Biology Chapter 3: Cell Notes

Questions and Answers

According to cell theory, which of the following is true?

Cells are the largest unit of life

Cells can arise spontaneously from non-living matter

All living organisms are made of cells (correct)

Cells have no structural or functional role in organisms

Human cells are categorized into which two main types?

Stem cells and differentiated cells

Prokaryotic and eukaryotic cells

Plant and animal cells

Somatic and germ cells (correct)

Which of the following is NOT a function of the cell membrane?

Regulation of exchange with the environment

Sensitivity to the environment

Synthesis of proteins (correct)

Physical isolation of the cell interior

The hydrophobic tails in the phospholipid bilayer of the cell membrane primarily serve to:

<p>Prevent water from moving through the bilayer</p> Signup and view all the answers

Approximately what percentage of a cell's composition is water?

<p>60.1%</p> Signup and view all the answers

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.

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.