Cell Structure and Function

Introduction to Cells
Cells are the smallest structural and functional units of living organisms. All living things, from the simplest bacteria to complex humans, are made up of cells. The cell is often referred to as the building block of life

Definition of a Cell
A cell is the smallest structural and functional unit of life. Every living organism, from simple bacteria to humans, is made up of cells. The cell is often called the basic unit of life.


History of Cell Discovery

• Robert Hooke (1665): Observed cork tissue and introduced the term cell.
• Matthias Schleiden (1838): Stated that all plants are made of cells.
• Theodor Schwann (1839): Stated that all animals are made of cells.
• Rudolf Virchow (1855): Proposed that every cell comes from another existing cell (Omnis cellula e cellula).

The Cell Theory

• All living things are composed of cells.
• The cell is the basic unit of structure and function in living things.
• All cells come from pre-existing cells.

 

Types of Cells

• Prokaryotic cells: Simple cells without a nucleus, e.g., bacteria.
• Eukaryotic cells: More complex cells with a true nucleus, e.g., plant and animal cells.

Parts of the Cell

• Cell membrane: Protects the cell and controls the movement of substances.
• Cytoplasm: The fluid inside the cell where organelles are located.
• Nucleus: The control center of the cell that stores genetic material (DNA).
• Cell Organelles and Their Functions
• Nucleus – Control center of the cell.
• Mitochondria – The powerhouse of the cell, producing energy.
• Ribosomes – Sites of protein synthesis.
• Endoplasmic Reticulum – Transports materials within the cell.
• Golgi Apparatus – Packages and distributes proteins.
• Chloroplasts (in plants) – Perform photosynthesis.
• Vacuoles – Store food, water, and waste.
• Cell membrane – Regulates what enters and leaves the cell.
• Cell wall (in plants) – Provides support and protection.
• Differences Between Plant and Animal Cells
• Plant cells have a cell wall, chloroplasts for photosynthesis, and large vacuoles.
• Animal cells do not have a cell wall or chloroplasts, but have centrioles and usually smaller vacuoles.

 

 Pic taken from wordwall.net

 

Pic taken from wordwall.net

 

 TASK 1

Complete the following table of differences between animal cells and plant cells and put a check mark (√) in the animal or plant cell column if it has the organelle:

 

ORGANEL	ANIMAL CELL	PLANT CELL