BIO 93 Lecture Nomenclatures

chemical bonds

Forces that hold atoms together to form molecules or compounds.

hydrogen bond

A weak attraction between a hydrogen atom (already bonded to a highly electronegative atom like oxygen or nitrogen) and another electronegative atom.

covalent bond

A strong bond formed when two atoms share one or more pairs of electrons.

ionic bond

A bond formed when one atom transfers an electron to another, resulting in oppositely charged ions that attract each other.

elements

Pure substances made of only one type of atom. Each element is defined by its number of protons (atomic number).

atoms

The smallest unit of an element that still retains the properties of that element. Made up of protons, neutrons, and electrons.

molecules

Two or more atoms bonded together. They can be of the same element (e.g., O₂) or different elements (e.g., H₂O).

compound

A substance formed when two or more different elements are chemically bonded together (e.g., NaCl, H₂O).

hydration shell

The layer of water molecules that surrounds a dissolved ion or molecule in solution, helping it stay in solution.

hydrophobic

"Water-fearing" – describes substances that do not dissolve or mix well with water (e.g., oils, fats).

hydrophilic

"Water-loving" – describes substances that dissolve easily in water or form hydrogen bonds with it (e.g., salts, sugars).

solvent

The substance that does the dissolving (e.g., water).

solute

The substance that gets dissolved (e.g., salt).

solution

A homogeneous mixture of solute and solvent (e.g., saltwater).

pH

A scale (0–14) that measures how acidic or basic a solution is.

• pH < 7: Acidic

• pH = 7: Neutral

• pH > 7: Basic (alkaline)

buffer

A substance that resists changes in pH by accepting or donating H⁺ (protons) as needed.

hydroxide ion

A negatively charged ion made of one oxygen and one hydrogen atom. Common in basic (alkaline) solutions

proton

A hydrogen ion that has lost its electron, essentially just a proton. It determines the acidity of a solution.

Evolution

The process by which populations of organisms change over generations through variations in heritable traits and natural selection

Adaptation

A characteristic that enhances an organism's ability to survive and reproduce in a specific environment.

Ecosystem

A community of living organisms interacting with their physical environment, including both biotic and abiotic components.

Genes

Units of heredity that contribute to an organism's traits and characteristics, passed from parents to offspring.

DNA

The hereditary material in organisms that carries genetic information.

Emergent Properties

Characteristics of a system that arise from the interactions among its components, which are not present in the individual parts.

carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen that serve as a major energy source for living organisms and play key roles in structural components.

lipids

A diverse group of hydrophobic organic molecules, including fats, oils, and steroids, that are essential for energy storage, membrane structure, and signaling in organisms.

proteins

Large biomolecules composed of one or more chains of amino acids, essential for various functions such as catalyzing biochemical reactions, providing structural support, and regulating processes in living organisms.

functional group

specific atom or group of atoms within a molecule that is responsible for its characteristic chemical properties and reactivity

polymer

A substance made of large molecules formed by the repeated linking of small molecules (monomers)

monosaccharides 

Simple sugars that are the basic building blocks of carbohydrates. They cannot be broken down into smaller sugars

disaccharides

Carbohydrates made of two monosaccharide units linked together by a covalent bond.

Polysaccharides

Large carbohydrates made of many monosaccharide units linked together. They serve as energy storage or structural materials

saturated fats

Fats that have no double bonds between carbon atoms in their fatty acid chains. They are typically solid at room temperatures

unsaturated fats

Fats that have one or more double bonds in their fatty acid chains. These are usually liquid at room temperature.

• Monounsaturated: One double bond

• Polyunsaturated: Two or more double bonds

phospholipids

A type of lipid molecule that is a major component of cell membranes. Phospholipids have a hydrophilic (water-attracting) “head” containing a phosphate group, and two hydrophobic (water-repelling) “tails” made of fatty acids. This unique structure allows them to form bilayers that create the membrane barrier in cells.

steroids

A class of lipids characterized by a structure of four fused carbon rings. Unlike fats and phospholipids, steroids don’t have fatty acid tails. They serve various roles, including hormones and structural components of membranes.

amino acids

The basic building block of proteins, consisting of an amino group, carboxyl group, hydrogen atom, and a variable R group attached to a central carbon.

nucleic acids

Large biomolecules (DNA or RNA) made of nucleotide chains that store and transmit genetic information.

Ribonucleic Acid (RNA)

A nucleic acid containing the sugar ribose, involved in protein synthesis and gene regulation

Sugar-phosphate backbone

The repeating chain of sugar and phosphate groups in nucleic acids that forms the structural framework of DNA and RNA strands

phosphodiester linkage

A chemical bond that connects the sugar of one nucleotide to the phosphate of the next in nucleic acids

Purine

A type of nitrogenous base in nucleotides with a two-ring structure.
Examples: Adenine (A) and Guanine (G)

Pyrimidine

A type of nitrogenous base in nucleotides with a single-ring structure.
Examples: Cytosine (C), Thymine (T) in DNA, and Uracil (U) in RNA.

R group

The side chain attached to an amino acid that determines its chemical properties and behavior.

Polypeptide

A chain of amino acids linked by peptide bonds that folds into a functional protein.

Nonpolar

Molecules or parts of molecules that do not mix well with water; usually hydrophobic (water-repelling)

Polar

Molecules or parts of molecules that have a partial positive and negative charge and can interact with water (hydrophilic).

Hydrophobic

"Water-fearing" — describes nonpolar molecules or regions that repel water.

Hydrophilic

"Water-loving" — describes polar molecules or regions that interact well with water.

Chaperone protein

A protein that assists other proteins in folding correctly without forming incorrect structures

Ubiquitin

A small protein that tags damaged or unneeded proteins to signal their degradation

Proteasome degradation

A process where proteins tagged with ubiquitin are broken down into smaller peptides by the proteasome, a protein complex.