SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

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1 Exam Name SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Use Figure 20.1 to answer the following question. Figure ) Which enzyme was used to produce the molecule in Figure 20.1? 1) Use the following information to answer the next few questions. A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest. 2) Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate? 2) 3) In recombinant DNA methods, the term vector can refer to 3) 4) The oxygen revolution changed Earthʹs environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere? 4) Use Figure 20.2 to answer the following question. Figure ) Draw a gel representing a plasmid which has restriction sites I and II to create restriction fragments A, B, and C. 5) 6) Why are yeast cells frequently used as hosts for cloning? 6) 7) DNA technology has many medical applications. List some technologies which are not done routinely at present? 7) 8) RNA molecules can both carry genetic information and be catalytic. This supports which proposal about early life forms? 8) 1

2 9) Which of the following factors weaken(s) the hypothesis of abiotic synthesis of organic monomers in early Earthʹs atmosphere? 1. the relatively short time between intense meteor bombardment and the appearance of the first life-forms 2. the lack of experimental evidence that organic monomers can form by abiotic synthesis 3. uncertainty about which gases comprised early Earthʹs atmosphere 9) 10) Which of the following is the correct sequence of events in the origin of life? I. formation of protobionts II. synthesis of organic monomers III. synthesis of organic polymers IV. formation of DNA-based genetic systems 10) 11) Which of the following is a defining characteristic that all protobionts had in common? 11) 12) Approximately how far back in time does the fossil record extend? 12) 13) Fossilized stromatolites are? 13) 14) Which free-living cells were the earliest contributors to the formation of Earthʹs oxidizing atmosphere? 14) 15) Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes? 15) 16) If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old? 16) 17) What kind of chemicals likely made up the first genes on Earth? 17) 18) What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth? 18) 19) What is the enzymatic function of restriction enzymes? 19) 20) Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to 20) 21) What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes. III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA. 21) 2

3 22) Which of critical step has not yet been accomplished by scientists studying the origin of life? 22) 23) How does a bacterial cell protect its own DNA from restriction enzymes? 23) The following questions are based on the observation that several dozen different proteins comprise the prokaryotic flagellum and its attachment to the prokaryotic cell, producing a highly complex structure. 24) In certain motile prokaryotes, dozens of different proteins comprise the motor that powers the prokaryotic flagellum. The motor has a complicated structure, and its various proteins interact to carry out its function. Based on Darwinʹs explanation for the existence of human eyes, how would he probably have explained the existence of such motors? 24) 25) Which enzyme seals the sticky ends of restriction fragments to make recombinant DNA? 25) 26) Which process produces multiple identical copies of a gene for basic research or for large-scale production of a gene product? 26) Use the following information to answer the questions below. A eukaryotic gene has ʺsticky endsʺ produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. 27) Bacteria that contain the plasmid, but not the eukaryotic gene, would grow in which conditions? 27) 28) Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in which conditions? 28) 29) Bacteria that do not take up any plasmids would grow on which media? 29) 30) Which biotechnology separates molecules by movement due to size and electrical charge? 30) 31) In 1997, Dolly the sheep was cloned. Briefly explain how it occurred. 31) 3

4 Use Figure 20.3 to answer the following questions. The DNA profiles below represent four different individuals. Figure ) Which individual could be the child of which two other individuals? Why? 32) 33) Which two are probably siblings? 33) 34) What is generally true of two very closely related species that have diverged from each other quite recently? 34) 35) In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of 35) 36) Which gas was least abundant in Earthʹs early atmosphere, prior to 2 billion years ago? 36) 37) What type of sequence in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme? 37) 38) Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. The biological species is the largest unit of population in which successful reproduction is possible. 38) 39) Bacteria containing recombinant plasmids are often identified by which process? 39) 40) LIst the use/application for DNA ligase, gel electrophoresis, restriction enzymes, and DNA polymerase. What does reverse transcriptase do? 40) 4

5 41) What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4. origin of cyanobacteria 5. origin of fungal-plant symbioses 41) After reading the paragraph, answer the question(s) that follow. Corals belong to phylum Cnidaria. The reefs themselves are made up of millions of polyps, each of which secretes a calcium carbonate skeleton that becomes part of the reef structure. Coral, which are attached to the reef as adults, have free-swimming larvae that develop into new polyps. Corals are actually colorless. The brilliant colors that are visible on the reef come from the zooxanthellae (microscopic algae) that live within their body tissues. The zooxanthellae and corals have a symbiotic relationship in which corals provide carbon dioxide and mineral nutrients (released as wastes from coral digestion) to the zooxanthellae. The zooxanthellae perform photosynthesis. Photosynthesis produces nutrients (in the form of sugars) for the coral and also releases oxygen. This relationship supplements energy from predation and allows corals to survive in clear tropical water, even though these areas have very low nutrient levels. 42) What advantage do free-swimming larvae confer on reef-building corals? 42) 43) Openings which allow gas exchange in most land plants are structures called 43) 44) The majority of plant species today belong to which group? 44) 45) A bilaterally symmetrical, wormlike animal that has a pseudocoelom, a complete digestive tract, and a cuticle could be a member of which one of the following phyla? 45) 46) Animals that are segmented and have jointed appendages and an exoskeleton are members of the phylum 46) 47) Mosses belong to the group of plants known as the 47) 48) Which features is unique to chordates? 48) 49) Which phyla is most closely related to echinoderms? 49) 50) Most adult insects have three major body parts or sections. They are the 50) 51) Which adaptation is a key characteristic of annelids that greatly increases their flexibility and mobility? 51) 52) The most numerous, diverse, and widespread animals are the 52) 53) What is the waxy coating that prevents water loss in plants called? 53) 5

6 54) What type of organism produces penicillin? 54) 55) Identify a unique feature of echinoderms? 55) 56) List the plant groups in order to correctly represent the most likely sequence of the evolution of plants, from earliest to most recent. 56) 57) Two characteristics shared by gymnosperms and angiosperms that are absent from earlier plant groups and represent key adaptations to life on dry land are 57) 58) Which plants has a dominant diploid generation and a seed, but no fruit? 58) 59) The dominant stage of the moss life cycle is the 59) 60) Corn, rice, wheat, fleshy fruits such as apples and berries, and many spices are all produced by which group of plants? 60) 61) Which part of the life cycle does a pollen grain represent? 61) 62) Describe ferns in terms of reproduction and structure. 62) 63) Heterotrophic eukaryotes that digest their food externally and absorb the small molecules are referred to as 63) 64) Identify a structure found in angiosperms but not gymnosperms? 64) 65) The is the protective chamber that houses the ovule and later matures to become the fruit. 65) 66) List characteristics all animals have in common. 66) 67) Most of the animals alive today belong to which general group? 67) 68) A mushroom is what part of the fungi life cycle? 68) 69) While wading in the ocean, you look down into the water and notice an umbrella-shaped, translucent animal. It swims by pulsing its body, and long tentacles trail behind it. One of them brushes your leg. Ouch! You feel a burning sensation where it touched you. To what phylum does this creature probably belong? 69) 70) Name several animals are not included among the Bilateria, a clade of animals with bilateral symmetry at some stage of development? 70) 71) Flatworms (Platyhelminthes) have what kind of symmetry and what kind of body plan? 71) 72) What are coral reefs? 72) 6

7 73) Which animals are not included among the Eumetazoans, which have true tissues? 73) 74) A typical sponge is best described as 74) 75) A dogʹs head is at its end and its belly is its surface. 75) 76) List three or more items which demonstrate radial symmetry? 76) 77) About 95% of all modern plant species 77) 78) Give three animals which display radial symmetry? 78) 79) Animals probably evolved from 79) 80) Name an essential part of most fungal reproductive systems? 80) 81) Threadlike fungal filaments are called 81) 82) The ripened ovary of a flower, which is adapted to disperse seeds, is called a(n) 82) 83) What kind of entity is a lichen? 83) 84) The type of life cycle seen in plants is called 84) 85) The ancestors of land plants were probably that lived in. 85) 86) Label the parts of the flower. 86) 7

8 87) Label the parts of the lobster. Which phyla does this organism belong to? 87) ESSAY. Write your answer in the space provided or on a separate sheet of paper. 88) Use the unlabeled clock diagram below to test your memory of the sequence of key events in the history of life on Earth described in this chapter by labeling the colored bars. As a visual aid to help you study, add labels that represent other significant events discussed in the chapter, such as the origin of prokaryotic cells, the first photosynthetic prokaryotic cells, origin of eukaryotic cells, origin of multicellular organisms, origin of land plants. 8

9 89) Select one example of a biotechnology you have studied in this course. Describe how it works and its applications 90) List and explain four key adaptations that land plants had to overcome in order to be successful on land. 91) Describe the five earliest groups of animals and for each group show how there was a change in symmetry, body plan, and level of organization. For each change, describe how it was a benefit. 9

10 92) Describe the role of the organs that make up the digestive system of this earthworm. 93) Sponges have no muscles and cannot move as a mature organism. They have no nerve cells and cannot sense the environment around them. Why are they considered to be animals? (hint - what characteristics do we use to define animals and is there a way that sponges fulfill them all?) 10