Biomolecules, Chemical Bonding, and Cell Biology Vocabulary

Vocabulary flashcards covering the four major biomolecules, valence electrons, bonding, water properties, DNA structure, organelle functions, enzyme behavior, and membrane transport.

Carbohydrates

Biomolecules with a ~$1:2:1$ ratio of $C:H:O$, containing ring structures and many $OH$ groups, which provide quick energy, short-term storage, and cell structure.

Lipids

Biomolecules composed of $C$, $H$, and very little $O$, made of glycerol and fatty acid chains or ringed sterols, functioning in long-term energy storage, cell membranes, and hormones.

Proteins

Biomolecules composed of $C$, $H$, $O$, and $N$, consisting of amino acid monomers linked by peptide bonds ($C-N$) that function as enzymes, structural components, transporters, and motor molecules.

Nucleic Acids

Biomolecules composed of $C$, $H$, $O$, $N$, and $P$, made of nucleotide monomers (sugar, phosphate group, nitrogen base) that store genetic information and transfer energy.

Valence Electrons

Electrons located in the outermost shell of an atom that determine bonding, charge, and chemical reactivity.

Valence Electron Periodic Groups Table

A reference table listing standard periodic table group numbers, representative elements, and their corresponding valence electron counts.

Octet Rule

The chemical principle stating that atoms gain, lose, or share electrons to obtain a full outer shell of $8$ valence electrons.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid composed of deoxyribose sugar, phosphate groups, and nitrogen bases (Adenine, Thymine, Cytosine, Guanine) that stores genetic information.

A–T Base Pair

A nitrogen base pair in DNA held together by $2$ hydrogen bonds.

C–G Base Pair

A nitrogen base pair in DNA held together by $3$ hydrogen bonds.

Hydrogen Bond

An intermolecular attraction between a hydrogen atom attached to a highly electronegative atom ($O$, $N$, or $F$) and a nearby electronegative atom with a lone pair.

Amino Acids

The monomer building blocks of proteins, consisting of an amino group ($NH_2$), a carboxyl group ($COOH$), and a variable $R$-group side chain.

Sterols

A special type of lipid characterized by a four-ring structure (such as cholesterol) that stabilizes cell membranes and serves as precursors to steroid hormones.

Glycoproteins

Molecules composed of carbohydrates attached to proteins that function in cell recognition.

Glycolipids

Molecules composed of carbohydrates attached to lipids that function in cell recognition.

Ionic Bond

A chemical bond formed by the transfer of electrons between a metal and a nonmetal.

Covalent Bond

A chemical bond formed by the sharing of electrons between nonmetals.

Polar Bonds

Covalent bonds with unequal sharing of electrons, commonly involving bonds such as $O-H$, $N-H$, $C-O$, and $C=O$.

Nonpolar Bonds

Covalent bonds with equal sharing of electrons, commonly found in $C-H$ and $C-C$ bonds.

Cohesion

The property of water molecules sticking to other water molecules.

Adhesion

The property of water molecules sticking to other surfaces.

High Specific Heat

The property of water that enables it to resist changes in temperature.

Hydrolysis

A chemical reaction that breaks polymers down into monomers by adding water.

Dehydration Synthesis

A chemical reaction that builds polymers from monomers by removing water, forming bonds such as peptide, glycosidic, and ester bonds.

Central Dogma

The principal framework describing the directional flow of genetic information: $DNA \rightarrow RNA \rightarrow Protein$.

Cell Membrane

A selective barrier made of a phospholipid bilayer with embedded proteins acting as channels, pumps, and receptors.

Mitochondria

Cellular organelles responsible for cellular respiration and ATP energy production.

Ribosomes

Cellular structures responsible for protein synthesis, located freely in the cytoplasm or attached to the rough ER.

Rough Endoplasmic Reticulum (Rough ER)

Organelle studded with ribosomes that synthesizes proteins destined for export.

Smooth Endoplasmic Reticulum (Smooth ER)

Organelle that synthesizes lipids and performs cellular detoxification.

Golgi Apparatus

Organelle responsible for packaging, modifying, and shipping proteins.

Lysosomes

Organelles containing enzymes for intracellular digestion and recycling of materials.

Vacuoles

Cellular organelles used for storage.

Enzymes

Proteins that speed up chemical reactions by lowering activation energy.

Denaturation

The loss of an enzyme's or protein's 3D shape due to extreme temperature or pH, resulting in loss of function.

Passive Transport

The movement of substances across a cell membrane from high to low concentration without the expenditure of cellular energy.

Active Transport

The movement of substances across a cell membrane from low to high concentration requiring ATP energy.

Hypertonic Solution

A solution with a higher solute concentration than the cell, causing water to leave the cell and the cell to shrink.

Hypotonic Solution

A solution with a lower solute concentration than the cell, causing water to enter the cell and the cell to swell.

Isotonic Solution

A solution with an equal solute concentration relative to the cell, resulting in no net movement of water.