Problem :
Compare the processes of phagocytosis and pinocytosis.
Phagocytosis is used to bring large particles into the cell and involves a
bulging out of part of the cell membrane. Pinocytosis is used to bring in small
particles and liquids and involves the pinching off of an invagination of the
cell membrane.
Problem :
Describe the method of transmission of African Sleeping Sickness.
The protozoa responsible for the sleeping sickness,
Trypanosoma
gambiense, lives in the blood of animals. When an infected animal is bitten
by a tsetse fly, the trypanosoma are sucked into the fly's intestines. Here they
undergo a physiological change that allows them to invade the salivary glands of
the fly. Every animal that is bitten by this fly now receives an injection of
Trypanosoma gambiense.
Problem :
Describe the eukaryotic cilia and name two functions they perform.
Eukaryotic cilia are similar in internal structure to flagella, but are much
shorter and hair-like. They can be connected at the base to contractile fibers
that allow them to beat in fixed patters. Cilia may be used for locomotion or to
sweep food particles toward the oral groove.
Problem :
Describe the process of conjugation and distinguish between the haploid and
diploid phases.
Conjugation begins when individuals of opposite mating types meet, the adhere to
each other at the oral groove. The micronuclei then divide meiotically,
producing four haploid nuclei each. All but one nucleus from each paramecium
disintegrate. The macronucleus also disintegrates, leaving each cell with one
haploid micronucleus. These remaining nuclei then divide mitotically and the two
cells swap copies of their nuclei. The cells separate and the haploid nuclei
fuse, leaving each cell with a new diploid micronucleus. To form a new
macronucleus, the micronucleus divides several times and the resulting nuclei
develop into a macronucleus.
Problem :
Describe amebiod movement.
Helped by filaments of a structural protein called actin, the cytoplasm of a
cell flows beneath the cell membrane into new pseudopods, causing the cell to
move in a given direction.
