Gen Biology II Ch24 LearnSmart

What is our current understanding of the phylogeny of organisms that possess chloroplasts?

All chloroplasts likely evolved from a single line of cyanobacteria, however, photosynthetic eukaryotes are not monophyletic.

Choose the 5 main supergroups of protists, according to our current understanding of protist phylogeny. Multiple select question.

Archaeplastida Opisthokonta SAR Excavata Amoebozoa

The grouping of protists into the kingdom Protista is

artificial, paraphyletic, or polyphyletic

Protist reproduction is ____.

asexual and sexual (depends on species)

Protists typically reproduce ____, although some have an obligate ____ reproductive phase.

asexually; sexual

Long, thin pseudopods supported by axial rods of microtubules are called

axopodia

The _____ of protists are long, thin protrusions supported by axial rods of microtubules.

axopodia

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

bacteria

A protist can undergo asexual reproduction by creating a small daughter cell which later grows to the adult size; this is known as

budding

In many protists, asexual reproduction produces a small daughter cell which later grows to the adult size; this is known as

budding

In the type of asexual reproduction called ____, cell division is preceded by several nuclear divisions, allowing the process of cytokinesis to produce several individuals almost simultaneously.

budding

The evolution of multicellularity allowed ____.

cells to become specialized

A ___ organism is made of cells that are permanently associated, but have little or no integration of cellular activities.

colonial

Even though chloroplasts of different algae are not monophyletic, it is thought that all chloroplasts derived from a single line of

cyanobacteria

A thick-walled unicellular life stage produced by many protists that can remain dormant during stressful periods is known as a(n)

cyst

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

endosymbiotic bacteria

Protists are alike in that all are

eukaryotic

The mechanisms of mitosis and cytokinesis most likely evolved ____.

in several steps

Cell division in schizogony ____.

is preceded by several nuclear divisions

Endosymbiotic bacteria are bacteria that can

live within other cells and perform specific functions for their host cells.

Amoebas are surrounded only by their plasma

membrane

An organism that is able to use both autotrophy and heterotrophy in order to obtain organic nutrients is a(n)

mixotroph

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

protists

Which of the following is an advantage of multicellularity?

It fostered the specialization of cells.

The earliest eukaryotic fossils we have discovered are found in rocks which are about ____.

1.5 billion years old

The first microfossils that show internal membranes and thicker walls are ____.

1.5 billion years old

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

A photosynthetic cyanobacterium

Which of the following are used by protists to locomote in their watery environments?

Cilia Flagella

What evidence supports the hypothesis that mitosis and cytokinesis did not evolve all at once?

Different, or possibly intermediate mechanisms of mitosis are observed in fungi and in some groups of protist compared to animals and plants.

Select all types of cell surfaces found in protists.

Extracellular matrix Glassy silica shell Plasma membrane

True or false: All chloroplasts likely evolved from a single line of cyanobacteria, therefore all organisms that have chloroplasts are monophyletic.

False.

Which of the following are structures that protists utilize to swim?

Flagella Cilia

Choose the three groups of protists that have true, if simple, multicellularity.

Green algae Red algae Brown algae

Which of the following is NOT matched correctly regarding the type of endosymbiosis that lead to the acquisition of chloroplasts in algae?

Green algae: Secondary endosymbiosis

Which of the following is the primary benefit of sexual reproduction in eukaryotes?

It allows for genetic recombination, thereby generating genetic variation.

Select all lines of evidence that support the endosymbiotic theory.

Mitochondria and chloroplasts divide by binary fission. Mitochondria and chloroplasts have smaller ribosomes than eukaryotes. Mitochondria and chloroplasts have their own circular DNA.

Which of the following statements about mitosis in protists is NOT true?

Mitosis in protists always occurs by the same mechanism as that found in animal cells.

Which of the following are nutritional strategies found in Protista?

Phagotrophs Mixotrophs Phototrophs

A mixotroph uses which of the following means to obtain nutrition?

Photoautotrophy and heterotrophy

Which of the following statements about the origin of chloroplasts in red, green and brown algae are true?

Red algae acquired their chloroplasts through primary endosymbiosis. Green algae acquired their chloroplasts through primary endosymbiosis. Brown algae acquired their chloroplasts through secondary endosymbiosis.

According to our current understanding, stramenopiles and alveolates are members of the supergroup

SAR

How are the members of Protists related and what is the implication of their relationship for their grouping in the kingdom Protista?

They are only distantly related; grouping is artificial

True or false: Asexual reproduction in protists involves mitosis, however, the process is often different than mitosis in multicellular animals.

True

In protists, a cyst is ____.

a life stage that can remain dormant during periods of unfavorable environmental conditions

The genome of a mitochondrion is typically composed of

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

Many different nutritional strategies are found in protists; they can be phagotrophs (ingest particles), _____ (ingest soluble nutrients), phototrophs, or ______ (both hetero- and phototrophs).

osmotrophs; mixotrophs

he RNA transcripts produced by mitochondria and chloroplasts are translated by smaller ______, which are very similar to those found in bacteria.

ribosome

In the type of asexual reproduction called ___ cell division is preceded by several nuclear divisions, allowing the process of cytokinesis to produce several individuals almost simultaneously.

schizogony

The process in which a eukaryotic host cell engulfs but does not consume another eukaryotic cell that possesses primary chloroplasts is ____________ endosymbiosis.

secondary

The process in which a eukaryotic host cell ingests and retains another type of eukaryotic cell is ____.

secondary endosymbiosis

___ reproduction allows for frequent genetic recombination which generates genetic variation - the starting point of evolution.

sexual