Questions and Answers
According to cell theory, which of the following is true?
Human cells are categorized into which two main types?
Which of the following is NOT a function of the cell membrane?
The hydrophobic tails in the phospholipid bilayer of the cell membrane primarily serve to:
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Approximately what percentage of a cell's composition is water?
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Study Notes
Cell Theory
- Established by Robert Hooke in the 1600s, setting the foundation for cell biology.
- Cells are classified as somatic (body cells) or sex cells (reproductive cells).
- Size of cells typically ranges from 10 micrometers to several hundred micrometers.
- Cells are composed of approximately 60.1% water, highlighting their aqueous nature.
Fundamental Principles of Cell Theory
- All living organisms are composed of one or more cells.
- All cells arise from pre-existing cells, emphasizing cellular division as a key process.
- Cells serve as the basic structural and functional units in all living organisms.
Cell Membrane (Plasma Membrane)
- Functions of the cell membrane include:
- Physical isolation: Separates the internal environment of the cell from the external surroundings.
- Regulation of Exchange: Controls the transport of substances into and out of the cell.
- Sensitivity to Environment: Contains receptors that respond to various stimuli, enabling communication and interaction.
- Structural Support: Provides a framework that helps maintain the cell's shape and structural integrity.
Membrane Lipids
- The cell membrane is primarily composed of a phospholipid bilayer.
- Consists of two layers of lipids, with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward.
- The arrangement of the hydrophobic tails creates a barrier that limits water and certain substances from easily passing through the membrane, contributing to selective permeability.
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Description
Explore the fundamental concepts of cell theory and the structure of cells in this quiz based on Chapter 3 of your biology textbook. Learn about the functions of the cell membrane and the components that make up living organisms. Test your knowledge on key definitions and functions critical to understanding cellular biology.