BSC Week 10 Flashcards

Questions and Answers

What is a eukaryotic cell?

A type of cell that has a membrane-enclosed nucleus and other membrane-enclosed organelles.

What is the endomembrane system?

A series of internal membranes and membrane-enclosed organelles that are largely interconnected.

What is endosymbiosis?

A symbiotic relationship in which one species resides within another species.

What is a protist?

Any eukaryote that is not a plant, animal, or fungus. Signup and view all the answers

What is a protozoan?

A protist that lives primarily by ingesting food; a heterotrophic, animal-like protist. Signup and view all the answers

Where are protozoans commonly found?

Almost all aquatic and moist habitats. Signup and view all the answers

What is an amoeba?

A general term for a protozoan characterized by great structural flexibility and the presence of pseudopodia. Signup and view all the answers

What are slime molds?

A type of protist that has amoeboid cells. Signup and view all the answers

What are algae?

Photosynthetic protists able to produce their own food from sunlight. Signup and view all the answers

What are seaweeds?

Large, multicellular marine algae that grow on rocky shores and in shallow marine habitats. Signup and view all the answers

What is a colony in biology?

A collection of members of the same species, usually prokaryotes or protists, living in close contact. Signup and view all the answers

What describes the cells of colonies?

Identical and can live independently. Signup and view all the answers

What describes the cells of multicellular organisms?

Specialized and incapable of living independently. Signup and view all the answers

Which of the following organisms are classified within the protists under algae? (Select all that apply)

Seaweeds Signup and view all the answers

How long did it take in the history of life on Earth to go from the first prokaryotic cells to the first eukaryotic cells?

Over a billion years. Signup and view all the answers

How did mitochondria and chloroplasts arise in eukaryotic cells?

Via endosymbiosis, where mitochondria and chloroplasts were independent prokaryotic organisms that were engulfed by a larger cell. Signup and view all the answers

Why is it hard to classify protists?

Because they differ in their complexity, some being unicellular, some being multicellular, they differ in their nutrition and energy use, and they come in such a wide variety of size and shape. Signup and view all the answers

What are the steps toward multicellularity, in the correct order?

First a colony of protists forms, then some protists start to specialize in specific tasks, and finally some cells become gametes. Signup and view all the answers

An organism is considered truly multicellular when ________.

its cells cannot survive on their own. Signup and view all the answers

Approximately when did the earth's crust solidify?

4 billion years ago. Signup and view all the answers

Which began first, multicellular life in the ocean or land plants?

Multicellular life in the ocean. Signup and view all the answers

When did the first eukaryotic cells form?

2.1 billion years ago. Signup and view all the answers

Which was first on the planet, prokaryotes or eukaryotes?

True Signup and view all the answers

Based on the endosymbiosis theory, how would you expect chloroplasts to divide when a plant cell divides?

Via binary fission. Signup and view all the answers

By what means do amoebas and slime molds move?

Pseudopodia. Signup and view all the answers

Study Notes

Eukaryotic cells feature a membrane-enclosed nucleus and organelles.
The endomembrane system comprises interconnected internal membranes and organelles in eukaryotic cells.
Endosymbiosis describes a symbiotic relationship where one organism lives within another.

Protists and Their Diversity

Protists are eukaryotic organisms that do not fall under the categories of plants, animals, or fungi.
Protozoans are heterotrophic protists that primarily ingest food, resembling animal behavior.
Protozoans thrive in aquatic and moist environments.

Types of Protists

Amoebas are flexible protozoans characterized by pseudopodia for movement and feeding.
Slime molds are a unique category of protists with amoeboid characteristics.
Algae are photosynthetic protists that convert sunlight into food, producing oxygen as a byproduct.
Seaweeds are large, multicellular algae that inhabit rocky shorelines and shallow marine waters.

Colonies vs. Multicellularity

Colonies consist of genetically identical prokaryotic or protist members living closely, with cells capable of independent survival.
Multicellular organisms are formed by specialized cells that cannot survive alone, contrasting with colony cells.

Evolutionary Milestones

Organisms within protists include algae such as seaweeds, diatoms, and dinoflagellates.
The transition from prokaryotic to eukaryotic cells spanned over a billion years.
Mitochondria and chloroplasts in eukaryotic cells originated from independent prokaryotic organisms through endosymbiosis.
Challenges in classifying protists arise from their varied complexity, nutritional methods, and diverse forms.

Steps to Multicellularity

The progression to multicellularity starts with protist colonies, followed by cell specialization, culminating in the formation of gametes.
True multicellularity occurs when the cells within an organism cannot survive independently.

Timeline of Life on Earth

The Earth's crust solidified approximately 4 billion years ago.
The first eukaryotic cells emerged around 2.1 billion years ago, following the earlier existence of prokaryotic cells.

Cell Division and Movement

Chloroplasts are expected to divide through binary fission, mirroring bacterial division methods.
Amoebas and slime molds utilize pseudopodia for locomotion.

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Description

Test your understanding of key biological concepts with these flashcards from Week 10 of your BSC course. Topics include eukaryotic cells, the endomembrane system, endosymbiosis, and protists. Perfect for quick revision and enhancing your grasp of cellular biology.