Question 1

_______ slime molds form multinucleate plasmodia and move by cytoplasmic streaming.

Accepted Answer

The answer of _______ slime molds form multinucleate plasmodia and...

Question 2

After a large volcanic eruption, a cloud dense with volcanic ash and pollution can stretch over a sizable portion of the Atlantic Ocean.Select the sentence that best describes the effect this event would be likely to have on phytoplankton and other oceanic wildlife.

Accepted Answer

A)  Phytoplankton populations would diminish because of limited light penetrance, resulting in population declines in species dependent on phytoplankton as a food source. 
B)  Phytoplankton populations would thrive with the additional nutrients provided by the volcanic ash, resulting in population increases in species dependent on phytoplankton as a food source. 
C)  Phytoplankton populations would remain unchanged as a result of this type of natural disaster. 
D)  The species distribution in phytoplankton populations would change, shifting toward species that are able to make sugars using photosynthesis. 
E)  There would be a dramatic decrease in atmospheric CO2 as phytoplankton converted the limited supply into sugars using photosynthesis.

Question 3

Microbial eukaryotes

Accepted Answer

A)  constitute a clade. 
B)  are all autotrophs. 
C)  are all incapable of photosynthesis. 
D)  are all heterotrophs. 
E)  are all unicellular.

Question 4

Refer to the figure, which shows endosymbiotic events in the evolution of chloroplasts.  Which statement concerning the events shown in part B of the figure is false?

Accepted Answer

A)  The engulfed cell possessed DNA prior to the endosymbiosis. 
B)  The engulfing cell possessed DNA prior to the endosymbiosis. 
C)  The engulfed cell was photosynthetic. 
D)  The engulfed cell was a prokaryote. 
E)  The events required a flexible cell membrane in the engulfing cell.

Question 5

Choose the statement that best describes a form of sex found in protists.

Accepted Answer

A)  Myxamoebas cycle through slug and spore stages to produce new myxamoebas. 
B)  Haploid foraminiferans lose their shells and fuse with one another to produce new individuals. 
C)  Two daughter diatoms of dissimilar sizes (one smaller than the original) are produced during reproduction. 
D)  Euglenids produce new individuals primarily through binary fission. 
E)  Two paramecia exchange micronuclei to produce individuals that are genetically distinct from the original organisms.

Question 6

In early eukaryotes, a flexible cell membrane did not play a role in

Accepted Answer

A)  an increase in surface area for gas and nutrient exchange. 
B)  the development of a nucleus. 
C)  endocytosis. 
D)  the development of ribosomes. 
E)  phagocytosis.

Question 7

The shells of foraminiferans are formed from the mineral _______.

Accepted Answer

The answer of The shells of foraminiferans are formed from...

Question 8

Refer to the figure.  The organisms shown most likely obtain nutrients by _______, and their movement most likely consists of _______.

Accepted Answer

A)  engulfing bacteria; free swimming using flagella 
B)  photosynthesis; free swimming with cilia 
C)  photosynthesis; floating in plankton 
D)  engulfing bacteria; floating in plankton 
E)  photosynthesis; free swimming using flagella

Question 9

Plasmodium, the organism that causes malaria, has a mass of organelles at the tip of the cell that enables it to enter cells in the human body.This characteristic suggests that Plasmodium is a member of the

Accepted Answer

A)  alveolates. 
B)  stramenopiles. 
C)  apicomplexans. 
D)  choanoflagellates. 
E)  rhizarians.

Question 10

If early eukaryotes had been unable to shed their rigid cell walls, then phagocytosis (the ability to engulf and digest other cells) would have been impossible, and eukaryotes would not possess mitochondria or _______.

Accepted Answer

The answer of If early eukaryotes had been unable to...

Question 11

Refer to the figure.  Why are thin, stiff pseudopods so useful to the radiolarian below?

Accepted Answer

A)  They increase the surface area of the radiolarian, allowing for phagocytosis of food particles. 
B)  They allow the radiolarian to float, giving its photosynthetic endosymbionts maximal access to light. 
C)  They are used to spear prey and immobilize them for saprobic absorption. 
D)  They play a role in locomotion, allowing the radiolarian to migrate toward nutrient-rich deposits. 
E)  They help defend the radiolarian from attacks by other protists.

Question 12

In the endosymbiosis theory of the origin of chloroplasts, secondary endosymbiosis did not involve or result in

Accepted Answer

A)  three membranes around an organelle. 
B)  endosymbiosis of a eukaryotic cell containing a chloroplast. 
C)  endosymbiosis of a prokaryotic cell containing a chloroplast. 
D)  a trace of the endosymbiont's nucleus in some instances. 
E)  generation of sugars through photosynthesis.

Question 13

Conjugation in Paramecium is called "sex without reproduction" because

Accepted Answer

A)  DNA is exchanged but no gametes are produced. 
B)  no DNA is exchanged, and no gametes are produced. 
C)  there is contact between the two individuals, but no new individuals are produced. 
D)  there is contact between the two individuals, but no gametes are produced. 
E)  DNA is exchanged, but no new individuals are produced.

Question 14

Refer to the figure.  Which statement about the eukaryotes shown is false?

Accepted Answer

A)  They produce a substance used as an emulsifier in ice cream. 
B)  They are almost exclusively marine organisms. 
C)  Some forms are found in the Sargasso Sea. 
D)  They are members of Plantae. 
E)  They are photosynthetic.

Question 15

The gametocytes of the malaria-causing organism Plasmodium

Accepted Answer

A)  develop into merozoites. 
B)  inhabit the salivary glands of Anopheles mosquitoes. 
C)  are the infective stage obtained from the insect vector. 
D)  are picked up by a feeding mosquito from the human host's blood. 
E)  give rise to zygotes within the mammalian circulatory system.

Question 16

In _______ alternation of generations, the two generations differ morphologically.

Accepted Answer

The answer of In _______ alternation of generations, the two...

Question 17

The evolutionary relationships among the five major groups of protists have been clarified best through

Accepted Answer

A)  the analysis of slowly evolving gene sequences. 
B)  the study of their life histories. 
C)  fossil evidence of the common ancestor of various microbial eukaryotes. 
D)  the analysis of different groups of protists in terms of morphologically conserved features. 
E)  the study of reproductive features present in different groups of protists.

Question 18

Which statement regarding conjugation in Paramecium is false?

Accepted Answer

A)  During asexual reproduction, all of the nuclei are copied before the cell divides. 
B)  Each cell ends up with two haploid nuclei, which then fuse. 
C)  During conjugation, two individuals line up against each other and fuse in the oral groove region of the body. 
D)  During conjugation, the macronucleus divides to produce two haploid nuclei, which are exchanged between paramecia. 
E)  The individuals that emerge from conjugation are both genetically distinct from the original individuals.

Question 19

Which feature is not a characteristic of the plasmodium of a plasmodial slime mold?

Accepted Answer

A)  Many nuclei enclosed in a single plasma membrane (coenocyte) 
B)  Multiple cells forming a pseudoplasmodium 
C)  Cytoplasmic streaming 
D)  Mitosis without cytokinesis 
E)  Formation of spore-bearing fruiting structures when conditions are unfavorable

Question 20

Both mitochondria and chloroplasts contain their own ribosomes.A photosynthetic eukaryotic cell possesses three different types of rRNA that are similar to rRNAs from three distantly related ancestors.Which process would be consistent with this condition?

Accepted Answer

A)  Secondary endosymbiosis of a chloroplast 
B)  Primary endosymbiosis of a mitochondrion and a chloroplast 
C)  Primary endosymbiosis of a chloroplast 
D)  Secondary endosymbiosis of a nucleus 
E)  Primary endosymbiosis of a mitochondrion

Exam 26: The Origin and Diversification of Eukaryotes