Biology Exam 2 Tag TAMU Questions and Answers correct

Biology Exam 2 Tag TAMU Questions and Answers correct In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of amino acids What was thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? I. Origin of mitochondria II. Origin of multicellular eukaryotes III. Origin of chloroplasts IV. Origin of cyanobacteria V. Origin of fungal plant symbioses IV, I, III, II, V The first genes on Earth were probably auto-catalytic RNA molecules Who discovered ribozymes? Cech and Altman Although no one will ever find a remnant of the last universal common ancestor of all life, we can infer that it had one property. What is that? It used the same genetic code to translate RNA sequences into proteins as modern cells do. In bacteria, the main source of genetic variation is Mutation Which of the following scenarios represent horizontal gene transfer? (1) Acquisition of the F plasmid by an E. coli cell from another E. coli cell (2) The primary endosymbiotic event that resulted in capture of the mitochondrial precursor by a eukaryotic cell (3) A cell inheriting a copy of a gene that was duplicated in the parental generation (4) Fusion of two haploid gametes to form a diploid zygote Both 1 and 2 *horizontal transfer is anything except parent to offspring This structure differed in thickness and peptidoglycan content in gram negative and gram positive bacteria Cell wall Which of the following traits do archaea and bacteria share? I. Histones II. The presence of a plasma membrane III. Lack of a nuclear envelope IV. Identical rRNA sequence II and III only Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? I. Capsules II. Endospores III. Fimbriae IV. Plasmids V. Flagella I and III Which of the following requires ATP to function, and permits some species to respond to taxes (plural of taxis)? Flagellum In general, how much more volume does a typical eukaryotic cell contain compared to a typical prokaryotic cell? 1,000 times more Which of the following is false about gram-negative bacteria? a) Their chromosomes consist of circular DNA associated with a few proteins b) Penicillin is ineffective against them c) The outermost layer of their cell wall is composed of peptidoglycan d) They often possess an outer membrane contains toxic lipopolysaccharides e) Erythromycin has some effect on them because it targets ribosomes and not cell wall synthesis c) The outermost layer of their cell wall is composed of peptidoglycan Penicillin is an antibiotic that inhibits enzymes from catalyzing the synthesis of peptidoglycan, so which prokaryotes should be most vulnerable to inhibition by penicillin? Gram-positive bacteria Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true? They are subject to lysis in hypotonic conditions Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? genetic characteristics such as ribosomal RNA sequences Which statement about the genomes of prokaryotes is correct? The prokaryotic chromosome is not contained within a nucleus, but rather is found at the nucleoid region Plant-like photosynthesis that releases O2 occurs in Cyanobacteria The thermoacidophile, Sulfolobus acidocaldarius, lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species? 1. It is a bacterium. 2. It is an archaean. 3. The optimal pH of its enzymes will lie above pH 7. 4. The optimal pH of its enzymes will lie below pH 7. 5. It could inhabit certain hydrothermal springs. 6. It could inhabit alkaline hot springs. II, IV, and V Which of these are responsible for the high levels of O2 in the Earth's atmosphere? Photoautotrophs Which of the following obtain energy by oxidizing inorganic substance; energy that is used, in part, to fix CO2? Chemoautotrophs Which of the following are responsible for many human diseases? Parasitic chemoheterotrophs The process of nitrogen fixation Converts atmospheric dinitrogen into forms such as ammonia and nitrate that can be used by cells What unusual feature does the protists Giardia intestinalis have? It is an anaerobic eukaryote because its mitochondria has become reduced and non-functional A marine organism that produces a potent neurotoxins that cause extensive fish kill and shellfish contamination, which if ingested by humans, may be fatal: Dinoflagellates (red tide) The White Cliffs of Dover and the Pyramids of Egypt represent massive accusations of the remains of which group of protists? Foraminiferans (CaCO3) All of the following are unicellular protists that cause human disease except one Which name listed does NOT cause human disease? a) spirogyra b) plasmodium c) giardia lamblia d) trichomonas vaginalis e) trypanosoma a) spirogyra Dr. Marinus collects a large specimen of Laminar on a recent field trip to the coast and identifies it as a phaeophyte. The specimen has a distinct thallus with a holdfast. Which of the following CANNOT be true about this specimen? It is a red alga In a stage of its life cycle this organism exists as a single mass of cytoplasm containing diploid nuclei undivided by a cell membrane Plasmodial slime mold Which of the following correctly pairs a protist with one of its characteristics? Ciliate- macronuclei and micronuclei The figure to the right illustrates a process of involving the temporary fusion of two paramecium individuals. What is the purpose of this process? exchange of haploid micronuclei You are an oceanographer studying plankton in the Gulf of Mexico. You find microscopic, unicellular eukaryotes that have reddish-brown pigment and two flagella working perpendicular to each other. The flagellar movement makes the cells whirl and spin like a top under the light microscope. The BEST guess at the identification of this organism is Dinoflagellate The shells in the figure to the right are primary calcium carbonate and have tiny pores for the extension of pseudopodia. They were made by unicellular foraminiferans How would the chief hypothesis concerning the origin of the ER and Golgi apparatus be described? Infolding of the plasma membrane The chloroplasts of land plants are though to have been derived according to which evolutionary sequence? Cyanobacteria- green algae- land plants Which taxon of eukaryotic organisms is thought to be directly ancestral to the plant kingdom? A) golden algae B) radiolarians C) foraminiferans D) apicomplexans E) green algae Green algae The chlorophyte Volvox lives as a large hollow globe of cells floating in fresh water habitats. Some of the cells have specialized functions at different times, but any cell can independently live on its own. Given this information, choose the list below in which ALL the terms apply correctly to Volvox. Photoautotrophic, colonial, planktonic In fungi, plasmogamy and karyogamy are equivalent to ______ in animals fertilization Which of these is considered most similar to the common ancestor of all fungi: Chytridiomycota Lichens are best described as A mutualistic relationship of single-celled autotrophs and fungi If there were no mycorrhizae, then which of the following would be true? Most vascular plants would be stunted in their growth What is the primary role of a mushroom's underground mycelium? Absorbing nutrients Members of this phylum produce two kinds of haploid spores, one kind being asexually produced conidia: Ascomycota Which of the following supports the argument that viruses are nonliving? They are not cellular Viruses ______ use the host cell to copy themselves and make viral proteins What is the main structural difference between enveloped and nonenveloped viruses? Enveloped viruses have a phospholipid membrane outside their capsid, whereas non enveloped viruses do not have a phospholipid membrane The host range of a virus is determined by the proteins on its surface and that of the host Which of the following accounts for someone who has had regular herpes virus-mediated cold sore or genital sore flare ups? Copies of the herpesvirus genome permanently maintained in host nuclei Which of the following is characteristic of the lytic cycle? A large number of phages are released at a time Which viruses have single-stranded RNA that acts as a template for DNA synthesis? Retroviruses What is the function of reverse transcriptase in retroviruses? It uses vital RNA as a template for DNA synthesis Each choose below gives two events in Earth's history. Choose the one answer in which the first listed event occurred earlier in Earth's history than the second event. Atmosphere because aerobic, first eukaryotes Which gas is thought to be one of the least abundant in Earth's atmosphere, prior to 2 billion years ago? O2 Who synthesized organic monomers in an apparatus designed to stimulate early Earth's conditions? Miller and Urey Which of the following is the correct sequence of these 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 II, III, I, IV Approximately how far back in time does the fossil record extend? 3,500,000,000 If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (for example, lava, volcanic ash) nearby, then it should be Difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of ingenious rock Which of the following statements is false? The presence of cholesterol in fossil is taken as evidence of the generation of prokaryotes from protobionts What is the difference between Gram-negative bacteria and Gram-positive bacteria? Gram-positive bacteria will have thicker cell walls Penicillin will kill most bacteria, but it will not kill any archaea. Why not? Because archaea and bacteria have different kinds of cell walls Suppose bacterium suffered a mutation that greatly reduced its ability to form fimbriae. What effect would this mutation likely have on the cell and its descendants? These cells would have difficulty attaching to surfaces and causing biofilms Suppose you discovered a new type of prokaryotic cell. Which of the following would be most useful to help you determine whether it belonged to bacteria or archaea? Cell membrane In a bacterium that possess antibiotic resistance and the potential to persist through very adverse conditions, such as freezing drying, or high temperatures, DNA should be located within, or be part of, which structures? I. Nucleoid region II. Flagellum III. Endospore IV. Fimbriae V. Plasmids I, III, and V What happens in the Rhizobium/legume interaction The bacterium converts atmospheric nitrogen into a form plants can use in return for sugars and other nutrients from the plant How does the endosymbiotic relationship between Rhizobium species and legumes differ from endosymbiotic relationships between plants and chloroplasts? Rhizobia not inherited from the parents must be re-acquired each generation Which kingdom has been replaced with two domains? Monera If this structure connects the cytoplasm of two bacteria, one of these cells may gain new genetic material. Sex pilus Which of these uses light energy to generate ATP but do not release O2? Photoheterotrophs Which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments? Extreme halophiles Which of the statements about Domain Archaea is false? The highly heat stable enzymes used in polymerase chain reactions (PCR) were isolated from a halophile ^not true, they were isolated from a thermophile A prokaryote living in superheated water near deep-sea hydrothermal vents would most likely have the same kind of RNA polymerase and initiator codes as eukaryotes *to aid in survival Mitochondria are descended from alpha proteobacteria. They are no longer able to live independently because many of the genes on their chromosome are now located in the nuclear genome. What phenomenon accounts for this movement of genes? Horizontal gene transfer In the process of bacterial conjugation, All of the above: a) the recipient cell, but not the donor cell, has new genetic transformation b) DNA transfer is only in one direction, from F+ to F- c) the bacterium with the F factor contracts the sex plus (mating bridge) d) chromosomal DNA may be transferred through the mating bridge to the recipient cell Purple-sulfur bacteria use the energy of light to split H2S, releasing elemental sulfur plus electrons that are used to reduce CO2 to simple sugars. This mode of nutrition is most similar to that of Cyanobacteria *Photosynthesis Plastids that are surrounded by more than 2 membranes are evidence of Secondary endosymbiosis According to the serial endosymbiosis theory, what sequence of events led to the ancestral photosynthetic eukaryote? 1. Photosynthetic prokaryote is engulfed by the cell 2. The cell's plasma membrane folds inward to form nuclear membrane and ER 3. Increase the cell size 4. Aerobic heterotrophic prokaryote is engulfed by the cell 2, 3, 4, 1