Biological Molecules Lecture Review

Vocabulary flashcards covering key concepts from lectures on biological molecules, including their types, structures, functions, and related processes.

Inorganic molecules

Molecules that lack carbon, play important roles in metabolism, and make up only 1.5% of an organism's mass (excluding water).

Organic molecules

Molecules that contain carbon, are necessary for life, and are generally larger and more complex than inorganic molecules (macromolecules).

Macromolecules

Large, complex organic molecules, comprising four main families: Carbohydrates, Lipids, Proteins, and Nucleic acids.

Carbon atom

Makes four covalent bonds with four same or four different atoms or molecules.

Carbon Chains

Can vary in length, be unbranched or highly branched, have double bonds, or be arranged in rings.

Isomers

Have the same number and type of atoms (same molecular formula) but differ in their arrangement, resulting in different structure and function.

Structural Isomers

Isomers that have the same number and types of atoms but differ in the branching of the carbon skeleton.

Geometric Isomers

Isomers that have the same number and type of atoms but differ in the orientation of atoms around a double bond (trans vs. cis).

Enantiomers (Mirror Images)

Isomers that have the same number and type of atoms but are arranged in a mirror image around a central carbon atom.

Functional groups

Atoms or molecules attached to a carbon chain that are associated with specific chemical properties.

Hydrocarbon

The simplest functional group, consisting of a hydrogen atom attached to a carbon chain.

Hydroxyl group

A functional group consisting of a hydrogen and oxygen bonded to a carbon, characteristic of alcohols.

Carbonyl group

A functional group consisting of oxygen linked to carbon by a double bond, found in aldehydes and ketones.

Carboxyl group

A functional group where carbon is double bonded to an oxygen and a hydroxyl group, acting as an acid.

Amino group

A functional group consisting of nitrogen and two hydrogen atoms bonded to a carbon, found in amino acids (proteins).

Phosphate group

A functional group consisting of a phosphorus atom bonded to four oxygen atoms, found in DNA and ATP.

Methyl group

A functional group consisting of a carbon bonded to three hydrogen atoms, affecting the expression of genes (epigenetics).

Monomer

One unit or one building block.

Polymer

A large molecule made by linking many monomers together (a macromolecule).

Dehydration reaction

A reaction that removes a water molecule, resulting in the linking of two shorter polymers.

Hydrolysis

A reaction that breaks bonds within a polymer by the insertion of water.

Carbohydrates

Biological molecules functioning in energy, energy storage, and structural support; the simplest unit is a monosaccharide.

Monosaccharide

Simple sugars, the simplest carbohydrates, consisting of one sugar unit.

Fructose

A monosaccharide commonly found in fruit.

Ribose and Deoxyribose

Monosaccharides that are building blocks for nucleic acids.

Glucose

A monosaccharide that is a primary energy source and precursor of many organic molecules.

Disaccharides

Carbohydrates formed by a dehydration synthesis reaction of two monosaccharides.

Lactose

A disaccharide (milk sugar) made of glucose plus galactose.

Sucrose

A disaccharide (table sugar) made of glucose plus fructose.

Maltose

A disaccharide (found in beer) made of glucose plus glucose.

Polysaccharides

Complex carbohydrates consisting of many sugar units covalently linked, used for energy storage or structural roles.

Glycogen

A polysaccharide used for energy storage in animal tissues.

Starch

A polysaccharide used for energy storage in plants.

Cellulose (Fiber)

A polysaccharide that makes up the structure of plant cell walls.

Lipids

Hydrophobic biological molecules whose functions include energy, energy storage, cell membranes, organ protection, insulation against cold, and steroid hormones; the simplest unit is a fatty acid chain.

Hydrophobic

A property meaning 'does not dissolve in water'.

Fatty acid chain

The simplest unit of a lipid, varying in length from 8-48 carbon atoms.

Fats (Triglycerides)

Lipids consisting of three fatty acid chains linked to one glycerol molecule; used for energy, energy storage, organ protection, and insulation.

Oils

Fats that are liquid at room temperature.

Phospholipids

Lipids that make up cell membranes, structured with a hydrophilic glycerol and phosphate group head and two hydrophobic fatty acid tails.

Sterols

Lipids made up of four interconnected carbon rings, components of cell membranes and steroid hormones (e.g., cholesterol, estrogen, vitamin D).

Waxes

Lipids consisting of a fatty acid chain linked to an alcohol group, more water resistant than fats, preventing water loss in plants and waterproofing feathers.

Saturated Fats

Fats with single carbon bonds in their fatty acid chains, saturated with hydrogen atoms, typically solid at room temperature, and can increase bad cholesterol.

Unsaturated Fats

Fats with double carbon bonds in their fatty acid chains, creating one or more kinks, typically liquid at room temperature, and not harmful in moderation.

Hydrogenated Fats

Unsaturated oils that have been artificially modified by adding hydrogen to create saturated bonds, preventing separation, increasing shelf-life, and raising bad cholesterol.

Trans Fats

Fats with artificially added hydrogen atoms that cause a shift in the arrangement from cis to trans position, increasing bad cholesterol and decreasing good cholesterol, and recognized as very harmful to health.

Omega-3 Fats

Fats with a double bond between the 3rd and 4th carbon from the end of the chain, beneficial for health by increasing good cholesterol.

Hydrophilic

A property meaning 'attracted to water'.

Cholesterol

A type of sterol that is a component of cell membranes in animals and a precursor for steroid hormones.

Proteins

Biological molecules with diverse functions including structural, metabolic (enzymes), transport, movement, hormones, immune system roles, and nutrition; the simplest unit is an amino acid.

Amino acid

The simplest unit (monomer) of a protein; there are 20 types.

Peptide bond

A covalent bond formed by a dehydration reaction linking the amino group of one amino acid to the carboxyl group of another.

Essential amino acids

Nine amino acids that humans must ingest in their diet because they cannot synthesize them.

Primary structure (Protein)

A chain of amino acids, with the sequence dictated by the gene.

Secondary structure (Protein)

The alpha helical coil or beta pleated sheet arrangement of a protein resulting from hydrogen bonding between amino acids.

Tertiary structure (Protein)

The complex three-dimensional shape of a protein.

Quaternary structure (Protein)

The complexing of two or more polypeptide chains to form globular or fibrous proteins.

Denaturation

The disruption of a protein’s shape, leading to a loss of its normal functioning, often irreversibly, caused by factors like high temperatures, changes in pH, salt, or chemicals.

Enzymes

Protein catalysts that speed up chemical reactions by lowering the energy needed for the reaction, are specific, and are not used up or changed.

Substrate

The reactant molecule that specifically binds to the three-dimensional shape of an enzyme.

Nucleic Acids

Biological molecules whose functions include storage and transfer of hereditary information (DNA), transport of hereditary information and protein synthesis (RNA), and energy (ATP); the simplest unit is a nucleotide.

Nucleotide

The simplest unit (monomer) of a nucleic acid, consisting of a five-carbon sugar (ribose or deoxyribose), a nitrogen-containing base, and one to three phosphate groups.

DNA (Deoxyribonucleic acid)

A nucleic acid that stores genetic information, structured as two long strands held together by hydrogen bonding to form a double helix.

RNA (Ribonucleic acid)

A nucleic acid that functions in the transfer of inheritable information and the synthesis of proteins, typically a single, shorter chain.

ATP (Adenosine triphosphate)

A nucleic acid that is essential for cellular energy production, consisting of a ribose sugar, an adenine nitrogen base, and three phosphates.

Double helix

The characteristic structure of DNA, formed by two long strands held together by hydrogen bonding.

Guanine (G)

A nitrogenous base found in DNA, which pairs with Cytosine (C).

Adenine (A)

A nitrogenous base found in DNA, which pairs with Thymine (T).

Cytosine (C)

A nitrogenous base found in DNA, which pairs with Guanine (G).

Thymine (T)

A nitrogenous base found in DNA, which pairs with Adenine (A).

Uracil (U)

A nitrogenous base found in RNA, replacing Thymine (T).

ATP structure

Consists of a ribose sugar, an adenine nitrogen base, and three phosphates, serving as the primary energy currency of the cell.