Unit 3: Macromolecules and Chemical Reactions

Vocabulary practice flashcards covering Unit 3: Macromolecules, Water Properties, Chemical Reactions, and Enzyme Function based on class notes.

Water ($H_2O$)

An odorless, colorless, tasteless molecule composed of 2 hydrogen atoms and 1 oxygen atom; it is the most abundant molecule in living organisms and exists in solid, liquid, and gas states.

Polar Molecule

A molecule with an unequal sharing of electrons that results in a slightly negative charge on one end and a slightly positive charge on the other, such as water's bent shape.

Water Polarity and Bonding Diagram

Diagram illustrating covalent bonds between oxygen and hydrogen within individual water molecules, and hydrogen bonds forming between adjacent water molecules due to polarity.

Hydrogen Bond

A weak bond that forms between different polar molecules, such as between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another.

Cohesion

The attraction between like water molecules that causes water to bead and creates surface tension.

Adhesion

The attraction between water molecules and a different substance.

Capillary Action

The movement of water up plant stalks caused by adhesion and cohesion working together.

High Specific Heat

The property of water that requires a long time to heat up and a long time to cool down.

Universal Solvent

A property of water referring to its ability to dissolve ionic compounds effectively due to its polar nature.

Mixture

A physical combination of two or more substances that are not chemically combined, such as cinnamon and sugar.

Solution

A homogeneous mixture in which all parts are evenly distributed, consisting of a solute dissolved in a solvent.

Solute

The substance in a solution that gets dissolved (for example, sugar).

Solvent

The substance in a solution that does the dissolving (for example, water).

Suspension

A mixture containing undissolved particles alongside dissolved substances, such as blood containing dissolved salts and sugars in plasma with undissolved blood cells.

Non-Polar Substance

A substance lacking charged regions that rarely dissolves in water because it is not attracted to polar molecules (for example, oil).

CHONPS

The six most common elements in living things: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), and Sulfur (S), which make up $95\%$ of human body weight.

Organic Chemistry

The study of all chemical compounds containing bonds between carbon atoms.

Macromolecule

A very large organic molecule (biomolecule) made up of smaller subunits called monomers held together by chemical bonds.

Polymerization

The chemical process of joining monomers together to form a polymer.

Dehydration Synthesis

The process of building macromolecules by removing a water molecule to form chemical bonds.

Hydrolysis

The process of breaking down macromolecules by adding a water molecule to break chemical bonds.

Carbohydrates

Organic macromolecules composed of Carbon, Hydrogen, and Oxygen (CHO) in a $1\text{C}:2\text{H}:1\text{O}$ ratio that function as a primary source of short-term energy.

Monosaccharide

The monomer of carbohydrates consisting of a simple sugar, such as glucose ($C_6H_{12}O_6$).

Polysaccharide

A complex carbohydrate polymer made of many monosaccharides; examples include starch (stored energy in plants), cellulose (in plant cell walls), and glycogen (stored glucose in animal liver and muscles).

Lipids

Organic macromolecules composed of Carbon, Hydrogen, and Oxygen (CHO) made of glycerol and fatty acids; functions include long-term energy storage, insulation, protection, cell membrane structure, and chemical messengers.

Triglyceride

A lipid structure shaped like an "E", consisting of $1$ glycerol molecule bonded to $3$ fatty acid chains.

Saturated Fat

A lipid containing only single carbon-carbon bonds (C-C) in its fatty acid chains; typically found in animals and solid at room temperature.

Unsaturated Fat

A lipid containing one or more double carbon-carbon bonds (C=C) in its fatty acid chains; typically found in plants and liquid at room temperature.

Phospholipid

A membrane lipid made of $1$ polar, hydrophilic (water-loving) phosphate head and $2$ non-polar, hydrophobic (water-fearing) fatty acid tails.

Cholesterol

A lipid structured in ring shapes (hexagons) used to make steroid hormones and form part of the cell membrane.

Nucleic Acids

Organic macromolecules composed of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus (CHONP) that contain genetic information and assist in protein synthesis.

Nucleotide

The monomer of nucleic acids, consisting of a 5-carbon (pentose) sugar, a phosphate group, and a nitrogenous base (A, T, C, G, U).

Chemical Reaction

A process that changes one set of chemicals into another set by breaking chemical bonds and forming new ones.

Reactants

The starting substances that are changed during a chemical reaction.

Products

The substances made or produced by a chemical reaction.

Cellular Respiration Equation

The chemical reaction written as $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$, where glucose and oxygen act as reactants.

Bond Energy

The measure of energy in a chemical bond; energy is absorbed to break bonds and energy is released when bonds form.

Chemical Equilibrium

The condition reached when a chemical reaction proceeds in both directions at the same time and reactants and products are made at the same rate.

Activation Energy Graph

A reaction coordinate diagram showing the amount of free energy required for reactants to reach the transition state before proceeding to products.

Activation Energy

The minimum amount of energy that needs to be absorbed for a chemical reaction to start.

Exothermic Chemical Reaction

A reaction that releases more energy than it absorbs, giving off excess energy as heat or light; reactants have higher bond energies than products.

Endothermic Chemical Reaction

A reaction that absorbs more energy than it releases; reactants have lower bond energies than products (examples include photosynthesis and melting ice).

Catalyst

A substance that speeds up a chemical reaction by lowering the activation energy and increasing the reaction rate without being changed or consumed.

Enzyme

A specialized protein that acts as a biological catalyst to lower activation energy and speed up chemical reactions under controlled cellular conditions.

Enzyme Denaturation Conditions

Temperatures away from the ideal $37^\circ\text{C}$ or pH values outside the tolerance range of 6.5 - 7.5 that cause hydrogen bonds in an enzyme to break, altering its structure and function.