IndietroGeneral Biology Key Concepts
Termini in questo insieme (33)
Matter is anything that has mass and takes up space. An atom is the smallest unit of an element. An ion is an atom or molecule with a charge. A molecule is two or more atoms bonded together. A compound is a molecule made of different elements.
Protons (positive charge) and neutrons (neutral) are in the nucleus. Electrons (negative charge) orbit the nucleus.
The periodic table shows atomic number (protons), atomic mass, and electronegativity of elements.
Emergent properties are new traits that arise from the interaction of parts. Example: Water's ability to moderate temperature arises from hydrogen bonding.
Essential elements are required for life. The four main ones are carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).
Atomic number is the number of protons. Mass number is the sum of protons and neutrons in the nucleus.
Valence electrons are electrons in the outer shell; they determine an atom's chemical reactivity and bonding.
Ionic bonds transfer electrons, covalent bonds share electrons, and hydrogen bonds are weak attractions between polar molecules.
Electronegativity is an atom's ability to attract electrons in a bond.
Atoms react to fill their outer electron shells and achieve a stable electron configuration.
Water is polar because oxygen is more electronegative than hydrogen, creating partial charges.
Cohesion is water molecules sticking to each other, adhesion is water sticking to other surfaces, and surface tension is the resistance of water's surface to external force.
Water absorbs heat without large temperature changes due to its high specific heat, stabilizing environments.
Ice is less dense than liquid water because hydrogen bonds form a lattice that spaces molecules apart.
A solution is a homogeneous mixture, the solvent dissolves substances, and the solute is dissolved.
Hydrophobic molecules repel water (nonpolar), while hydrophilic molecules attract water (polar or charged).
Acids increase hydrogen ion concentration, bases decrease it. The pH scale measures acidity from 0 (acidic) to 14 (basic).
A buffer stabilizes pH by absorbing or releasing hydrogen ions to resist changes.
Hydrocarbons are molecules of only carbon and hydrogen; they store energy and form the backbone of organic molecules.
Monomers are small building blocks; polymers are chains of monomers linked by covalent bonds.
The four classes are carbohydrates, lipids, proteins, and nucleic acids.
Condensation links monomers by removing water; hydrolysis breaks polymers by adding water.
Monosaccharides are single sugars, disaccharides are two sugars linked, and polysaccharides are long chains of sugars.
Primary: amino acid sequence; secondary: alpha helices and beta sheets; tertiary: 3D folding; quaternary: multiple polypeptide chains.
Saturated fats have no double bonds, unsaturated fats have one or more double bonds, and trans fats have artificially hydrogenated double bonds.
An amphipathic molecule has both hydrophilic (polar) and hydrophobic (nonpolar) parts.
A nucleotide has a sugar, phosphate group, and nitrogenous base; variations occur in the base and sugar.
5’ and 3’ refer to the carbon numbers in the sugar; nucleotides link 5’ phosphate to 3’ hydroxyl forming the backbone.
Prokaryotes lack a nucleus and membrane-bound organelles; eukaryotes have both.
The endomembrane system includes the nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, and plasma membrane, coordinating protein and lipid transport.
The theory that mitochondria and chloroplasts originated from free-living prokaryotes engulfed by ancestral eukaryotic cells.
The cytoskeleton includes microtubules (shape, transport), microfilaments (movement, support), and intermediate filaments (structural stability).
The extracellular matrix provides structural support, mediates cell communication, and influences cell behavior.