Chapter 28 - Protists

The earliest fossils that are likely eukaryotes were found in rocks that are approximately how old?

1.5 billion years old

The first microfossils that differed substantially in appearance from earlier prokaryotic cells are how old?

1.5 billion years old

Secondary

A eukaryote that possesses a chloroplast is engulfed and retained by another eukaryote host cell.

Tertiary

A eukaryote with a secondary chloroplast is engulfed and retained by another eukaryote host cell.

Primary

A prokaryote is engulfed and retained by a heterotrophic host cell.

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

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.

How do mitochondria and chloroplasts replicate?

Binary fission

Bacteria that live within other cells and perform specific functions for their host cells are called which of the following?

Endosymbiotic bacteria

How did mitochondria originate, according to the endosymbiotic theory?

Energy-producing bacteria were engulfed by larger bacteria and eventually evolved into mitochondria.

The nucleus and the ER of eukaryotes are thought to have evolved how?

From infoldings of the plasma membrane

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

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

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

You have an antibiotic that inhibits protein synthesis in many bacteria. What might the effect of this antibiotic be on mitochondria?

It is very likely that it will also inhibit protein synthesis in mitochondria.

What characteristics do eukaryotes have that prokaryotes lack?

Organelles A cytoskeleton A nuclear envelope

Which of the following were the first eukaryotes?

Protists

The process in which a eukaryotic host cell ingests and retains another type of eukaryotic cell that possesses plastids derived from cyanobacteria is called which of the following?

Secondary endosymbiosis

Which of the following likely led to the evolution of eukaryotes from early prokaryotic organisms?

The loss of a rigid cell wall, allowing membranes to fold inward An increase in membrane flexibility, allowing for one cell to engulf another

Which of the following describes the ribosomes in mitochondria?

They are similar to bacterial ribosomes.

Many antibiotics that inhibit protein synthesis in _______ also inhibit protein synthesis in ____ and chloroplasts.

bacteria mitochondria

According to the endosymbiotic theory, non-photosynthetic, energy-producing aerobic bacteria were engulfed by larger anaerobic bacteria and evolved into the organelles called

mitochondria

The significance of endosymbiosis in protist evolution centers on the origin of complex

organelles

Mitochondria can synthesize proteins with their own ____ which are very similar to those of bacteria in size and structure.

ribosomes