Biology 101: An Introduction, Slides of Biology

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Introduction to Biology

BIO 101

What is Biology?

Biology is the scientific study of life and living organisms Includes structure, function, growth, origin, evolution, and distribution of life Biology connects chemistry, physics, and environmental science Helps explain how living systems work at different scales

Atoms form molecules (e.g., water, glucose) Molecules build organelles inside cells Cells are the basic units of life Similar cells form tissues (muscle, nerve) Tissues combine to form organs (heart, lungs) Organ systems work together in an organism Groups of organisms form populations and ecosystems

Levels of Biological

Organization

The Cell Theory

All living organisms are composed of cells The cell is the smallest unit capable of life All cells come from preexisting cells Cell theory is a unifying concept in biology Modern biology focuses heavily on cellular processes

Cell Structure and Function

Cell membrane: regulates movement of substances Cytoplasm: site of many chemical reactions Nucleus: stores DNA and controls cell activity Mitochondria: produce ATP (energy) Ribosomes: build proteins Endoplasmic reticulum and Golgi apparatus: modify and transport proteins

Macromolecules

Carbohydrates Provide short-term energy Examples: glucose, starch Lipids Long-term energy storage Form cell membranes Proteins Enzymes, structure, signaling Made of amino acids Nucleic Acids DNA and RNA store genetic information

All cellular work requires energy ATP (adenosine triphosphate) is the energy currency of cells Energy is released when ATP is broken down Photosynthesis captures energy from sunlight Cellular respiration converts food into usable energy

Energy and ATP

DNA is a double-stranded molecule Contains instructions for building proteins Genes are segments of DNA DNA is passed from parent to offspring Mutations are changes in DNA sequence

DNA and Genes

Cells divide for growth, repair, and reproduction Mitosis Produces identical body cells Used for growth and healing Meiosis Produces gametes (sperm and eggs) Creates genetic variation

Cell Division

Evolution and Natural

Selection

Evolution explains unity and diversity of life Natural selection favors traits that increase survival Individuals do not evolve—populations do Evidence includes fossils, DNA, and comparative anatomy Evolution is central to all biology

What to Expect in BIO-101:

Focus on concepts rather than memorization Use of scientific vocabulary and diagrams Laboratory experiments and data analysis Application of biology to real-world problems Preparation for advanced biology and health sciences