Lecture 21

Question 1

2 major groups of fungi?

Answer 1

Yeast & mold

Question 2

What is this grouping (fungi) based on

Answer 2

body plan

Question 3

Which group of fungi are almost always found as unicellular organisms?

Answer 3

Yeast

Question 4

Which of the 2 groups of fungi always form hyphae (the other group only rarely forms hyphae)?

Answer 4

mold

Question 5

What is the difference between hypha (pl. hyphae) and mycelium (pl. mycelia)?

Answer 5

A mycellium is made up of hyphae that have branched.

Question 6

Are hyphae made up of 1n or 2n cells?

Answer 6

1n

Question 7

How is the function of hyphae in a fruiting body different from the hyphae that form mycellium?

Answer 7

The hyphae in a fruiting body function in reproduction (spore production) while the hyphae that form mycelium can be involved in digesting & absorbing nutrients as well as in reproduction. In other words, the hyphae in a fruiting body only function in reproduction (not involved in nutrition).

Question 8

What is the name of the structure that looks white and slightly brownish “fuzz”? (rotten strawberries)

Answer 8

Mycellia

Question 9

do spores, hyphae, yeast have a cell wall?

Answer 9

yes.

Question 10

What is a spore?

Answer 10

A single-celled reproductive structure that is dispersed into the environment & can grow into a hypha.

Question 11

2 structures that contain spores

Answer 11

Sporangia & fruiting bodies.

Question 12

Considering fungi’s mode of nutrition, which of the following organelle(s) would you expect to see an abundance of? Justify your answer.

Answer 12

vesicles. Golgi. rER.
While you will have all of these, the question is referring to the fact that fungi secrete exoenzymes in order to decompose organic matter; these exoenzymes are made by the endomembrane system

Question 13

Fungi characteristics

Answer 13

1. Eukaryotes, most multicellular
2. Decomposers (by def’n are heterotrophic): nutritional mode & role in ecosystem
3. Cell walls (made of chitin): can withstand osmosis (like plant cells, won’t lyse in water)
4. Sexual (genetic diversity) & asexual reproduction
5. Non-motile: has major impact on their “lifestyle”.
6. haploid cells

Question 14

where do fungi live?

Answer 14

Grow best in moist LAND habitats but found almost everywhere on land (wherever organic material is present)
Mostly underground

Some live in digestive tract of sheep & cattle
Grow on bread, strawbs, animal poo
Almost all live in plant roots
Most yeasts, morels, lichens, plant roots
Mushrooms, on tree trunks

Question 15

fungi tolerance (living conditions)

Answer 15

Can tolerate huge range of pH (2-9)
Some can grow in salt, sugar (unlike most bacteria)
Wide temperature range: Can grow even in fridge

Question 16

Nutrition of fungi? how is that done

Answer 16

Heterotrophic
Secrete exoenzymes: Digest food then absorb digested molecules, + minerals, vitamins, water either directly across the plasma membrane or by cytosis

Decompose (break down) dead organic material using exoenzymes (saprophytic)

• recycle vital nutrients (organic molecules & minerals)
• essential for most terrestrial ecosystems (along with bacteria)

Question 17

Main storage carb in fungus is __

Answer 17

glycogen (as in animals).

Question 18

YEASTS: mostly _

Answer 18

UNICELLULAR

Question 19

Most MOLDS are : __

Answer 19

MULTICELLULAR

Question 20

Yeast reproduce mostly_

Answer 20

asexually (mitosis) (budding)

but sometimes sexual reproduction by release of 1n spores from 2n sporangia

Question 21

molds are mostly made up of?

Answer 21

hyphae

Question 22

how does hyphae form?

Answer 22

When a fungal spore (single cell) lands in a suitable spot, it germinates then undergoes mitosis to form a multicellular hypha

Question 23

Mitosis of haploid cells of fungi leads to __

Answer 23

formation of a hypha

Question 24

Hyphae can branch to form:

Answer 24

mycelium (used to obtain nutrients) (FOOD)

sporangia or fruiting bodies (for reproduction)

Question 25

what does Mycelia do

Answer 25

Infiltrate organic matter & absorb nutrients

Question 26

world's biggest and oldest fungi?

Answer 26

The Humongous Fungus Armillaria solidipes is among the largest and oldest living organism

Question 27

Sporangia?

Answer 27

structure where spores are made

Question 28

are Spores motile?

Answer 28

Spores are non-motile | Dispersed by wind, water, or animals

Question 29

how are spores dispersed?

Answer 29

Dispersed by wind, water, or animals

Question 30

asexual reproduction in fungi? (how and what's the result)

Answer 30

asexual reproduction by mitosis, spores released from sporangia 1n Spores ↓ Mitosis 1n Hypha ↓ Mitosis 1n Sporangia differential gene expression 1n Spores

Question 31

sexual reproduction in fungi? (how and what's the result)

Answer 31

meiosis produces genetically distinct 1n spores that are released from sporangia/fruiting body ``` Meiosis of 2n cells: makes four 1n cells Each 1n cell can grow into a sporangium through mitosis Release of spores Formation of hyphae Sexual or asexual repro ```

Question 32

Shape and size of fruiting bodies depends on what?

Answer 32

The shape & size of fruiting bodies depends on fungal species & whether spores are dispersed by water, wind, or animals

Question 33

Ecological Significance of Fungus

Answer 33

Most fungi are DECOMPOSERS. Get nutrients from dead organic matter: fallen trees, animal corpses… Symbiotic relationships: Mutualism: Mycorrhizae, lichens, & some cases with animals A small fraction are Parasites: cause disease/kill plants & animals

Question 34

__& __are the major decomposers of ecosystems.

Answer 34

bacteria and fungi

Question 35

how do fungi penetrate on large pieces of organic matter (unlike bacteria)

Answer 35

fungi can use their hyphae to penetrate larger pieces of organic matter (are found on surface & within the matter)

Question 36

Mycorrhizae ?

Answer 36

Type of fungus that forms a mutualistic relationship with plants (lives in their roots) Mycorrhizae colonize the roots of over 90% of all vascular plants & are present in nonvascular plants

Question 37

Mutualism: b/w a fungus + a phototroph (algae or cyanobacterium) . who benefits what

Answer 37

Phototroph provides: organic food molecules | Fungus provides a home: ie a suitable physical environment for growth, CO2, water & minerals

Question 38

Economic importance of fungi

Answer 38

Mutualism, parasitism have economic impacts Fungi also source of medicines - Antibiotics

Question 39

importance of fungi on Food & drink

Answer 39

Baker’s & brewer’s yeast Make alcohol, release CO2 by fermentation Sugar from fruits (ex grapes) → alcohol in wine Sugar from grains (ex barley) → alcohol in beer Sugar + dough → CO2 bubbles make bread rise