Microbiology Fundamentals: A Clinical
Approach, 2nd ed. by Cowan Chapter 4
Last Common Ancestor Correct Answer- Precursor cell to prokaryotes &
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eukaryotes
Neither prokaryotic or eukaryotic
The more complex cell type most likely emerged when a LCA cell engulfed
smaller prokaryotic cells & coexisted with them
History of Eukaryotes Correct Answer- First primitive eukaryotes were probably
single-celled & independent
Cells later began to aggregate & form colonies
Cells became specialized within colonies
Complex organisms later evolved and individual cells lost the ability to survive on
their own
Disease-causing eukaryotes Correct Answer- Protozoa, fungi, & helminths
Theory of Endosymbiosis Correct Answer- One prokaryote engulfs another
Symbiotic relationship allows for the development of organelles
Engulfment of photosynthesis bacteria resulted in organelle chloroplasts
Over time the cells became further specialized & created organs
Cell Movement Correct Answer- Motility allows microorganisms to move toward
nutrients & positive stimuli and away from harmful substances & stimuli
Locomotion via cilia & flagella is common in protozoa, many algae, and a few
fungal & animal cells
Eukaryotic flagella v. Prokaryotic flagella Correct Answer- Eukaryotic flagellum
10x thicker
Covered by extension of cell membrane
Long, sheathed cylinder containing regularly spaced microtubules in a 9+2
arrangement
Microbuses slide past each other creating a whipping emoting that requires
expenditure of energy
Cilia Correct Answer- Similar in structure to flagella, but are shorter & more
numerous
Back & forth beating in oar-like strokes instead of propeller motion like flagella
Only found in single group of protozoa and in certain animal cells (trachea,
fallopian tubes)
Occur all over the cell surface
Also function as feeding & filtering structures
Glycocalyx Correct Answer- Outermost layer that comes into direct contact with
the environment
Usually composed of polysaccharides & appears as a network of fibers, a slime
layer, or a capsule
Functions: protection, adherence to surfaces, reception of signals from another
cells & the environment
Cytoplasmic membrane Correct Answer- Typical bilayer of phospholipids in which
protein molecules are embedded
Contain sterols of various kinds
Serves as selectively permeable barrier
Relative rigidity gives stability to membrane [Show Less]