ap bio unit 1 cheat sheet

2 min read 02-02-2025

Unit 1 of AP Biology sets the stage for the entire course, laying the groundwork for understanding the fundamental principles of life. This cheat sheet provides a concise yet comprehensive overview of key concepts, helping you master the material and ace your exams. Remember to consult your textbook and class notes for a complete understanding.

I. Chemistry of Life

This section focuses on the chemical building blocks of life and their interactions.

A. Water's Properties and Importance

Polarity: Water's polar nature (unequal sharing of electrons) leads to its unique properties.
Cohesion and Adhesion: Cohesion (water sticking to water) and adhesion (water sticking to other substances) are crucial for water transport in plants (capillary action).
High Specific Heat: Water resists temperature changes, creating a stable environment for organisms.
High Heat of Vaporization: A large amount of heat is needed to vaporize water, facilitating evaporative cooling.
Excellent Solvent: Water's polarity allows it to dissolve many ionic and polar substances.

B. Carbon's Importance in Biological Molecules

Carbon's versatility: Carbon's ability to form four covalent bonds allows for the creation of a vast array of organic molecules.
Functional groups: Hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), phosphate (-PO4), and methyl (-CH3) groups determine the properties of organic molecules.

C. Four Major Classes of Biological Macromolecules

Carbohydrates: Sugars and starches; function as energy sources and structural components (e.g., cellulose in plant cell walls, chitin in exoskeletons).
Lipids: Fats, oils, phospholipids, and steroids; function in energy storage, insulation, and membrane structure. Note the hydrophobic nature of lipids.
Proteins: Composed of amino acids; diverse functions including enzymes, structural support, transport, and signaling. Remember the four levels of protein structure: primary, secondary, tertiary, and quaternary.
Nucleic Acids: DNA and RNA; store and transmit genetic information. Understand the structure of nucleotides (sugar, phosphate, nitrogenous base).

II. Cell Structure and Function

This section explores the fundamental units of life: cells.

A. Prokaryotic vs. Eukaryotic Cells

Prokaryotes: Lack a nucleus and membrane-bound organelles; generally smaller and simpler than eukaryotes (e.g., bacteria).
Eukaryotes: Possess a nucleus and membrane-bound organelles; generally larger and more complex than prokaryotes (e.g., plants, animals, fungi, protists).

B. Organelles and Their Functions

Know the structure and function of key organelles, including:

Nucleus: Contains DNA.
Ribosomes: Sites of protein synthesis.
Endoplasmic Reticulum (ER): Rough ER (with ribosomes) synthesizes proteins; smooth ER synthesizes lipids and detoxifies.
Golgi Apparatus: Modifies, sorts, and packages proteins.
Lysosomes: Break down waste materials.
Mitochondria: Sites of cellular respiration (ATP production).
Chloroplasts (plants): Sites of photosynthesis.
Cell Membrane: Regulates what enters and exits the cell. Understand the fluid mosaic model.
Cell Wall (plants and some prokaryotes): Provides structural support.

C. Endosymbiotic Theory

This theory explains the origin of mitochondria and chloroplasts, proposing that they were once free-living prokaryotes that were engulfed by a host cell.

III. Cell Membrane Transport

This section focuses on how substances move across the cell membrane.

A. Passive Transport

Diffusion: Movement of substances from high to low concentration.
Osmosis: Diffusion of water across a selectively permeable membrane.
Facilitated Diffusion: Movement of substances across the membrane with the help of transport proteins.

B. Active Transport

Requires energy (ATP): Movement of substances against their concentration gradient (from low to high concentration).
Sodium-potassium pump: A key example of active transport.

C. Endocytosis and Exocytosis

Endocytosis: Uptake of substances into the cell by forming vesicles.
Exocytosis: Release of substances from the cell by fusing vesicles with the membrane.

This cheat sheet provides a foundational overview. Remember to delve deeper into each topic using your textbook, class notes, and practice questions. Good luck with your studies!