Chapter 32 reading Flashcards
What is the reason for their being a lack of dead organic matter (d.o.m.) in tropical rainforest (and other ecosystems)?
fungi - they are responsible for decomposition of plant and animal tissues on land
What are features of fungi regarding consumption and access to energy?
depend on pre formed molecules for both carbon and energy
no organs, so absorb organic molecules directly thru cell walls
What are two major problems with no organs and reliance on pre formed carbon and energy for fungi?
more complicated molecules do no pass thru the cell wall
no means of locomotion
how do fungi deal with inability of larger molecules to pass thru cell wall?
fungi secrete enzymes that break down starch or cellulose
how do fungi deal with inability to move?
use process of growth to find nourishment - hyphae
What are hyphae?
highly branched, multicellular filaments, long & thin - provides large surface area for absorbing nutrients
What is mycelium?
the network of branching hyphae that forms the body of a fungus
Where are enzymes for breakdown of starch and cellulose secreted?
tip of the hyphae
What is the material of cell wall of hyphae?
chitin
What does chitin provide hyphae with?
a strong but flexible cell wall
What is chitin?
modified polysaccharide that contains nitrogen
What do hyphae and the mycelium formation allow for fungi to do?
grow between resource patches and produce reproductive structures like mushroom above ground
What do molecules that are absorbed by hyphae do? (chain reaction)
they drive osmosis which increases turgor pressure which increases growth and respiration in hyphae which decreases turgor pressure
= bulk flow
What does a continuous stream of cytoplasm in fungi do?
allows for movement of materials by bulk flow in mycelium
What are septa?
partitions between cell, has pores that allow transport of solutes along hypha
What is the function of septa?
when hyphae are damaged, sealing mechanism plugs pores preventing loss of pressurised cytoplasm
What is an example of a fungi that does not produce hyphae?
yeast
What is yeast?
single-celled fungi in moist, nutrient rich environments
Why don’t yeast have hyphae?
lost from descendants by convergent evolution
How do yeast divide?
by budding - a small outgrowth that increases in size and eventually breaks off to form a new cell
Where is yeast commonly found?
on surfaces of plants and sometimes on surfaces of animal gut
WHat are uses of yeast?
leavened bread, alcoholic bevs, in lab studies of genetics
What do fungi convert d.o.m. too?
CO2 and H2O