cryptophytes

Question 1

what are the slipper shaped algae called

Answer 1

cryptophytes

Question 2

what is the single defining feature of cryptophytes (if this is absent then it is not a cryptophyte)

Answer 2

the sub apical notch

Question 3

describe the flagella of cryptophytes

Answer 3

they are biflagellated - both flagella emerge from the top of their cell and are obvious

Question 4

what are the similarities between cryptophytes and euglenoids

Answer 4

• both are bi flagellated (cryptophytes you can see both, euglenoids you only see one)
• and both are single celled

Question 5

what environments are cryptophytes found in

Answer 5

cold and dark environments

Question 6

are cryptophytes heterotrophic, phototrophic, or mixotropohic

Answer 6

mixotrophic -they can turn on and off being photoautotrophic

Question 7

describe the sexual reproduction in cryptophytes

Answer 7

• they are asexual but recently were inferred to be sexual based on the diploid and haploid morphs of the same species

Question 8

describe the cryptophyte stress response

Answer 8

• they secrete mucilage and aggregate into a resting stage called a palmella (so settle into a big mass)
• they also abandon their flagella when stressed out
• so similar response to euglenoids?

Question 9

cryptophytes are the evolutionary product of what endosymbiosis event

Answer 9

secondary endosymbiosis - so have a 3 layered membrane around the chloroplast

Question 10

do cryptophytes have a nucleomorph

Answer 10

they often do

Question 11

describe some of the general features of cryptophytes

Answer 11

• stigma
• vestibulum
• contractile vacuole
• 3 membrane chloroplast
• nucleomorph
• 2 visible flagella near sub apical notch
• nucleomorph
• periplast

Question 12

what does the outside of cryptophytes look like

Answer 12

it has a periplast

Question 13

compare the outside of cryptophytes to euglenoids

Answer 13

• cryptophytes have periplast while euglenoids have pellicle/lorica

Question 14

describe the pigments in cryptophytes

Answer 14

• they have chlorophyll a and c
• have phycobilin’s like cyanobacteria
• have alloxanthin (euglenoids had astaxanthin)

Question 15

which group has astaxanthin and which group has alloxanthin

Answer 15

astaxanthin - red euglenoids
alloxanthin - cryptophytes

Question 16

what structure provides structural support to the cryptophytes

Answer 16

the periplast

Question 17

describe the cryptophyte furrow

Answer 17

in primitive cryptophytes the periplast does not cover the vestibulum, leaving a furrow to facilitate feeding - so by the sub apical notch where the flagellum comes out there is the opening called the furrow to help with feeding

Question 18

what is the cryptophycean gullet

Answer 18

this is when the periplast covers the vestibulum - so they don’t have an opening for consuming bacteria –> so these species of cryptophytes are considered less of predators because their opening for consuming bacteria is small and constricted

Question 19

difference between furrow and gullet in cryptophytes

Answer 19

• furrow –> periplast doesn’t cover the opening near the sub apical notch where the flagellum come out
• gullet –> periplast covers the vestibulum

Question 20

describe armored cryptophytes

Answer 20

they have ejectosomes that can flay out but stay tethered to the cell - can either be to capture prey or for evasion from a predator

Question 21

Describe the habitat of cryptophytes in lakes in particular

Answer 21

so cryptophytes are found in cold and dark environments generally but in lakes they are in the colder deepwater habitats near the thermocline (the physical barrier between to warm area at the top and the cold area at the bottom) - they are mixotrophic

Question 22

describe osmotrophic cryptophytes

Answer 22

they show tumbling chemotaxis to search for dissolved organic matter

Question 23

do cryptophytes contain phycoerythrin

Answer 23

yes many do

Question 24

What happens in cryptophytes when they are under light limitation

Answer 24

their phycoerythrin: chlorophyll a ration increases due to increased production of the phycobilin

Question 25

What happens in cryptophytes when they are under nutrient limitation

Answer 25

their phycoerythrin: chl ratio declines

Question 26

Do cryptophytes display chromatic acclimation

Answer 26

yes - through manipulation of their phycoerythrin: chlorophyll a ratio