Euglenoids

Question 1

describe euglenoids in terms of being more plant or animal like

Answer 1

they are half plant/half animal –> they can be more animal like if the conditions require it

Question 2

Euglenoids are the product of what endosymbiosis event

Answer 2

secondary endosymbiosis
so chloroplast has three membranes

Question 3

do euglenoids have a nucleomorph (a reduced nucleus)

Answer 3

No, the euglenoid nucleomorph has been completely assimilated and broken down so you don’t see a nucleomorph in the chloroplast

Question 4

photoautotrophic euglenoids are believed to be the evolutionary product of what endosymbiosis event

Answer 4

secondary endosymbiosis where there was ingestion of green algae resulting in the chloroplast and the nucleus of the original endosymbiote has been destroyed

Question 5

Describe the early bacterivores of euglenoids

Answer 5

• they did phagotrophic consumption of bacteria (so this is considered the earliest mode of nutrition by plastidless euglenoids - the ones with no chloroplast)

Question 6

Describe the entosiphon of the euglenoids

Answer 6

this was a early bacterivore that had a feeding funnel consisting of ingestion rods to help it take in bacteria because the early bacterivores did phagotrophic consumption

Question 7

describe osmotrophic euglenoids

Answer 7

• these can appear colorless
• the obligate heterotroph euglenoids have lost their phagotrophic abilities and don’t have chloroplasts so they do uptake of Dissolved organic material (DOM) via osmosis
• the facultative heterotrophs/mixotrophs euglenoids can de synthesize and re synthesize their chloroplasts in response to light availability

Question 8

Are the majority of euglenoids phototrophic or heterotrophic

Answer 8

• phototrophic

Question 9

What function does the stigma of euglena serve

Answer 9

it serves a kind of phototaxis function - it doesn’t have any structural integrity to it or any structure to actually call it an eye though

Question 10

describe euglenoids in brown surface waters

Answer 10

• these are organically rich water habitats
• this is where they generally tend to be found
• they can appear as colorless heterotrophs or chl a and b containing phototrophs (but don’t completely function as plant because they don’t produce starch)
• so in most cases there is mixotrophy

Question 11

how many flagella do euglenoids have

Answer 11

• they are bi flagellate but only one can be seen with the microscope, the second one is short and sits in the vestibulum/reservoir where it stores prey items being taken in

Question 12

where is the eye spot located on euglenoids

Answer 12

near the flagella

Question 13

Where is the contractile vacuole in euglenoids

Answer 13

near the flagella and eye spot as well - it helps to clear the reservoir of debris

Question 14

What is the pellicle of euglenoids

Answer 14

this is the outer layer which can be soft or hard - depending on its rigidity it can help with propulsion

Question 15

What are paramylon granules in euglenoids

Answer 15

they store the products of photosynthesis - they produce paramylon instead of starch

Question 16

how many chloroplast are in euglenoids

Answer 16

numerous

Question 17

What do euglenoids produce instead of starch even though they contain the same chlorophyll a and b as green algae

Answer 17

they produce paramylon

Question 18

what type of reproduction do euglenoids do

Answer 18

asexual reproduction through binary fission where the cell splits down the middle and you get two euglenoids from that split

Question 19

What is the stress response done by euglenoids

Answer 19

It produces a cyst and loses its flagella and produces a sheath around it - it stays as a cyst until the stress is removed
- the cyst formation and mucilage production then binds the cell into a palmella

Question 20

compare the stress response of cyanobacteria and euglenoids

Answer 20

• cyanobacteria form akinetes
• euglenoids produce cysts

Question 21

what is the palmella

Answer 21

this is the euglenoid stress response where the cyst formation and mucilage binds the cell into a palmella (the entire population starts producing cysts)

Question 22

instead of a cell wall what do euglenoids have

Answer 22

a pellicle or in some cases they may have an outer casing of minerals and mucilage called a lorica

Question 23

how can the pellicle affect the movement of euglenoids

Answer 23

• if it is rigid then the cell has to rely on its flagellum for mobility
• if the pellicle is more flexible then the pellicle can aid in movement –> the contraction of the pellicle promotes cytoplasmic streaming (known as METABOLY)

Question 24

what is metaboly

Answer 24

this is when the pellicle helps in the movement of euglenoids
(this is basically them moving around and scrunching up and down)

Question 25

How can a lorica affect the metaboly of euglenoids

Answer 25

• lorica is an outer casing of minerals and mucilage which totally negates metaboly because it is rigid

Question 26

describe red euglenoids

Answer 26

euglenoids can produce this red pigment called astaxanthin to protect against sunlight (flamingoes eat these euglenoids and that’s why their feathers are reddish/pink)

–> astaxanthin is not an accessory pigment for photosynthesis though

Question 27

freshwater red tides are due to what

Answer 27

euglenoids producing astaxanthin

Question 28

which species is used as a model for metal tolerance and acid tolerance

Answer 28

euglenoids -they have high metal tolerance and us Metallothioneins