뒤로Anatomy & Physiology: Ch. 1-2
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Matter is anything that has mass and occupies space. It can be seen, smelled, or felt and exists in three states: solid, liquid, and gas.
Energy is the capacity to do work or put matter into motion. It exists as kinetic energy (energy in action) and potential energy (stored energy).
Carbon, oxygen, hydrogen, and nitrogen make up 96% of the human body mass.
Protons (+1 charge), neutrons (0 charge), and electrons (-1 charge) make up atoms. Protons and neutrons are in the nucleus; electrons orbit the nucleus.
The planetary model shows electrons in fixed circular orbits, while the orbital model depicts electrons as clouds in probable regions called orbitals.
Atomic number is the number of protons in the nucleus. Mass number is the total number of protons and neutrons.
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, resulting in different mass numbers.
A radioisotope is an unstable isotope that decomposes, releasing energy (radioactivity). They are used in medicine for diagnosis and treatment.
A molecule is two or more atoms bonded together. A compound is a molecule with two or more different kinds of atoms.
Solutions (homogeneous), colloids (heterogeneous with larger particles), and suspensions (heterogeneous with very large particles that settle out).
A solution is a homogeneous mixture with very small solute particles that do not settle out. Example: mineral water.
A colloid is a heterogeneous mixture with larger solute particles that scatter light but do not settle. Example: Jell-O.
A suspension is a heterogeneous mixture with very large particles that settle out. Example: blood.
Atoms tend to gain, lose, or share electrons to have eight electrons in their valence shell for stability, except hydrogen and helium which aim for two.
Ionic bonds form when valence electrons are transferred from one atom to another, creating oppositely charged ions that attract each other.
Covalent bonds form by sharing valence electrons. Types include nonpolar (equal sharing) and polar (unequal sharing) covalent bonds.
Hydrogen bonds are weak attractions between a hydrogen atom with a partial positive charge and an electronegative atom of another molecule.
Synthesis (building molecules), decomposition (breaking down molecules), and exchange (both making and breaking bonds).
Exergonic reactions release energy; endergonic reactions absorb energy. Exergonic reactions have products with less potential energy than reactants.
Temperature, concentration of reactants, particle size, and presence of catalysts (enzymes) affect reaction rates.
Water, salts, acids, and bases are major inorganic compounds essential for physiological functions.
High heat capacity, high heat of vaporization, polar solvent properties, reactivity, and cushioning.
Acids donate protons (H+), and bases accept protons. Bases release hydroxyl ions (OH-) in solution.
The pH scale measures hydrogen ion concentration, ranging from 0 (acidic) to 14 (basic), with 7 being neutral.
Dehydration synthesis joins monomers by removing water; hydrolysis breaks polymers by adding water.
Carbohydrates, lipids, proteins, and nucleic acids.
Monosaccharides are simple sugars and monomers of carbohydrates. Examples include glucose, fructose, ribose, and deoxyribose.
Triglycerides are fats/oils made of glycerol and three fatty acids. They store energy, provide insulation, and protect organs.
Primary (amino acid sequence), secondary (alpha helix or beta sheet), tertiary (3D folding), and quaternary (multiple polypeptides).
Enzymes are biological catalysts that lower activation energy and speed up reactions without being consumed.
Nucleic acids are polymers of nucleotides. The two major types are DNA (genetic blueprint) and RNA (protein synthesis).
ATP (adenosine triphosphate) stores and provides immediate energy for cellular work by transferring phosphate groups.