Module 12

Question 1

What defines eukaryotic cells?

Answer 1

The presence of a nucleus

Eukaryotic cells also feature a dynamic cytoskeleton and membrane system.

Question 2

What role does the network of proteins inside eukaryotic cells serve?

Answer 2

Allows them to change shape, move, and transfer substances into and out of the cell.

Question 3

What do dynamic membranes in eukaryotic cells provide?

Answer 3

New possibilities for movement and feeding.

Question 4

Where do eukaryotic cells compartmentalize their machinery for energy metabolism?

Answer 4

Into mitochondria and chloroplasts.

Question 5

What hypothesis proposes that chloroplasts and mitochondria originated from free-living bacteria?

Answer 5

The endosymbiotic hypothesis

This hypothesis suggests that these organelles were once independent bacteria that became symbiotic with eukaryotic cells.

Question 6

What types of bacteria are chloroplasts and mitochondria genetically similar to?

Answer 6

Chloroplasts are similar to cyanobacteria; mitochondria are similar to proteobacteria

These similarities support the endosymbiotic hypothesis.

Question 7

Do chloroplasts and mitochondria have their own genomes?

Answer 7

Yes

This is one of the key pieces of evidence for the endosymbiotic hypothesis.

Question 8

What are common relationships in nature that involve different species living together?

Answer 8

Symbioses

Symbiotic relationships can be mutualistic, commensal, or parasitic.

Question 9

Which domain of life are eukaryotes more closely related to, Archaea or Bacteria?

Answer 9

Archaea

This finding has significant implications for understanding evolutionary relationships.

Question 10

What is the proposed ancestor of modern eukaryotic cells?

Answer 10

Either a primitive eukaryote descended from archaeal ancestors or an archaeon that engulfed a bacterium

This emphasizes the complexity of eukaryotic evolution.