Unit 1 Study Guide – The Chemistry and Organization of Life

Hierarchy of Biological Organization

The organization of life from atoms to ecosystems: atoms → molecules → organelles → cells → tissues → organs → organisms → populations → communities → ecosystems → biosphere.

DNA

The genetic material that carries information necessary for the growth, development, and reproduction of organisms.

Energy Flow vs. Matter Cycling

Energy flows in one direction through ecosystems, while matter is recycled.

Natural Selection

The process by which organisms adapt to their environment, driving evolution and diversity.

Inductive Reasoning

A method of scientific reasoning that involves forming general principles based on specific observations.

Deductive Reasoning

A method of scientific reasoning that involves making specific predictions based on general principles.

Hypothesis-based Science

An approach that involves formulating testable and falsifiable hypotheses.

Elements essential for life

96% of life’s matter consists of Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).

Protons, Neutrons, Electrons

Protons are positively charged, neutrons are neutral, and electrons are negatively charged particles within an atom.

Covalent Bonds

Strong chemical bonds formed when atoms share electrons.

Ionic Bonds

Chemical bonds formed through the transfer of electrons from one atom to another.

Hydrogen Bonds

Weak bonds important in biology, formed between molecules due to polar charges.

Chemical Reactions

Processes where matter is rearranged but neither created nor destroyed.

Cohesion

The tendency of water molecules to stick together.

Adhesion

The tendency of water molecules to stick to other surfaces.

High Specific Heat

The ability of water to stabilize temperature due to its high heat capacity.

Expansion Upon Freezing

Ice is less dense than liquid water, allowing it to float.

Versatile Solvent

Water's ability to dissolve many substances due to its polarity.

pH Scale

A measure of acidity or basicity; pH < 7 indicates acidity, pH = 7 is neutral, and pH > 7 indicates basicity.

Buffers

Substances that help maintain homeostasis by stabilizing pH levels.

Carbon's Versatility

Carbon can form four covalent bonds, allowing for a wide variety of complex molecules.

Isomers

Molecules that have the same chemical formula but different structures.

Functional Groups

Specific groups of atoms that determine the characteristics and reactivity of organic molecules.

Macromolecules

Large complex molecules including carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Organic molecules made of sugar units; includes monosaccharides, disaccharides, and polysaccharides.

Lipids

Hydrophobic biological molecules that include fats, phospholipids, and steroids.

Proteins

Biological macromolecules made of amino acids; their function depends on their structure.

Nucleic Acids

Macromolecules like DNA and RNA that store and transmit genetic information.

Fluid Mosaic Model

Describes the structure of cell membranes as a flexible layer of phospholipids with proteins embedded.

Passive Transport

Movement of substances across a cell membrane without the use of energy.

Active Transport

The movement of substances against their concentration gradient requiring energy (ATP).

Bulk Transport

Methods of transport that move large quantities of materials across cell membranes, including endocytosis and exocytosis.