What are the physiological characteristics of protozoans?
What are the physiological characteristics of protozoans?
Most protozoa have a single nucleus, but some have both a macronucleus and one or more micronuclei. Contractile vacuoles may be present in protozoa to remove excess water, and food vacuoles are often observed. Nutrition and locomotion.
What is an anaerobic protozoan?
Anaerobic protozoans Those eukaryotes that are anaerobic often are either parasites or obligate symbionts of multicellular organisms that have evolved from aerobic ancestors. Trichomonads are a large group of anaerobic parasites. The organism Trichomonas vaginalis causes the sexually transmitted disease trichomoniasis.
Why does Encystment important in protozoans?
During the encystment process, the protozoan cell undergoes a series of changes that considerably reduce the complexity of the organism. For soil-dwelling protozoans the cyst is an important refuge when soil moisture disappears or when soil water becomes frozen.
What is the role of stress in protozoa life cycle?
Thus, the study of stress responses in parasitic protozoa is germane to pathogenesis and transmission. These cysts remain in the host and are responsible for oral transmission of Toxoplasma when the host is preyed upon.
Which is the best description of a microfibril?
A microfibril is a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose. It is usually, but not always, used as a general term in describing the structure of protein fiber, e.g. hair and sperm tail. Its most frequently observed structural pattern is the 9+2 pattern in which two central protofibrils…
How is the nutrition of a protozoa manifested?
The nutrition of protozoa is manifested by following ways (Fig. 10.68): A. Holozoic or Zootrophic or Heterotrophic nutrition, B. Holotrophic or Autotrophic or Phytotrophic nutrition, C. Saprozoic or Saprophytic nutrition, D. Parasitic nutrition and
How are microfibrils synthesized in anisotropically expanding cells?
Anisotropically expanding cells have randomly oriented microfibrils, whereas elongating cells have microfibrils aligned transversely to the axis of elongation. Cellulose microfibrils are synthesized generally by plasma membrane-bound enzymes1,2.
How are microtubules related to the orientation of microfibrils?
The orientation of the cellulose microfibrils is thought to be regulated, in part, by microtubules, as microtubule orientation is parallel to, and correlated with, the orientation of cellulose microfibrils (Hepler and Newcomb, 1964). Moreover, microtubule orientation predicts the orientation of newly deposited cellulose microfibrils.