General Biology 1: Cell Theory and Structure

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Questions and Answers

What is the primary distinction between prokaryotic and eukaryotic cells?

Eukaryotic cells store their DNA in the nucleoid region, while prokaryotic cells do not.

Prokaryotic cells lack a membrane-bound nucleus, while eukaryotic cells have one. (correct)

Eukaryotic cells contain ribosomes, while prokaryotic cells do not.

Prokaryotic cells are generally larger than eukaryotic cells.

Which statement accurately reflects a tenet of the cell theory?

Cells can arise spontaneously from non-cellular matter.

Hereditary information is transferred to daughter cells during cell division. (correct)

Metabolism and energy flow occur outside of cells.

All cells are unique in their chemical composition.

What role do extracellular components or the extracellular matrix play in tissues?

They help determine the appearance and function of tissues. (correct)

They dictate the energy flow within a cell.

They are involved solely in cellular nutrient absorption.

They have no significant impact on tissue functionality.

Which part of the cell is responsible for storing genetic information in eukaryotic cells?

Nucleus Signup and view all the answers

What is NOT one of the main parts of a cell?

Ribosome Signup and view all the answers

How do all cells originate, according to cell theory?

Cells come from pre-existing cells by division. Signup and view all the answers

Which statement best describes the function of organelles in the cytoplasm?

Organelles perform distinct functions necessary for the cell's survival. Signup and view all the answers

What do all cells have in common, according to the modern tenets of cell theory?

They are made up of similar units of organization. Signup and view all the answers

What is the primary role of the rough endoplasmic reticulum (RER)?

Modification of proteins Signup and view all the answers

What distinguishes the smooth endoplasmic reticulum (SER) from the rough endoplasmic reticulum?

Lack of ribosomes Signup and view all the answers

What is the main function of the Golgi apparatus?

Sorting and packaging of lipids and proteins Signup and view all the answers

Which of the following best describes the function of lysosomes?

Digestive enzyme activity for recycling Signup and view all the answers

What unique function do plant vacuoles perform compared to lysosomes?

Storage of pigments and toxins Signup and view all the answers

What is the primary function of peroxisomes?

Oxidation reactions and detoxification Signup and view all the answers

How do plant vacuoles contribute to cellular function?

By balancing water levels Signup and view all the answers

Which organelle acts as the recycling facility in an animal cell?

Lysosome Signup and view all the answers

What is the primary function of the plasma membrane?

To protect the cell from its surroundings Signup and view all the answers

Which of the following statements correctly describes the composition of the plasma membrane?

It is composed of a phospholipid bilayer with embedded proteins Signup and view all the answers

Why must plasma membranes be flexible?

To enable cells like red blood cells to change shape as they pass through narrow capillaries Signup and view all the answers

Which organelle is NOT a membranous organelle?

Cytoskeleton Signup and view all the answers

What purpose does compartmentalization serve in eukaryotic cells?

It helps separate functions such as synthesis vs. breakdown Signup and view all the answers

Which structures are included in the endomembrane system?

Endoplasmic reticulum and Golgi apparatus Signup and view all the answers

What role do ribosomes play in the cell?

Synthesis of proteins Signup and view all the answers

What does the flexibility of the plasma membrane allow in cellular activities?

Shape changes during the passage through narrow capillaries Signup and view all the answers

Study Notes

Cell Theory

States that all organisms are composed of cells, the fundamental units of life, as articulated by Schleiden and Schwann in 1839.
Modern tenets include:
- All living things are composed of cells.
- Cells arise from pre-existing cells through division.
- Cells contain hereditary information passed during division.
- Cells share a similar chemical composition; all metabolic activity occurs within cells.

Prokaryotes vs Eukaryotes

Eukaryotic cells have a membrane-bound nucleus, while prokaryotic cells do not.
In prokaryotes, DNA is located in the nucleoid region without a nuclear membrane.

Cell Structure

Comprises three main parts: cell membrane, nucleus, and cytoplasm.
Cytoplasm contains organelles and a cytoskeletal framework.

Cell Membrane

A phospholipid bilayer with embedded proteins that separates the cell’s interior from its external environment.
Functions as a selective barrier, regulating the movement of substances in and out of the cell.
Must be flexible to accommodate shape changes in cells like red and white blood cells.

Organelles

Specialized structures within the cell that perform unique functions, categorized into membranous (e.g., mitochondria, Golgi apparatus) and non-membranous (e.g., ribosomes, cytoskeleton).
Compartmentalization within organelles allows conflicting processes to occur simultaneously without interference.

Endomembrane System

A collection of membranes and organelles in eukaryotic cells working together to modify, package, and transport lipids and proteins.
Key components include:
- Endoplasmic Reticulum (ER): Network of tubules; Rough ER has ribosomes for protein synthesis, while Smooth ER is involved in lipid synthesis.
- Golgi Apparatus: Membrane discs for sorting, tagging, packaging, and distributing proteins and lipids.
- Lysosomes: Contain digestive enzymes for recycling cell components and breaking down old structures.
- Vacuoles: Large organelles in plant cells that store water and waste; function in detoxification and may store pigments.
- Peroxisomes: Contain enzymes for oxidation reactions, producing hydrogen peroxide; involved in fatty acid and amino acid breakdown.

Additional Notes

The extracellular matrix impacts tissue appearance and function, providing structural and biochemical support to surrounding cells.
Understanding the endomembrane system's connection to organelles like lysosomes, peroxisomes, and the plasma membrane is crucial for comprehending cellular processes.

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Description

Explore the key concepts of cell theory, including the structure and function of the endomembrane system. This quiz covers the connections between the endomembrane system and other cell organelles such as lysosomes and peroxisomes. Test your knowledge and understanding of these fundamental biological concepts.