Answer 19

1. when hyphae from opposite strains grow close together swellings grow on both strains and touch each other
2. nuclei from both hyphae move into these swellings which are now called progametangia
3. cross walls form to produce gametangia
4. the walls of the gametangia dissolve and a number of fertilisations take place producing diploid zygote nuclei
5. a zygospore forms around these nuclei
6. when conditions are suitable the zygospore germinates by meiosis
7. a hypha grows out of the zygospore and produces a sporangium at the tip
8. the sporangium opens releasing many haploid spores which grow into new individuals

Question 20

what is asexual reproduction in yeast called

Answer 20

budding

Question 21

explain the process of budding

Answer 21

1. the nucleus of the parent cell divides by mitosis
2. one of the daughter nuclei enters a small developing bud on the outside of the yeast cell
   3.usually the bud separates from the parent to become an individual cell, however sometimes this does not happen and the daughter cell itself buds, in this way long colonies of yeast cells can develop

Question 22

benefits of fungi

Answer 22

-yeasts can be used to make bread and alcohol such as wine and beer
-can be used as a source of food eg mushrooms

Question 23

harmful effects of fungi

Answer 23

-can attack crops eg corn and wheat, causes major financial losses as a result
-athletes foot and ringworm can affect animals
-can spoil food eg rhizopus grows on bread