bio lab chapter 3 protists

protista

a paraphyletic taxon defined by exclusion and contains some, but not all, descendants of a common eukaryotic ancestor. this includes non-animals, non-fungi, and non-plant eukaryotes such as alveolates, rhizarians, and choanoflagellates

protozoa

animal-like heterotrophic unicellular organisms that have the ability to move in their habitat

algae

commonly used term to describe microscopic photosynthetic eukaryotes. some are unicellular while some are multicellular but lack highly differentiated structures

brown algae

live almost exclusively underwater. have chlorophyll a but not chlorophyll b as photosynthetic pigments

red algae

mostly multicellular and marine. along with chlorophyll a and chlorophyll b, they also have phycoerythrin which gives them the red pigment by absorbing blue light

green algae

unicellular, colonial, or multicellular. may live in freshwater, moist soils, or marine environments

• closest to lands plants because:

• they both use chlorophyll b as one of their photosynthetic pigments

• both have cellulose in their cell wall

• both store photosynthetic products in the form of starch

• multicellular green algae such as sea lettuce reproduce sexually, alternating between haploid gametophyte and diploid sporophyte stages

• land plants and green algae are grouped together as a taxon called green plants

land plants

have protected embryo, cuticle, gametangia, thick spore walls, and other features that help their life on land even though some are aquatic

pseudopods

feet like structures formed by temporarily extended cytoplasmic projections

• locomotion for amoebas

cilia

small hair-like projections

• locomotion for paramecia

flagella

long, whip-like projection

• locomotion for trypanosoma and euglena

positive phototaxis

moving towards light to facilitate photosynthesis using the light sensitive stigma (eyespots)

phagocytosis

feeding by surrounding pseudopods around food particles and forming food vacuoles to bring them inside the cytoplasm

binary fission

one fully grown organism divides into two daughter cells, forming two new identical organisms

amoeba

• unicellular protist that uses pseudopods for locomotion

• pseudopods also used for feeding by phagocytosis to produce food vacuoles

• uses contractile vacuoles to get rid of excess water

• reproduces via binary fission (asexual)

paramecium

• unicellular protist that moves by beating its cilia

• usually has one macronucleus and several micronuclei

• transverse binary fission

• conjugation

transverse binary fission

asexual reproductive process where the organism splits along the short axis of the organism

conjugation

sexual reproduction which is a genetic recombination process that involves temporary fusion of two organisms, exchange of micronuclear materials, and reorganization of macronuclear materials

congo red

pH indicator

• when content is neutral or slightly alkaline it appears red

• when content is acidic it appears green

• when the food vacuole is first formed it is a bright red-orange

• along the way it turns blue-green

• eventually waste products are eliminated through the anal pore

euglena

• unicellular protist that has a resilient pellicle layer outside its cell membrane and moves around with its flagella

• can be autotrophic or heterotrophic

• has chloroplasts to absorb sunlight to conduct photosynthesis

• has a stigma or eyespot that senses light, which allows the organism to move toward (positive phototaxis) or away from (negative phototaxis) to maximize light for photosynthesis and minimize photo damage

holdfast

root-like structure that anchors the algae

stipe

which is a stem-like structure

blade

leaf-like structure

pneumatocysts

gas-filled floats for buoyancy

chlamydomonas

• unicellular green algae commonly found in damp soil, lakes, and ditches

• egg shaped and moves by beating its flagella

• autotrophic with a large cup shaped chloroplast

• has a pyrenoid, a protein body that functions in starch formation

• also has a stigma or eyespot that senses light

volvox

• spherical autotrophic colonial protist

• reproduces sexually and asexually

spirogyra

free-floating freshwater multicellular green algae

reproduces asexually via fragmentation