Compare and contrast archaea and bacteria, with particular attention to the features that lead to their placement in separate taxa
What will be an ideal response?
Bacterial cell walls are composed of peptidoglycan, whereas archaeal cell walls are composed of a variety of carbohydrate forms but never peptidoglycan. The flagella of the two groups of prokaryotes have several differences, including size, manner of assembly, and function. Although both have fimbriae, archaea have a distinctive attachment structure called a hamus that is somewhat like a barbed grappling hook. Bacterial cytoplasmic membranes may contain hopanoids, archaeal cytoplasmic membranes do not. The ribosomes of archaea and bacteria are of similar size, but some ribosomal components of archaea are more like those of eukaryotic ribosomes than those of bacteria. RNA metabolism in the two prokaryotic groups differs, and the archaeal genetic code is more like that of eukaryotes than that of bacteria. Archaeal phospholipids are different from bacterial and eukaryotic phospholipids in that the glycerol is a stereoisomer, the linkages are ether instead of ester between hydrocarbon chains and glycerol, the hydrocarbon chains are isoprene chains rather than fatty acids, which are branched rather than linear, as the fatty acids are.
Bloom's Taxonomy: Analysis
Section: Cytoplasm of Archaea
Learning Outcome: 3.24, 3.25, 3.26, 3.27, 3.28, 3.29
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Mutation rates are similar in Bacteria and Archaea, yet certain stressful conditions mutation rates increase. Why is the mutation rate not constant and close to zero all of the time?
A) Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival. B) Microorganisms carefully control the mutation rate of their DNA to match the environmental conditions and maximize evolution. C) The increased mutation rate under stressful conditions is an indication that the microorganisms can no longer replicate their DNA properly and are about to die. D) Constant mutation rates would halt evolution completely.
The part of the Drosophila zygote with high bicoid concentration will
A. become the anterior region of the embryo B. become the region of the embryo that has a spiracle C. become the tail region of the embryo D. become the segment that will have wings E. become the segments that will have legs
About twelve to twenty-four hours after the previous meal, a person's blood-sugar level normally varies from 60 to 90
milligrams per 100 milliliters of blood, though it may rise to 130 mg/100 ml after meals high in carbohydrates. That the blood-sugar level is maintained within a fairly narrow range despite uneven intake of sugar is due to the body's ability to carry out
a. adaptation. b. inheritance. c. metabolism. d. homeostasis.
e. evolution.occurs within ___ minutes to allergen. (immunological disorders)
Fill in the blank(s) with the appropriate word(s).