Lab 3 (Protists - 1 of 2)

Question 1

What are two common characteristics of protists?

Answer 1

most abundant in moist habitats
mostly microscopic in size

Are not a well-defined, monophyletic group

Question 2

What is one method for classifying protists?

Answer 2

ecological role:
algae
protozoa
funguslike

Question 3

How do protists reproduce?

Answer 3

asexually - fission

sexually - syngamy or conjunction

Question 4

algae

Answer 4

photosynthetic, lack multicellular sex organs

Question 5

How are algae grouped?

Answer 5

pigments (energy storage, cell wall composition, color)

cellular organisation:
unicellular (one cell, may or may not be motile)
filamentous (chains of cells attached end to end)
colonial (groups of cells attached in a non-filamentous manner)

Question 6

Chlamydomonas

Answer 6

motile (flagellated), unicellular green alga found in soil, lakes, and ditches
usually reproduces asexually via mitosis; sexual reproduction is a response to unfavorable conditions

Question 7

What is the sexual lifecycle of Chlamydomonas?

Answer 7

vegetative cells undergo mitosis to produce gametes
Gametes fuse to form a diploid zygote (resting stage of lifecycle)
Gametes are isogamous
Syngamy - pairing and fusion of haploid gametes to form diploid cells
Zygote surrounds itself with resistant surface to form zygospore
Zygote undergoes meiosis to produce haploid spores
Spores develop into an adult without fusing with another cell

Question 8

isogamous

Answer 8

gametes of two strains are identical in shape and appearence (eg. Chlamydomonas)

Question 9

zygospore

Answer 9

resistant surface formed around zygote (eg. Chlamydomonas)

Question 10

spores

Answer 10

haploid individuals produced by zygote via meiosis; reproductive cells that can develop into an adult without fusing with another cell (eg. Chlamydomonas)

Question 11

Spirogyra

Answer 11

filamentous green algae
grows in running streams of cool fresh water, secretes mucilage that makes it slippery
reproduces by conjugation
Contains spiral chloroplasts

Question 12

Cladophora

Answer 12

filamentous green algae
coarse appearence and texture
Exists in haploid and diploid forms at maturity (sporophyte and gametophyte)
reproduces by alternation of generations

Question 13

conjugation

Answer 13

filaments of opposite mating types lie side by side and form projections that grow towards each other
touch and form a conjugation tube
Motile (-) strain contents move into nonmotile (+) strain contents
gametes fuse and develop a zygote with zygospore
Zygospore released when filament disintegrates
Zygospore undergoes meiosis to form haploid cells that become new filaments

Question 14

alternation of generations

Answer 14

alternating haploid and diploid stages of a life cycle

Question 15

sporophyte

Answer 15

diploid stage of lifecycle, produces spores

Question 16

gametophyte

Answer 16

haploid stage of lifecycle, produces gametes

Question 17

Volvox

Answer 17

colonial green algae
many chlamydomonas-like cells bound in a common spherical matrix; two flagella from each cell provide motion
Reproduces by oogamy (sexually) or asexually by producing a daughter colony that bulges inward and is initially held within the parent colony

Question 18

oogamy

Answer 18

motile sperm swim to and fuse with non-motile eggs to form diploid zygote
zygote enlarges and develops into zygospore, which is released when the parent colony disintegrates
Undergoes meiosis to produces haploid cells
Undergo mitosis to become a new colony

Question 19

Phylum Phaeophyta

Answer 19

brown algae - marine algae with complex structure (no unicellular or colonial)
Grow in cool water and contain fucoxanthin

Question 20

Fucus

Answer 20

brown algae (phylum Phaeophyta)
outer surface covered by gelatinous sheath
tips of branches are called conceptacles and may be swollen and contain reproductive structures (oogonia and antheridia)
Reproduces by alternation of generations

Question 21

What is the reproductive cycle of Fucus?

Answer 21

diploid parent has conceptacles on tips of branches, containing oogonia and antheridia
undergo meiosis and then mitosis and sperm/egg formation
gametes fuse in syngamy
Zygote is formed and germinates

Question 22

What are some commercial uses of algae?

Answer 22

brown algae:
kombu (kelp marketed as food)
alginic acid - hydrophilic substance used as emulsifier

red algae:
agar

Question 23

Phylum Rhodophyta

Answer 23

red algae - have red phycobilins in their plastids
warm marine waters
thallus can be attached or free-floating, filamentous or fleshy

Question 24

Porphyra

Answer 24

red algae

“blades” consisting of two layers of cells separated by colloidal material

Question 25

Phylum Bacillariophyta

Answer 25

Diatoms

Question 26

Diatoms

Answer 26

unicellular algae containing multiple pigments; variety of shapes primary link in food chain in ocean due to great numbers, rapid reproduction rates, and photosynthetic abilities hard cell wall made of silicon dioxide, arranged in overlaping halves

Question 27

diatomaceous earth

Answer 27

the silicone dioxide walls of diatoms remain after cell has disintegrated; can accumulate into layers of this

Question 28

Phylum Dinozoa

Answer 28

dinoflagellates all unicellular cellulose plates and two flagella in perpendicular grooves primary produces in ocean and include autotrophic and heterotrophic forms

Question 29

Peridinium

Answer 29

dinoflagellate

Question 30

Ceratium

Answer 30

dinoflagellate

Question 31

Phylum Euglenida

Answer 31

Euglenoids mostly freshwater unicellular algae plastids contain chlorophyll like green algae but cell walls made largely of protein; motile and have two flagella

Question 32

Euglena

Answer 32

Euglenoid; contains chloroplasts and paramylon granules, where food reserves are stored Can be autotrophic, heterotrophic, and saprophytic depending on environment