Introduction to Biology

Introduction to Biology

• Biology is the science that studies living organisms and their interactions with each other and their environment.
• It aims to understand the universe and the nature of life.
• All living organisms share key properties: order, response to stimuli, reproduction, growth and development, regulation, homeostasis, energy processing, and adaptation.
• Biology is a broad field with many different branches.

Chemical Foundation of Life

• Elements combine to form matter, including living things.
• Abundant elements in living organisms: carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus.
• These elements form proteins, carbohydrates, lipids, and nucleic acids.
• Four main elements found in all living organisms: oxygen, carbon, nitrogen, and hydrogen.
• The percentages of each element vary in humans, the atmosphere, and Earth's crust.

Key Properties of Living Organisms

• Order: Living organisms exhibit highly organized structures, ranging from single cells to complex systems.
• Response to Stimuli: Organisms react to various stimuli like light, touch, or chemicals. This may include movement toward or away from a stimulus.
• Reproduction: Single-celled organisms reproduce by duplicating their DNA and dividing. Multicellular organisms create new individuals through sex cells.
• Growth and Development: Organisms grow and develop following instructions encoded in their DNA.
• Regulation: Organism's functions are coordinated to maintain internal balance.
• Homeostasis: Abilities to maintain internal conditions (temperature, pH, ion concentration) despite environmental changes.
• Energy Processing: All organisms use energy for metabolism; plants convert sunlight, animals use chemical energy.
• Adaptation: Organisms adapt to their environments over time through genetic changes.

Levels of Organization

• Atoms
• Molecules
• Cells
• Tissues
• Organs
• Systems
• Organisms
• Populations
• Communities
• Ecosystems
• Biosphere

Biological Macromolecules

• Organisms get nutrients from food to survive.
• Large molecules are polymers (chains) made of smaller building blocks called monomers.
• Four major classes of macromolecules: Carbohydrates, lipids, proteins, and nucleic acids.
• These macromolecules are organic (contain carbon), along with hydrogen, oxygen, and nitrogen.

Types and Functions of Proteins

• Proteins have diverse functions in organisms. The chart lists several examples. (Note this is a summary, the provided examples would show detailed examples of each)