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Atomic Structure and Properties

• Atomic Number

  • Represents the number of protons in an atom.

  • Determines the identity of the element.

• Atomic Weight

  • Determined by the total number of protons and neutrons in the nucleus.

• Valence Shell

  • Refers to the outermost electron shell of an atom.

  • Involved in chemical bonding.

• Inert Gases

  • Gases such as neon and argon that do not readily react with other elements due to a full valence shell.

• Ion

  • An atom that has gained or lost electrons, resulting in a net charge.

• Isomers

  • Molecules with the same chemical formula but different structures, affecting their properties.

• Isotopes

  • Variants of an element with the same number of protons but different numbers of neutrons.

Solutions and Concentration

• Solvent in a Solution

  • The substance doing the dissolving; not always water.

• Tonicity

  • Refers to a solution’s ability to influence water movement in/out of cells.

    • Isotonic: Equal concentration.

    • Hypertonic: Higher solute concentration, causing cells to shrink.

    • Hypotonic: Lower solute concentration, causing cells to swell.

• Hypothesis

  • A testable explanation for observations not yet proven.

Cell Structure

• Biology

  • The scientific study of living organisms, including structure, function, growth, and evolution.

• Eukaryotic Cells

  • Have a nucleus and membrane-bound organelles.

• Prokaryotic Cells

  • Lack a defined nucleus and membrane-bound organelles.

• Nucleus of a Cell

  • Contains the cell’s genetic material (DNA).

Cellular Organelles

• Mitochondrion

  • Known as the powerhouse of the cell; site of cellular respiration.

• Plasma Membrane

  • A selectively permeable barrier surrounding the cell.

• Cell Wall

  • Found in plant and bacterial cells; provides structural support.

• Golgi Apparatus

  • Modifies, sorts, and packages proteins for secretion.

• Ribosomes

  • Responsible for protein synthesis in cells.

• Rough Endoplasmic Reticulum (ER)

  • Studded with ribosomes; involved in protein production.

• Lysosome

  • Breaks down waste materials and cellular debris.

• Chloroplasts

  • Found in plant cells; responsible for photosynthesis.

Biochemical Reactions

• Enzymes

  • Biological catalysts that facilitate chemical reactions in cells.

• Substrate Binding

  • The substrate binds to the enzyme's active site to undergo a reaction.

• ATP (Adenosine Triphosphate)

  • Primary energy carrier in cells.

Transport Mechanisms

• Osmosis

  • The movement of water across a semipermeable membrane.

• Diffusion

  • Movement of molecules from an area of high concentration to low concentration.

• Facilitated Diffusion

  • Requires a transport protein to help move substances across membranes without energy.

• Active Transport

  • Movement of molecules against their concentration gradient; requires ATP.

• Concentration Gradient

  • Difference in the concentration of a substance across a space.

Chemical Reactions

• Dehydration Synthesis

  • Links monomers by removing water molecules.

• Hydrolysis

  • Breaks down polymers using water.

• Monomer

  • A single building block of a polymer.

Chemical Bonds

• Organic Molecule Elements

  • Main elements include carbon, hydrogen, and oxygen.

• Types of Bonds

  • Covalent Bonds: Formed by sharing electrons.

  • Ionic Bonds: Formed by the transfer of electrons.

  • Hydrogen Bonds: Weak interactions between water molecules.