뒤로Anatomy & Physiology: Ch2
02:13
이 집합의 용어 (29)
Matter is anything that has mass and occupies space.
Solid, liquid, and gas.
An atom is the smallest unit of matter that retains its original properties and is made of subatomic particles.
Protons (positive), neutrons (neutral), and electrons (negative).
The number of protons in the nucleus defines the atomic number and the element.
An isotope is an atom with the same number of protons but a different number of neutrons, resulting in a different mass number.
A mixture is a physical combination of two or more elements or compounds without chemical bonding.
Suspension: large particles that settle out.
Colloid: small particles evenly distributed, do not settle.
Solution: very small particles dissolved in solvent, do not settle.
Molecule: two or more atoms chemically bonded.
Compound: molecule with atoms from different elements.
Atoms are most stable when they have eight electrons in their valence shell.
An ionic bond forms when electrons transfer from a metal to a nonmetal, creating oppositely charged ions that attract.
Cation: positively charged ion formed by losing electrons.
Anion: negatively charged ion formed by gaining electrons.
Covalent bonds form when two nonmetals share electrons; can be single, double, or triple bonds.
Electronegativity is an atom's ability to attract electrons; increases from bottom left to upper right on the periodic table.
Nonpolar covalent bonds: electrons shared equally.
Polar covalent bonds: electrons shared unequally, creating partial charges.
Weak attractions between the partially positive end of one dipole and the partially negative end of another dipole.
Acid: hydrogen ion donor.
Base: hydrogen ion acceptor.
The pH scale measures hydrogen ion concentration; 7 is neutral, below 7 acidic, above 7 basic.
A buffer resists changes in pH by neutralizing added acids or bases, maintaining homeostasis.
Dehydration synthesis: links monomers by removing water.
Hydrolysis: breaks polymers into monomers by adding water.
Simple sugars with 3-7 carbons; examples include glucose, fructose, galactose, ribose, and deoxyribose.
Three fatty acids linked to glycerol by dehydration synthesis; main storage form of fat.
They have a polar phosphate head and nonpolar fatty acid tails, important for cell membrane structure.
Primary: amino acid sequence.
Secondary: alpha helix or beta sheet folding.
Tertiary: 3D folding.
Quaternary: multiple polypeptide chains linked.
Loss of protein shape and function due to heat, pH changes, or chemicals disrupting bonds.
A nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and a phosphate group.
DNA has thymine (T); RNA has uracil (U) instead, which pairs with adenine.
ATP stores chemical energy in high-energy phosphate bonds and fuels cellular work.
A pairs with T (2 hydrogen bonds), and G pairs with C (3 hydrogen bonds), forming the double helix.