Chapter 27 (Homework) – Flashcards
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Which group was not described by Woese's tree of life analysis? a) Archaea b) Eukarya c) Prokarya d) Bacteria
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c) Prokarya
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What characteristics were used to classify organisms BEFORE Woese's tree of life analysis? a) presence of a membrane-bound nucleus b) composition of the cell wall c) differences in ribosomal RNA sequences d) number of cells in the organsim
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a) presence of a membrane-bound nucleus Before the tree of life analysis, organisms were classified as: (1) prokaryotes if they lacked a membrane-bound nucleus or (2) eukaryotes if they possessed a membrane-bound nucleus
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True or false? Data showing that the Bacteria were the first lineage to diverge from the common ancestor of all living organisms suggest that the Archaea and Eukarya are more closely related to each other than they are to Bacteria.
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True. The tree indicates that the common ancestor for Eukarya and Archaea is more recent than the common ancestor for all (3) domains. Eukarya are therefore more closely related to the Archaea than is to the Bacteria.
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Which of the following statements about phylogenetic trees is true? a) a paraphyletic group consists of a common ancestor and some of its descendants b) a praaphyletic group has not experienced lateral gene transfer c) a parphyletic group consists of an ancestral population and all of its descendants d) a monophyletic group consists of a common ancestor and some of its descendats
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a) a paraphyletic group consists of a common ancestor and some of its descendants. monophyletic - common ancestor and ALL of its descendents paraphyletic - common ancestor and SOME of its descendents *The common characteristics of a paraphyletic group may have risen from lateral gene transfer to SOME, but NOT ALL lineages.
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Which molecule did Carl Woese study to produce his tree of life? a) ribosomal RNA b) DNA c) Messenger RNA d) Ribosome
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a) ribosomal RNA Ribosomal RNA (rRNA) was the molecule used to produce Woese's phylogeny because: 1) it evolves slowly 2) is critical to the function of the ribosome, which serves the same function in all (3) domains in the tree of life.
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What is lateral gene transfer? a) Inheritance of a gene through mitosis b) inheritance of a gene from a parent c) physical transfer of a gene from a species in one lineage to a species in another lineage d) inheritance of a gene through meiosis
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c) physical transfer of a gene from a species in one lineage to a species in another lineage Lateral gene transfer = the physical transfer of a gene btwn distantly related lineages
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How does the lg. amt of genetic variation observed in prokayotes arise? a) the mutation rate in prokaryotes is much higher than in eukarotes b) they have extremely short generation times and large populations c) they can exchange DNA with many types of prokayotes by way of horizontal gene transfer d) they have a relatively small genome e) b and c are correct
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e) b and c are correct. The short generation times and large population sizes in most prokaryotic species, coupled with their ability to exchange genes, helps to increase genetic variability beyond what we could expect in asexually reproducing organisms.
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Which two structures play a role in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules 2. endospores 3. fimbriae 4. plasmids 5. flagella
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1. and 3. The cell wall of many prokaryotes is surrounded by a sticky layer of polysaccharides or protein. This layer is called a capsule. Some prokaryotes stick to their substrate or to one another by means of hair-like appendages called fimbriae (sing. fimbria)
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Prokaryotes essential genetic information is located in the: a) nucleosome b) nucleoid c) plasmids d) nucleolus e) exospore
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b) Nucleoid - comp. of DNA
