Cell Structure and Function

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Questions and Answers

What role do membrane transport proteins primarily serve within the cell?

Regulating energy usage

Catalyzing reactions of entering molecules

Determining which molecules enter the cell (correct)

Building cell structure

How do catalytic proteins, or enzymes, influence the behavior of the cell?

By controlling the reactions of entering molecules (correct)

By shielding the cell from external threats

By enhancing membrane transport efficiency

By modifying the cell's DNA

What does the genetic information in a cell ultimately dictate?

The nutrients required for cell survival

The cell's exposure to environmental factors

The proteins that determine cell chemistry and behavior (correct)

Only the shape of the cell

What is the primary function of motor proteins within the cell?

Using ATP hydrolysis to perform various movements Signup and view all the answers

What phenomenon describes the random motion of molecules at the microscopic scale in cells?

Thermal or Brownian motion Signup and view all the answers

How are the components within a cell described in terms of organization?

They self-assemble and must be highly ordered Signup and view all the answers

Who first observed thermal motion while examining pollen grains in water?

Robert Brown Signup and view all the answers

What is the approximate size of the simplest cells as mentioned in the content?

1 micrometer Signup and view all the answers

What distinguishes archaea from bacteria at a cellular level?

Differences in cell wall chemistry Signup and view all the answers

Which of the following accurately describes most archaea?

Poorly understood and often identified via DNA sequencing Signup and view all the answers

What is a key application of engineering techniques in bacteria?

Producing human pharmaceuticals and biofuels Signup and view all the answers

In what aspect are archaea genomes more closely related?

To eukaryotes than to bacteria Signup and view all the answers

How do archaea and eukaryotes primarily differ from bacteria?

Type of lipids in their membranes Signup and view all the answers

Which statement about the size of archaea is true?

They are the same size as bacteria Signup and view all the answers

Which of the following is a characteristic of prokaryotes?

Presence of intracellular membranes Signup and view all the answers

What role do archaea play in the broader context of biodiversity?

They are among the least understood organisms on Earth Signup and view all the answers

What is the length of the bacterium Epulopiscium fishelsoni?

600 μm Signup and view all the answers

Which of the following species is known to cause cholera?

Vibrio cholerae Signup and view all the answers

What structure allows Vibrio cholerae to move?

Flagellum Signup and view all the answers

What critical role does bacteria like Escherichia coli play in human health?

Digesting food Signup and view all the answers

Which feature distinguishes the bacterium with a simple internal organization as shown in the drawing?

Ribosomes in cytosol Signup and view all the answers

How many people does cholera kill approximately each year worldwide?

100,000 Signup and view all the answers

Which of the following best describes the overall size of most bacteria?

A few micrometers Signup and view all the answers

Which bacterium is primarily studied in laboratory settings due to its importance in research and health?

Escherichia coli Signup and view all the answers

What is the primary role of the plasma membrane in a living cell?

It acts as a selective barrier for nutrient and waste exchange. Signup and view all the answers

Why do plants require simpler nutrients compared to animals?

They harness energy from sunlight to synthesize organic molecules. Signup and view all the answers

What characteristic defines amphiphilic molecules?

They contain both hydrophilic and hydrophobic parts. Signup and view all the answers

What happens if a cell does not have a plasma membrane?

It cannot maintain its integrity as a coordinated chemical system. Signup and view all the answers

What does the term 'hydrophilic' refer to in the context of cell membranes?

A water-soluble part of a molecule. Signup and view all the answers

Which of the following statements is true regarding animal and some bacteria in terms of nutrient acquisition?

They require ready-made organic molecules from other living sources. Signup and view all the answers

What is the function of the hydrophobic part of a phospholipid molecule?

It repels water and helps form a barrier. Signup and view all the answers

How do cells concentrate nutrients from their environment?

Using the selective nature of the plasma membrane. Signup and view all the answers

What type of relationship do tube worms have with sulfur-oxidizing bacteria?

Symbiotic Signup and view all the answers

Which type of energy do the sulfur-oxidizing bacteria harness for nourishment?

Chemical energy Signup and view all the answers

What adaptations have the tube worms undergone to thrive at hydrothermal vents?

Absence of a digestive system Signup and view all the answers

Which of the following invertebrate marine animals is mentioned as living off the microorganisms at the vents?

Giant marine worms Signup and view all the answers

How do ecosystems at hydrothermal vents compare to typical ecosystems on solid land?

They are sustained by geochemical energy. Signup and view all the answers

What is the primary source of nourishment for tube worms?

Symbiotic bacteria Signup and view all the answers

What characteristic is true of the ecosystem at hydrothermal vents?

It is independent of sunlight. Signup and view all the answers

How did tube worms likely evolve to become adapted to their unique environment?

They underwent secondary adaptation from more conventional animals. Signup and view all the answers

Study Notes

Cell Structure

All cells require nutrients and a plasma membrane to maintain integrity, and to transport molecules.
The plasma membrane is a selective barrier that allows the cell to concentrate nutrients and retain produced molecules, while excreting waste.
The molecules forming the plasma membrane are amphiphilic. This means they have a hydrophilic (water-soluble) part and a hydrophobic (water-insoluble) part.
The transport proteins in the membrane determine what molecules enter the cell.
Enzymes inside the cell catalyze reactions that the incoming molecules undergo.
All cells employ a similar biochemical factory system, but the details of their transactions differ.
Plants can make their own nutrients using energy from sunlight.
Animals and some bacteria require consuming living organisms to obtain their nutrients.
The DNA sequence determines the chemistry, form, and behavior of a cell.

Cellular Scale and Motion

Cells are microscopic and operate at a scale where thermal motion is important.
Thermal motion is also called Brownian motion
Motor proteins use the energy of ATP hydrolysis for a variety of purposes, including pumping ions, moving assemblies, and propelling cells.

Prokaryotes

Prokaryotes are small and lack internal, membrane-bound organelles.
Bacteria can be used as "factories" to produce pharmaceuticals and biofuels.

Archaea

The archaea domain is the least understood.
They are small and lack internal organelles, but differ from bacteria in their cell walls, membrane lipids, and metabolic processes.
Genetically, archaea are more closely related to eukaryotes than bacteria.

Hydrothermal Vents

Hydrothermal vents release energy from geochemical reactions.
Microorganisms thrive in these environments, using the energy from the vents.
Tube worms live in symbiosis with sulfur-oxidizing bacteria at hydrothermal vents. These bacteria supply nourishment to the worms.

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Description

Explore the fundamental components of cell structure, including the plasma membrane, transport proteins, and enzymes. Learn about the differences in nutrient acquisition between plant and animal cells, as well as the role of DNA in cellular behavior. This quiz covers key concepts essential for understanding cellular biology.