Chapter 28

How is an eukaryote classified as a protist?

A eukaryote is classified as a protist when it cannot be classified in any other eukaryotic group.

Which of the following is the best definition of endosymbiotic bacteria?

Bacteria that live within other cells and perform specific functions for their host cells

What group of protists primarily dwell in the soil, use either flagella or pseudopods for movement, and sometimes have shells made of silica?

Cercozoans

Because of its simple developmental system, this cellular slime mold is used as a model organism in studies of cell differentiation.

Dictyostelium discoideum

In fungi and some protists, the nuclear membrane does not dissolve during mitosis. In those organisms which of the following occurs?

Mitosis occurs within the nucleus, and after it is completed, the nucleus divides into two daughter nuclei, followed by division of the cell.

Cercozoa, Foraminifera, and Radiolaria are the three groups that comprise the __________.

Rhizaria

The evolution of multicellularity was advantageous because it allowed _____________.

cells to become specialized

The earliest eukaryotic cells likely evolved through the transfer of genes across species boundaries, a process called _______________ gene transfer.

horizontal

Euglenozoans exhibit extreme flexibility; they change shape while swimming thanks to strips of ______________ encircling their cells rather than a cell wall.

protein

Many amoebas move with "false feet," known as ________.

pseudopods

All oomycetes are either parasitic or ___________.

saprophytic

Radiolarians secrete glassy exoskeletons made of silica. Those exoskeletons Blank______.

give them distinct symmetrical shapes

Some protists, such as amoebas, are surrounded only by their plasma membrane, whereas others, such as diatoms and foraminifera, are surrounded by ______.

glassy shells of silica

Some slime molds produce a non-walled, multinucleate mass of cytoplasm called a(n) ___________.

plasmodium

The archaeplastid group that shares a common ancestor with the land plants is ____________.

charophyta

Autotrophic protists include those that are Blank______.

chemoautotrophic photosynthetic

Scientists hypothesize that photosynthetic bacteria were engulfed by other, larger cells and eventually evolved to become the organelles we now call _____________.

chloroplasts

Evidence suggests that members of the Opisthokonta, called __________ , are similar to the most likely common ancestor of all animals.

choanoflagellates

Chlamydomonas cells are small, green, and rounded, and have two__________ at their anterior end.

flagella

A distinguishing characteristic of red algae is that they lack ____________ and ____________.

flagella centrioles

Which of the following is an advantage of multicellularity?

It fostered the specialization of cells.

What is the function of the undulating membranes in parabasalids?

They are used for locomotion.

Kinetoplastids are a group of Euglenozoa that characteristically have Blank______.

a single mitochondrion

Among euglenozoa, the kinetoplastids are a second major group that are unique because they have ______.

a single mitochondrion in each cell

The nucleus and the ER of eukaryotes are thought to have evolved Blank______.

from infoldings of the plasma membrane

Select features of protists in the supergroup Excavata. -They move using flagella. -They are all photosynthetic. -Many possess a feeding groove. -Some have lost their nucleus.

-They move using flagella. -Many possess a feeding groove.

Select all features of dinoflagellates. -Multicellular -Two flagella -Prokaryotic -Photosynthetic

-Two flagella -Photosynthetic

Protists can exhibit both __________ and __________ reproduction.

Sexual Asexual

The ____________ life cycle of the brown algae is marked by alternation of generations between multicellular sporophyte and gametophyte generations.

haplodiplontic

Members of the phylum Foraminifera are ___________.

heterotrophic marine organisms

Amoebas are surrounded only by their plasma _______________.

membrane

During conjugation in ciliates, each of the two partners receives a pair of haploid___________ from the other partner.

micronuclei

In fungi and some protists, the _________ _____________ does not dissolve during mitosis.

nuclear membrane

Diplomonads are unique because they possess two________ per cell.

nuclei

Eukaryotic organisms that cannot be classified in the plant, animal, or fungal kingdoms are __________.

protists

Eukaryotic organisms that cannot be classified in the plant, animal, or fungal kingdoms are ___________.

protists

Although there are some parasitic species, most amoeba are free-living and are found in ___________ or ______________ environments.

soil freshwater

Apicomplexans are ___________ -forming parasites of ___________.

spore animals

Excavata, SAR, Archaeplastida, Amoebozoa, and Ophisthokonta are the names of the five protist ___________.

supergroups

Diatoms are photosynthetic,______________ organisms with unique double shells made of silica.

unicellular

Which of the following are currently recognized supergroups of protists? -Apicomplexa -Archaeplastida -Amoebozoa -Stramenopila -SAR -Ophisthokonta -Excavata

-Archaeplastida -Amoebozoa -SAR -Ophisthokonta -Excavata

Select all structures used by protists for locomotion. -Cilia -Flagella -Vacuoles -Pseudopods -ECM

-Cilia -Flagella -Pseudopods

Choose all of the following structures/mechanisms that can be used by cercozoans for motility. -Gliding -Cilia -Flagella -Pseudopods

-Flagella -Pseudopods

Select all evolutionary mechanisms that were important in the early evolution of eukaryotes. -Horizontal gene transfer -Evolutionary bottlenecks -Engulfing other cells -Artificial selection

-Horizontal gene transfer -Engulfing other cells

Select all features of the feeding phase of a plasmodial slime mold. -It does not have cell walls. -It has chitin cell walls, similar to fungi. -It is autotrophic. -It has multiple nuclei.

-It does not have cell walls. -It has multiple nuclei.

Which of the following are nutritional strategies found in protists? -Lysotrophs -Carbotrophs -Mixotrophs -Phototrophs -Phagotrophs

-Mixtrophs -Phototrophs -Phagotrophs

Select all nutritional strategies of oomycetes. -Autotrophic -Predatory -Parasitic -Saprophytic

-Parasitic -Saprophytic

Select all of the subgroups within the eukaryotic supergroup called SAR. -Amoebas -Opisthokonta -Rhizaria -Alveolates -Stramenopiles

-Stramenopiles -Alveolates -Rhizaria

Choose all features of Chlamydomonas. -They are unicellular microscopic organisms. -They are members of the green algae. -They contain unusual pigments in a phycobilisome. -They have two flagella at their anterior end. -They don't have centrioles.

-They are unicellular microscopic organisms. -They are members of the green algae. -They have two flagella at their anterior end.

Select all features of diplomonads. They are unicellular. They lack functional mitochondria. They are triploid. They propel themselves with cilia. They have two nuclei.

-They are unicellular. -They lack functional mitochondria. -They have two nuclei.

Which of the following are characteristics of red algae? -They are mostly flagellate organisms. -They have a haplodiplontic life cycle with both haploid and diploid phases. -They have two prominent centrioles in the center of the cell. -They have unique accessory pigments, e.g., phycoerythrin that allow them to live at greater depths.

-They have a haplodiplontic life cycle with both haploid and diploid phases. -They have unique accessory pigments, e.g., phycoerythrin that allow them to live at greater depths.

Which of the following statements about dinoflagellates are true? -They all have a single, long flagellum. -They have alveoli. -They possess kinetoplasts. -They are protected by plates composed of a cellulose-like material. -Their chloroplasts are similar to those of diatoms or brown algae.

-They have alveoli. -They are protected by plates composed of a cellulose-like material. -Their chloroplasts are similar to those of diatoms or brown algae.

Amoebas use their pseudopods to ______. -move -engulf food -photosynthesize -reproduce

-move -engulf food

What type of prokaryote might have formed endosymbiotic relationships with other larger bacteria, eventually evolving into a chloroplast?

A photosynthetic bacterium

The genome of a mitochondrion is typically composed of which of the following?

A single, circular, closed molecule of DNA, similar to that in bacteria

Which of the following is a branch of the supergroup SAR that is distinguished from other protists by the presence of flattened vesicles stacked in a continuous layer beneath their plasma membrane?

Alveolates

Mitochondria and chloroplasts contain their own DNA which is very similar in size and character to the DNA of __________ .

Bacteria or Prokaryotes

Which of the following protist groups is most closely related to the land plants?

Charophyta

The common ancestor to all animals was most likely similar to which of the following organisms?

Choanoflagellates

Infoldings of the prokaryotic plasma membrane are thought to have given rise to the eukaryotic endomembrane system that includes which of the following?

Endoplasmic reticulum (ER), and nuclear envelope

What group of protists is characterized by their lack of a cell wall, having instead flexible protein strips that give them flexibility and allow them to change shape while swimming?

Euglenozoans

Based on the latest data, the protists are divided into how many supergroups?

Five

The undulating membrane of parabasalids is used in which of the following?

Locomotion

Which of the following statements about amoeba is correct?

Most amoeba are free-living and can be found in the soil as well as freshwater.

Which of the following describes the flagella of protists in the Excavata?

Parabasalids and diplomonads have multiple flagella while euglenozoans have unique flagella.

Which of the following were the first eukaryotes?

Protists

Which of the following best describes reproduction among protists?

Protists typically reproduce asexually, but some undergo sexual reproduction regularly and others reproduce sexually only at times of stress.

Which of the following statement accurately describes when protists evolved relative to other eukaryotes?

Protists were the first eukaryotes to evolve.

The flowing projections of cytoplasm that are used by many protists for locomotion are called which of the following?

Pseudopods

The Alveolata, Rhizaria, and Stramenopila make up the eukaryotic supergroup called ______.

SAR

Radiolarians secrete glassy exoskeletons made of which of the following?

Silica

In most eukaryotes (with the exception of fungi and some protist groups), the separation of chromosomes during mitosis occurs in what part of the cell?

The cytoplasm

Which of the following are characteristic of Foraminifera? -They are heterotrophic. -Because they don't make shells, they cannot be studied using fossil records. -They resemble tiny snails. -They are marine. -They are the only group of protists, in which all members are macroscopic (can be seen with the unaided eye).

They are heterotrophic. They resemble tiny snails. They are marine.

In the SAR clade that includes the dinoflagellates, apicomplexans, and ciliates, a common trait is the presence of flattened vesicles below the plasma membrane called Blank______.

alveoli

In ciliates, sexual reproduction involves the process of_______________, during which two individual cells are attached for up to several hours.

conjugation

Photosynthetic stramenopile protists in the phylum Chrysophyta with double silicate shells are commonly called ______________.

diatoms

Cellular slime molds are important model organisms used in the study of cell_______________.

differentiation

Protists that possess two flagella, plates made of a cellulose-like material, and may be bioluminescent or produce toxins are__________.

dinoflagellates

Bacteria that live within other cells and perform specific functions for their host cells are called Blank______.

endosymbiotic bacteria