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When diatoms die,their shells fall to the floor of the ocean or lake that they inhabit and form sediments called diatomaceous earth (DE) .Diatoms can be identified by their shells,and different species of diatoms prefer different water temperatures.What information can be gained if scientists take samples of long-existing DE and identify the diatom species that created it?


A) Scientists can decipher evolutionary lineages between diatom species.
B) Scientists can predict future trends in greenhouse gas emissions.
C) Scientists can learn about past climates.
D) Scientists can better understand how wind currents affect water temperature.

E) B) and C)
F) A) and D)

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Plastids that are surrounded by more than two membranes are evidence of


A) evolution from mitochondria.
B) fusion of plastids.
C) origin of the plastids from archaea.
D) secondary endosymbiosis.

E) A) and B)
F) B) and D)

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Which of the following statements support(s) the theory of the endosymbiotic origin of mitochondria and plastids? I.Mitochondria and plastids have circular DNA and replicate by splitting. II.Mitochondria and plastids have ribosomes. III.Mitochondrial and plastid ribosomal RNA sequences are more similar to cytoplasmic ribosomes than to bacterial ones. IV.The inner membranes of plastids and mitochondria have transport proteins homologous to those in bacterial plasma membranes.


A) I only
B) I and II only
C) III only
D) I,II,and IV

E) A) and B)
F) C) and D)

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The life cycle of the malarial parasite,Plasmodium,includes


A) haploid and diploid stages both inside the human host and the mosquito.
B) a haploid stage diploid inside the human host and both haploid and diploid stages in the mosquito.
C) only haploid stages inside the mosquito and diploid states inside liver cells and blood cells of humans.

D) None of the above
E) A) and B)

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Which of the following is the most likely sequence of events,from earliest to most recent,in the evolution of sponges (organisms with many cells that have different functions) ? 1) single-celled eukaryote 2) single-celled prokaryote 3) multicellular eukaryote 4) colonial eukaryote


A) 2,1,4,3
B) 2,1,3,4
C) 1,2,3,4
D) 1,2,4,3

E) B) and C)
F) None of the above

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Which of the following was derived from an ancestral cyanobacterium?


A) chloroplast
B) mitochondrion
C) hydrogenosome
D) mitosome

E) A) and C)
F) C) and D)

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During passage through the large intestine,a trophozoite will often secrete a case around itself,forming a cyst.Cysts contain four haploid nuclei.When cysts "hatch" within a new host,two trophozoites are released.Thus,which of the following must happen within the cyst prior to hatching? 1) meiosis 2) nuclear division 3) S phase 4) binary fission


A) 1 only
B) 1 and 2
C) 2 and 3
D) 2 and 4
E) 2,3,and 4

F) C) and D)
G) A) and B)

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Based on the phylogenetic tree in the figure given below,which of the following statements is correct? Based on the phylogenetic tree in the figure given below,which of the following statements is correct?   A) The most recent common ancestor of Excavata is older than that of SAR. B) The most recent common ancestor of red algae and plants is older than that of nucleariids and fungi. C) The most basal (first to diverge) eukaryotic supergroup cannot be determined. D) Excavata is the most basal eukaryotic supergroup.


A) The most recent common ancestor of Excavata is older than that of SAR.
B) The most recent common ancestor of red algae and plants is older than that of nucleariids and fungi.
C) The most basal (first to diverge) eukaryotic supergroup cannot be determined.
D) Excavata is the most basal eukaryotic supergroup.

E) A) and D)
F) None of the above

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Unlike most excavates,Giardia trophozoites have no oral groove and are unable to form food vacuoles.Thus,we should expect its nutrition (mostly glucose) to come from


A) its mitosomes.
B) endosymbiotic cyanobacteria.
C) the ventral disk by which it adheres to the intestinal lining.
D) osmosis involving aquaporins (proteins that transport water across cell membranes) .
E) plasma membrane proteins that are transporters or pumps.

F) C) and D)
G) A) and B)

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The closest living relative of P.chromatophora is the heterotroph P.ovalis.What type of evidence permits biologists to make this claim about relatedness?


A) morphological
B) ecological
C) biochemical
D) genetic
E) fossil

F) C) and D)
G) A) and C)

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A crucial photosynthetic gene of the cyanobacterium that gave rise to the cyanelle is called psaE.This gene is present in the nuclear genome of the cercozoan but is not in the genome of the cyanelle.This is evidence of


A) reciprocal mutations in the cyanelle and nuclear genomes.
B) horizontal gene transfer from bacterium to eukaryotes.
C) genetic recombination involving a protist and an archaean.
D) the origin of photosynthesis in protists.
E) transduction by a phage that infects both prokaryotes and eukaryotes.

F) A) and B)
G) C) and D)

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In a synthetic biology experiment,you are given a task to design a new species of aquatic protist.Your design should account for the following characteristics: 1) The protist functions as a primary producer. 2) It cannot swim on its own. 3) It must stay in well-lit surface waters. 4) It must be resistant to physical damage from wave action. Based on these criteria,you decide to model your creation after a(n)


A) diatom.
B) dinoflagellate.
C) apicomplexan.
D) red alga.
E) radiolarian.

F) A) and D)
G) C) and D)

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Which group is incorrectly paired with its description?


A) diatoms-important producers in aquatic communities
B) red algae-acquired plastids by secondary endosymbiosis
C) apicomplexans-parasites with intricate life cycles
D) diplomonads-protists with modified mitochondria

E) A) and D)
F) B) and D)

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You are given four test tubes,each containing an unknown protist.Your task is to read the following description and match these four protists to the correct test tube. When red and blue light are shone on the tubes,oxygen bubbles accumulate on the inside of test tubes 1 and 2.Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans.Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica.Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each.Microscopic analysis of the contents in test tube 4 reveals thousands of cilia on the surface of the organism.Please use the following information to answer the questions below. -Test tube 1 contains


A) Paramecium.
B) Navicula (diatom) .
C) Pfiesteria (dinoflagellate) .
D) Plasmodium.

E) A) and D)
F) A) and C)

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Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because


A) the products of photosynthesis could not be metabolized without mitochondrial enzymes.
B) all eukaryotes have mitochondria (or their remnants) ,whereas many eukaryotes do not have plastids.
C) mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.
D) without mitochondrial CO2 production,photosynthesis could not occur.

E) A) and B)
F) B) and D)

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You are given four test tubes,each containing an unknown protist.Your task is to read the following description and match these four protists to the correct test tube. When red and blue light are shone on the tubes,oxygen bubbles accumulate on the inside of test tubes 1 and 2.Chemical analysis of test tube 1 indicates the presence of a chemical that is toxic to fish and humans.Chemical analysis of test tube 2 indicates the presence of substantial amounts of silica.Microscopic analysis of organisms in test tube 3 reveals the presence of an apicoplast in each.Microscopic analysis of the contents in test tube 4 reveals thousands of cilia on the surface of the organism.Please use the following information to answer the questions below. -Test tube 4 contains


A) Paramecium.
B) Navicula (diatom) .
C) Pfiesteria (dinoflagellate) .
D) Plasmodium.

E) A) and B)
F) None of the above

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The evolution of multicellularity in animals has primarily occurred by


A) changing how existing genes are used.
B) deleting many old genes.
C) producing many new genes.
D) deleting many old chromosomes.

E) B) and D)
F) A) and B)

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The closest living relative of P.chromatophora is the heterotroph P.ovalis.P.ovalis uses threadlike pseudopods to capture its prey,which it digests internally.Which of the following,if observed,would be the best reason for relabeling P.chromatophora as a mixotroph?


A) a threadlike pseudopod
B) a vacuole with food inside
C) a secretory vesicle
D) a contractile vacuole

E) A) and D)
F) B) and D)

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A snail-like,coiled,porous test (shell) of calcium carbonate is characteristic of which group?


A) diatoms
B) foraminiferans
C) red algae
D) cercozoans

E) A) and C)
F) None of the above

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Comparisons of choanoflagellate and animal genome sequences tell us that key steps in the transition to multicellularity in animals involved new ways of using proteins or parts of proteins that were encoded by genes found in


A) multicellular eukaryotes.
B) unicellular protists.
C) unicellular bacteria.
D) unicellular archeae.

E) A) and B)
F) A) and C)

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