Zoo-Lab (Sem-1) - Exercise 9: Protozoa

protozoans

single-celled animals under Kingdom Protista; mostly microscopic

Paramecium; Amoeba; Euglena; Trypanosoma; Balantidium; Vorticella

examples of protozoans

Paramecium sp.

slipper-shaped; swims with spiral or rotary movement; body is a mass of dense protoplasm

micronucleus

part of a Paramecium; a smaller isolated nuclear structure separated from the main nucleus

macronucleus

part of a Paramecium; the larger type of nucleus in ciliates

anterior

narrower and rounded end of a Paramecium

posterior

wider and pointed end of a Paramecium

cilia

hair-like projections; structures for locomotion

peristome

funnel-like bearing cilia lined in rows from anterior left to posterior right, slightly oblique

food vacuoles

sometimes contain solid particles; scattered inside the body of Paramecium; more numerous in the posterior portion than in the anterior end

contractile vacuoles

two clear vacuoles, one in the anterior end and another in the posterior end, appear and disappear at intervals

binary fission

asexual reproduction by a separation of the body into two new bodies; an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA

early fission

elongation of the micronucleus and macronucleus

middle fission

deepening of constriction

late fission

deepening of constriction result in the pinching off of the Paramecium into two daughter paramecia

conjugation

sexual reproduction; two paramecia joined at their oval grooves and swim around

trichocysts

membrane-bound extrusomes with a predatory or protective role