Zoology: Lesson 1, Unicellular Organisms

Outer plasma membrane

adhesion of the cell surface to the substratum or nutrient particles and aid in ingestion of food

ectoplasm

thin and outer layer of the cytoplasm (stiff)

endoplasm

inner and more fluid layer of the cytoplasm

Hyaline cortex

"glassy rind" ; clear ectoplasm

Pseudopodia

"false feet" ; ameba creeps an extending arm forward, then the rest of the cell will follow

Hyaline cap

the advancing end of the pseudopodium (the one that extends out of the ameba to move)

Actin and Myosin

major proteins in animal muscles that also occur in unicells

Filopodium

actin fibers that push against the plasma membrane to extend it as a narrow pointed pseudopodium

Lobopodium

actin MESHWORK that extends the plasma membrane as a broad and blund pseudopodium

Ameboid Movement

the result of the alternate rapid assembly and disassembly of actin fibers and meshworks

Food Vacuoles

particles of food surrounded by water and enclosed in a membrane

Phagocytes

foreign particles (AFAM!)

Phagocytosis

[phago: to eat; kyotos: vessel = to eat vessel] encircling the prey by pseudopodia

Hydrolic enzymes

digest the contents of the phagocyte

Lysosomes

merge with the food vacuole

Pinocytosis

[phino: to drink; kyotos: vessel = to drink vessel] taking in of fluid and minute food particles by cells

Contractile vacuole

Organelle that gradually increases in size by accumulation of fluid, then ruptures, then disappears

Nucleus

found at the center; disc-shaped with an indent; refractive to light; carried along by cytoplasm

Green-like color

Due to the presence of a chloroplast and chlorophyll

Flagellum

Uses flagellum to move and it emerges from the reservoir in the anterior end

forward and corkscrew movement

Euglenoid movement

the cell undergoes a drastic change in shape; when it stops swimming; wormlike contractions

Pellicle

outer skin; a protective but flexible layer that is secreted by the ectoplasm and surrounds the endoplasm

Stigma

eyespot; reddish pigment spot that shades a swollen basal area of the flagellum; is thought to be light-sensitive

Holophytic

capable of synthesizing their food from inorganic molecules, esp by photosynthesis.

Paramylon

a carbohydrate similar to starch that is stored in the euglena after photosynthesis

Longitudinal fission

a type of asexual reproduction wherein happens when the organism is free or when it is in the encysted state

Multicellular

sexual reproduction must be limited to particular cells within the group (specific cells only can reproduce)

Unicellular

Volvox is still unicellular because ALL of its cells can reproduce sexually

Zooids

one celled individuals

Protoplasmic strands

connects each zooid in the colony

Somatic cells

make up most of the colony; handles nutrition, locomotion, and response to stimuli

Macrogametes

egg cells of volvox

Microgametes

sperm cells of volvox

Spring/Summer season (warm)

volvox reproduces asexually; will produce/develop sex cells; will then reproduce sexually

Fall/Winter

Encystment of the volvox after reproducing

Obligate heterotrophs

lack chlorophyll and obtain their organic and inorganic requirements from the environment

Osmotrophic

absorbs nutrients directlt from the surrounding blood or bodily fluid

Diseases caused

Sleeping sickness

Sporogony

Spore formation, often seen in zygotes of apicomplexans

Schizogony

a means of spreading the population within the host and this is followed by sporongony

Diseases caused by plasmodium

Malaria

Trophozoites

once merozoites become adults in the red blood cell

Oral Groove

mouth of the paramecium

Cytostome

Prosterior end of the oral groove

Cytopharynx

gullet; an extending canal from the mouth into the body

Pellicle

skin of the paramecium; has 2 parts - ecto and endoplasm

Ciliary action

propels the unicell forward; like an oar-boat

Trichocysts

repel predators

Cytoproct

temporary opening where indigestible food is discharged

Taxis

type of response

phototaxis

response to light rays

Thigmotaxis

response to contact

geotaxis

response to gravity