Bio Exam 3

Explain how is it possible that the chloroplasts of Euglena (Euglenozoa) and green alga (Chlorophyta) are very similar, yet they don't share a common ancestor who has chloroplasts? a. Euglena must have acquired its chloroplasts by secondary endosymbiosis from a green alga. b. Euglena and green alga must share a recent common ancestor with chloroplasts. c. Euglenozoa and Chloroplast form a monopheltic group, indicating they share their traits from common descent. d. Euglena must have acquired its cholorplasts by doing endosymbiosis with a different photosynthetic prokaryote.

Euglena must have acquired its chloroplasts by secondary endosymbiosis from a green alga.

Select all of the following that provide evidence about the support to the Theory of Endosymbiosis a. the DNA of chloroplasts and mitochondria is very similar to that of other free-living prokaryotes. b. chloroplasts and mitochondria are enclosed in a double membrane c. chloroplast and mitochondria divide by a process that closely resembles binary fission. d. chloroplasts and mitochondria have their own DNA. e. chloroplasts and mitochondria can be made by any eukaryotic cell anew

a. the DNA of chloroplasts and mitochondria is very similar to that of other free-living prokaryotes. b. chloroplasts and mitochondria are enclosed in a double membrane c. chloroplast and mitochondria divide by a process that closely resembles binary fission. d. chloroplasts and mitochondria have their own DNA.

Protists are seen as the bridge between unicellular organisms and multicellular ones. Which of the following support this idea? Select all that apply. a. cells in protistan colonies may have different morphologies and duties. b. some protists lack mitochondria, thus demonstrating that they are the most ancestral. c. Protists can form colonies with interdependence.

a; c

Photosynthetic protists are very important because: (select all that apply) a. they form a symbiosis with organisms such as corals that are fundamental to the ecosystem b. they serve as shelter for large animals such as fish and sharks c. as primary producers, they feed many animals in the food web directly and indirectly d. they are an important source of O2 and capture carbon dioxide. e. they are important source of CO2 contributing to global warming.

a;c;d

What ecological roles can protist have? Select all that apply? a. predators b. mutualistic c. parasitic d. scavangers e. photosynthetizers

all of the above

The protistan Paulinella is has a photosynthetic plastid called a chromatophore. Chromatophores have a peptidoglycan membrane and their DNA is more closely related to cyanobacteria than to chloroplasts (Fig. 25.18). Based on this information, what is the possible origin of the chromatophore?

it is derived from a prokaryote that was engulfed by the ancestor of Paulinella

Which of these statements is true about the evolution of multicellularity in eukaryotes?

it occurred independently multiple times in several eukaryotic lineages.

Which of the groups listed on the tree above descended from an ancestral protist but are not considered protists? Select three (3) a. land plants b. brown algae c. animals d. green algae e. slime mold f. fungi

land plants; animals; fungi

Protists are very diverse. Almost any unicellular eukaryote is considered a protest. However, plants, fungi and animals evolved from ancient protists. Based on this phylogeny, could you conclude that protist form a monophyletic group? a. yes b. no

yes