Lecture Notes: Understanding Cells

Introduction to Cells

• All living organisms are made of cells, including humans.
• Trillions of cells work together to sustain life in the human body.
• Cells are the fundamental unit of life that intrigue biologists like Boyce Rendsburger.

Composition and Functionality of Cells

• The human body is entirely composed of cells and cell-made substances, e.g., bones, skin, heart, muscles, and brain.
• Cells, despite their different functions and structures, operate fundamentally in the same way.

Characteristics of Cells

• Cells vary in size and shape, requiring a microscope for observation.
• Eukaryotic Cells:
  • Resemble microscopic factories powered by chemical reactions.
  • Nucleus: Functions as the cell's brain, controlling activities and housing DNA.
  • Cell Membrane: Protects the cell and regulates the movement of water, nutrients, and waste.
  • Transport Network: Composed of microtubules and intracellular membranes to move materials within the cell.

Cell Functions and Growth

• Cells break down raw materials for growth and to perform specific tasks.
• Embryonic development instructions direct cells to change and adopt new functions.
• Cells can sense and respond to wounds by signaling other cells for repair.

Coordination and Renewal of Cells

• Cells work together to maintain the body's balance.
  • Example: Heart muscle cells twitch independently but synchronize to maintain a heartbeat.
• Cells are constantly dying and being replaced via mitosis.
• Mitosis: The process where one cell divides into two new cells.
• Most body cells are younger than the organism due to continuous cell renewal.

Summary

Cells are essential components that not only sustain life but also work in harmony to perform complex bodily functions. They are constantly renewing, ensuring that the body remains functional and responsive to changes. Understanding cellular structures and processes is key to comprehending biological life.