Exam 25: The Origin and Diversification of Eukaryotes

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

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?

The evolution of multicellularity in animals has primarily occurred by

The life cycle of the malarial parasite,Plasmodium,includes

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

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 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

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

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.

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

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

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

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

Based on the phylogenetic tree in the figure given below,which of the following statements is correct?

Which group is incorrectly paired with its description?

Which of the following was derived from an ancestral cyanobacterium?

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

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)

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