Molecular Structures and Biomolecules Quiz

The number of atoms of each element in a molecule. It represents the relative proportions of each element.

Bonds formed when atoms share electrons to achieve a stable electron configuration.

Bonds formed when atoms transfer electrons to achieve a stable electron configuration. The transfer results in oppositely charged ions that attract each other.

The outermost energy level of an atom, containing the valence electrons that participate in chemical bonding.

Electrons in the outermost energy level of an atom, involved in chemical bonding.

A compound formed when two or more nonmetals share electrons.

A compound formed by the electrostatic attraction between oppositely charged ions. One atom loses electrons (metal) and the other gains electrons (nonmetal).

A molecule with a separation of electric charge, leading to a positive and a negative end. This results from unequal sharing of electrons in a covalent bond.

The ability of water to dissolve substances like sugar and salt due to its polar nature, which allows it to interact with the positive and negative charges of these compounds.

Hydrogen bonding occurs when a hydrogen atom is attracted to a highly electronegative atom, like oxygen in water. This leads to strong attractions between water molecules and a variety of properties like high boiling point and surface tension.

Water molecules can ionize into hydrogen ions (H+) and hydroxide ions (OH-) in a reversible reaction.

A solution is acidic when it has a higher concentration of hydrogen ions (H+) than hydroxide ions (OH-), resulting in a pH value below 7.

A solution is basic (alkaline) when it has a higher concentration of hydroxide ions (OH-) than hydrogen ions (H+), resulting in a pH value above 7.

A solution is neutral when the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-), resulting in a pH value of 7. Pure water is a neutral solution.

A scale that measures the acidity or basicity of a solution using a number from 0 to 14. Solutions with a pH below 7 are acidic, solutions with a pH above 7 are basic, and solutions with a pH of 7 are neutral.

Organisms must maintain a stable internal environment, including a balanced pH level, to survive and function properly. Organisms use buffers to resist changes in pH and maintain homeostasis.

A biological buffer system is a solution that resists changes in pH when small amounts of acid or base are added. It works by having a weak acid and its conjugate base present in the solution. These pairs can neutralize added acids (H+ ions) or bases (OH- ions) to maintain a stable pH.

One way a biological buffer works is by releasing hydrogen ions (H+) when the pH becomes too basic. This helps bring the pH back down to a more neutral level.

Another way a biological buffer works is by accepting hydrogen ions (H+) when the pH becomes too acidic. This helps neutralize the excess acid and raise the pH to a more neutral level.

The ability of an atom to form chemical bonds is determined by its valence electrons. These are the electrons found in the outermost shell of an atom.

A molecule is considered 'organic' if it contains both carbon (C) and hydrogen (H) atoms. Carbon's unique ability to form four bonds allows for diverse organic molecules.

A polar molecule has an uneven distribution of electrical charge. This happens because some atoms within the molecule are more electronegative (attracting electrons) than others.

A nonpolar molecule has an even distribution of electrical charge. The atoms within the molecule share electrons equally, resulting in no distinct areas of positive or negative charge.

Hydrophilic molecules are attracted to water. They typically have polar regions or charged groups, allowing them to form strong interactions with the polar water molecules.

Enzymes can speed up the rate of chemical reactions without being consumed or permanently changed by the reaction.

Enzymes are very specific, meaning each enzyme typically catalyzes only one type of reaction or works on a specific type of molecule called a substrate.

Low temperatures slow down enzyme activity. Enzymes work best at their optimal temperature, and too low of a temperature can reduce the rate of reactions.

High temperatures can denature enzymes, meaning they lose their specific shape and become inactive. This is because heat disrupts the bonds holding the enzyme's structure together.

Changes in pH levels, whether too acidic or too basic, can denature enzymes, disrupting their structure and affecting their activity.

Enzymes are a type of protein, which are large biomolecules made up of smaller units called amino acids.

Enzymes are not always decomposition reactions, they can also be involved in building up molecules (anabolism). They can accelerate both breakdown and synthesis processes.

The specific name of the enzyme used in the lab is catalase. The substrate for catalase is hydrogen peroxide (H2O2).

Lipids are a diverse group of organic molecules that are essential for various biological functions. They are characterized by their insolubility in water, due to their hydrophobic nature. Lipids include fats, oils, waxes, phospholipids, and steroids.

Saturated fats contain only single bonds between carbon atoms in their fatty acid chains. This results in a straight chain structure and a solid consistency at room temperature. Unsaturated fats have at least one double or triple bond between carbon atoms, leading to a bent chain structure and a liquid consistency at room temperature.

The R-group (side chain) of an amino acid is a unique chemical group that varies among different amino acids. It is responsible for the specific properties and functions of each amino acid. These variations in R-groups, which can be polar, nonpolar, acidic, or basic, influence the overall structure and function of proteins.

Proteins are complex macromolecules composed of long chains of amino acids linked by peptide bonds. They exhibit four levels of structural organization: (1) Primary structure: linear sequence of amino acids, (2) Secondary structure: local folding patterns like alpha-helix and beta-sheet, (3) Tertiary structure: three-dimensional shape of a single polypeptide chain, and (4) Quaternary structure: arrangement of multiple polypeptide chains.

Enzymes are biological catalysts that speed up the rate of chemical reactions without being consumed in the process. They do this by lowering the activation energy required for the reaction to occur.

Competitive inhibitors bind to the active site of an enzyme, competing with the substrate for binding. Noncompetitive inhibitors bind to a different site on the enzyme, causing a conformational change that alters the enzyme's activity.

The lock-and-key model suggests that the enzyme's active site has a specific shape that perfectly fits the substrate, like a key entering a lock. The induced-fit model proposes that the enzyme's active site is flexible and adapts its shape to fit the substrate more closely, leading to a better interaction between the two.

Enzymes are reusable catalysts, meaning they are not consumed during the reaction. They can catalyze multiple reactions without being permanently altered. Substrates are the reactants that bind to the enzyme's active site, and they are converted into products. After product formation, the enzyme is free to bind to another substrate molecule.