lectures 16-18

Question 1

2 types of fungi growth

Answer 1

isometric

polarised

Question 2

hyphae microtubules

Answer 2

connect compartments allowing intercellular communication and reallocation of resources

Question 3

hyphal tips

Answer 3

are polarised
change direction
show autotropism

Question 4

septa

Answer 4

permit regulated flow of material

permit compartmentalisation of cells and therefore differentiation

Question 5

fungal cell wall

Answer 5

maintenance of cell shape

stabilisation of internal osmotic conditions - wall creates pressure, preventing excess water influx

protection against physical stress - physical coat

a scaffold for extracellular proteins and secreted enzymes - polysccharides

Question 6

what drives hyphal extension/growth

Answer 6

(1) Turgor pressure - closed hydraulic system?

(2) Steady –state or balanced lysis using
the Vesicle Supply Centre (VSC) or Spitzenkörper - organise distribution

rapid movement towards the apex of all the materials needed to create new wall, new membranes and new cytoplasmic component

Question 7

hyphae can fuse…

Answer 7

tip to tip
for sex: clamp connections
self-fusions
tip to side

to allow the formation of a complex interconnecting network - the fungal mycelium

Question 8

3 types of differentiated hyphae

Answer 8

skeletal - long, unbranched

generative - bear clamp connections or spores

binding - thick-walled and branch frequently

Question 9

conidiation

Answer 9

production of asexual spores(conidia)

Question 10

oldest spore

Answer 10

found at the top, furthest away from the mother spore

Question 11

what do protists have in common

Answer 11

all eukaryotes
all require water-based environment
all undergo mitosis

most are unicellular
most require oxygen
most are motile

Question 12

how to protists obtain nutrition

Answer 12

photosynthesis
engulfing prey/phagocytosis
symbiosis
absorption of nutrients

Question 13

how do protists move

Answer 13

pseudopodia
cilia
flagella

Question 14

alveolates

Answer 14

contain sacs below their plasma membranes
most are photosynthetic
unicellular

Question 15

dinoflagellates

Answer 15

mostly marine, photosynthetic endosymbionts, free-living
two flagella
primary producers

Question 16

apicomplexans

Answer 16

contain an apical complex that facilitates host invasion
all paarasites
complex life cycles and many hosts

Question 17

ciliates

Answer 17

cilia provide motility and feeding
Complex cellular forms; contractile vacuoles, digestive vacuoles,
Two types of nuclei – distinct role in reproduction
Most are heterotrophic; some contain photosynthetic endosymbionts

Question 18

stramenopiles

Answer 18

Two flagella of unequal length, with rows of tubular hairs along the larger flagellum
Some have lost flagella
Some are photosynthetic

Question 19

diatoms

Answer 19

Unicellular but may associate in filaments
Carotenoids give golden or brown colour
Only male gametes possess flagella
Two-piece silica (silicon dioxide) cell walls
Bilateral or radial symmetry
Synthesise Aquatic, phytoplankton “blooms

Question 20

oomycota

Answer 20

Water moulds (NOT fungi)
Saprobes and biotrophs
Important agents of disease in plants and animals
Cellulose cell wall

Question 21

rhizaria

Answer 21

Long, thin pseudopodia
Unicellular
Aquatic or soil living

Question 22

cercozoans

Answer 22

aquatic
form shell-like structures
green algal secondary endosymbionts
made from organic materials enforced with calcium carbonate

e.g. fossilised to form white cliffs of dover

Question 23

causes of coral bleaching

Answer 23

increased or reduced water temperatures
oxygen starvation caused by an increase in zooplankton
increased sedimentation (due to silt runoff)
Bacterial and fungal infections
changes in salinity
herbicides
low tide and UV exposure
elevated sea levels due to global warming

Question 24

bioluminescence

Answer 24

from dinoflagellates

from scintillons in cortical regions of cells

controlled by circadian clock and only occurs at night

enzyme = dinoflagellate luciferase

Question 25

cause of ‘red-tides’

Answer 25

toxins bind to voltage gated sodium channels