bio: Ch 3

Carbon

Element essential to organic molecules; forms diverse covalent bonds with H, O, N, and other C.

Hydrogen

Lightest element; bonds with carbon to create organic compounds; contributes to molecular structure.

Organic molecule

A molecule that contains carbon and typically hydrogen, forming the basis of life’s chemistry.

Functional group

A group of atoms that determines the characteristic chemical reactivity of a molecule.

Nonpolar (hydrophobic)

Regions or bonds that repel water and do not dissolve in polar solvents.

Polar (hydrophilic)

Regions or bonds with partial charges that dissolve in water.

Isomer

Compounds with the same molecular formula but different structures.

Dehydration synthesis

Reaction that forms polymers by removing water and linking monomers.

Hydrolysis

Reaction that breaks polymers into monomers by adding water.

Polymer

Large molecule made of many monomer units covalently linked.

Monomer

A single unit that can join other units to form a polymer.

Carbohydrate

Biological molecule for energy and structure, including sugars and polysaccharides.

Lipid

Hydrophobic molecules for long-term energy storage and membrane structure.

Protein

Polymer of amino acids with diverse roles in enzymes, structure, transport, and signaling.

Nucleic acid

Polymer of nucleotides that stores and transmits genetic information.

Monosaccharide

Simple sugar; the basic unit of carbohydrates.

Disaccharide

Carbohydrate formed from two monosaccharides (e.g., sucrose, maltose, lactose).

Polysaccharide

A complex carbohydrate made up of long chains of monosaccharide units linked together.

Glucose

Monosaccharide; blood sugar and monomer of starch, glycogen, and cellulose.

Fructose

Monosaccharide isomer of glucose found in fruits.

Galactose

Monosaccharide isomer; part of lactose.

Ribose

Five-carbon sugar in RNA.

Deoxyribose

Five-carbon sugar in DNA, lacking an oxygen atom.

Sucrose

Disaccharide; glucose + fructose; table sugar.

Maltose

Disaccharide; glucose + glucose.

Lactose

Disaccharide; glucose + galactose; milk sugar.

Starch

Plant polysaccharide for energy storage.

Glycogen

Animal polysaccharide for energy storage.

Cellulose

Plant polysaccharide that provides structural support in cell walls.

Chitin

Polysaccharide containing amino groups; in arthropod exoskeletons.

Triglyceride

Glycerol esterified with three fatty acids; primary form of fats and oils.

Saturated fatty acid

Fatty acid with no double bonds; typically solid at room temperature.

Unsaturated fatty acid

Fatty acid containing one or more double bonds; typically liquid at room temperature.

Trans fat

Unsaturated fat with trans double bonds; associated with health risks.

Phospholipid

Lipid with a phosphate group; forms cellular membranes.

Steroid

Lipids with four fused carbon rings; include hormones and cholesterol.

Cholesterol

Steroid component of membranes and a precursor to steroid hormones.

Testosterone

Steroid hormone involved in male secondary sexual characteristics.

Estrogen

Steroid hormone involved in female reproductive biology.

Enzyme

Protein that acts as a biological catalyst to speed up chemical reactions.

Denatured

Protein loses its 3D structure and function due to environmental changes.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

A protein’s local folding patterns, such as alpha helices and beta sheets.

Tertiary structure

Overall 3D folding of a protein driven by side-chain interactions.

Quaternary structure

Arrangement of multiple polypeptide chains into a functional protein.

Amino acid

Monomer of proteins; contains amino and carboxyl groups and a side chain.

Peptide

Bond between two amino acids formed by a peptide bond.

Polypeptide

Chain of many amino acids forming a protein.

Nucleotide

Monomer of nucleic acids; consists of a sugar, a phosphate group, and a base.

ATP

Adenosine triphosphate; main energy currency of cells.

DNA

Deoxyribonucleic acid; genetic material; usually double-stranded.

RNA

Ribonucleic acid; helps in protein synthesis; typically single-stranded.

Adenine

Purine base that pairs with thymine in DNA and with uracil in RNA.

Thymine

Pyrimidine base that pairs with adenine in DNA.

Cytosine

Pyrimidine base that pairs with guanine in DNA and RNA.

Guanine

Purine base that pairs with cytosine.

Uracil

Pyrimidine base that pairs with adenine in RNA (replaces thymine).

Base pairing

Specific hydrogen-bonding between bases: A-T (or A-U in RNA) and G-C.

Gene

Unit of heredity; a sequence of DNA that encodes a protein or RNA.

Double helix

Three-dimensional structure of DNA, two strands wound around each other.

Monomer

A single building block that can join others to form polymers.

Polymer

A large molecule formed by linking many monomers.

What element is the backbone of all organic molecules?

Carbon

What is the general name for a large molecule made of many repeating smaller units?

Polymer

What type of reaction involves the removal of a water molecule to link monomers together?

Dehydration synthesis

What term describes compounds with the same molecular formula but different structural arrangements?

Isomer

What reaction breaks polymers into monomers by adding water?

Hydrolysis

What is the basic monomer unit of carbohydrates?

Monosaccharide

Name a disaccharide formed from glucose and fructose.

Sucrose

Which plant polysaccharide is used for energy storage?

Starch

What structural polysaccharide is found in the cell walls of plants?

Cellulose

What specific type of covalent bond links monosaccharides together in a carbohydrate?

Glycosidic linkage

What characteristic makes lipids hydrophobic?

Their nonpolar nature

What is the primary form of fats and oils, consisting of glycerol esterified with three fatty acids?

Triglyceride

Which type of fatty acid contains one or more double bonds and is typically liquid at room temperature?

Unsaturated fatty acid

What lipid forms the primary structure of cellular membranes?

Phospholipid

What type of bond is formed between a fatty acid and glycerol in a lipid?

Ester linkage

What is the monomer unit that makes up proteins?

Amino acid

What is the term for a protein that has lost its specific three-dimensional shape and function?

Denatured

What is the primary function of an enzyme?

To act as a biological catalyst, speeding up chemical reactions

What specific bond links amino acids together in a polypeptide chain?

Peptide bond

What are the three components of a nucleotide?

A sugar, a phosphate group, and a nitrogenous base

polymer

A large molecule composed of repeating structural units called monomers, bonded together through covalent chemical bonds.

Macromolecules

Large molecules made up of smaller subunits (monomers), essential for biological functions, including proteins, nucleic acids, carbohydrates, and lipids.