第二章lab Organic Compounds and Cellular Metabolism

Vocabulary flashcards covering organic compounds (carbohydrates, lipids, proteins, nucleic acids), protein structural levels, metabolic pathways, ATP structure, and enzyme dynamics.

Carbohydrate

A water-soluble organic compound containing carbon, hydrogen, and oxygen in a ratio of $1:2:1$ ($C:H:O$) that functions to supply energy.

Monosaccharides

Simple sugars that serve as the basic units of carbohydrates, with examples including glucose, fructose, and galactose.

Disaccharides

Carbohydrates composed of two monosaccharide units, such as sucrose and lactose.

Polysaccharides

Complex carbohydrates formed by long chains of monosaccharides, such as starch and glycogen.

Lipids

Organic compounds containing carbon, hydrogen, and oxygen (with a lower proportion of oxygen than carbohydrates) that dissolve in non-polar solvents like alcohol or acetone.

Fats (Triglycerides)

Lipids composed of three fatty acids bonded to a glycerol molecule that provide energy and are located in subcutaneous tissue and around organs.

Saturated Fatty Acid

A fatty acid containing only single covalent bonds ($C-C$) between carbon atoms.

Unsaturated Fatty Acid

A fatty acid containing one or more double covalent bonds ($C=C$) between carbon atoms.

Phospholipid

A modified triglyceride consisting of two fatty acid groups and a phosphorus group, featuring a polar (hydrophilic) region and a nonpolar (hydrophobic) region, serving as the main structural component of cell membranes.

Steroids

A class of lipids, such as cholesterol, used in synthesizing sex hormones, adrenal cortical hormones, bile salts, and vitamin D.

Protein

Organic macromolecules containing carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur, constructed from basic building blocks called amino acids linked by peptide bonds.

Amino Acid

The structural building block of proteins, consisting of an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom, and a side chain designated as $R$ attached to a central carbon atom.

Peptide Bond

A covalent bond formed between amino acids in a dipeptide, tripeptide, or polypeptide chain.

Primary Structure

The structural level of a protein determined by the specific number, kind, and sequence arrangement of amino acids in a polypeptide chain.

Secondary Structure

The folding or bending of a polypeptide chain into helices or pleated sheets, driven by hydrogen bonds formed between amino acids.

Tertiary Structure

The three-dimensional shape resulting from secondary folding of helices or pleated sheets driven by interactions within the polypeptide and hydrogen bonds formed with water.

Quaternary Structure

The spatial arrangement and association of two or more individual polypeptide/protein subunits to form a functional unit.

Fibrous Proteins

Structural proteins that provide the framework for body tissues, including keratin, elastin, and collagen (e.g., hair).

Globular Proteins

Functional proteins that regulate chemical processes and bodily functions, including antibodies, hormones, and enzymes.

Denaturation

The process wherein hydrogen bonds in a protein are disrupted, altering its three-dimensional shape and rendering it nonfunctional.

Nucleic Acids

Organic macromolecules composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus, constructed from nucleotide units.

Nucleotide

The basic structural unit of nucleic acids, consisting of a pentose sugar, a phosphate group, and one of five nitrogenous bases.

Nitrogenous Bases

The five chemical bases that contribute to nucleotide structure: adenine ($A$), guanine ($G$), cytosine ($C$), thymine ($T$), and uracil ($U$).

Deoxyribonucleic Acid (DNA)

A double-stranded helical nucleic acid containing deoxyribose sugar and the bases adenine, guanine, cytosine, and thymine, which stores genetic material and provides instructions for protein synthesis.

Ribonucleic Acid (RNA)

A single-stranded nucleic acid containing ribose sugar and uracil (instead of thymine), found in both the nucleus and cytoplasm in three varieties: messenger RNA, transfer RNA, and ribosomal RNA.

Metabolism

The sum total of all chemical reactions occurring within a living organism, divided into catabolism and anabolism.

Hydrolysis

A catabolic reaction that uses water to break chemical bonds, breaking down complex organic molecules into simpler end products and releasing energy.

Dehydration Synthesis

An anabolic reaction (condensation) that builds complex organic molecules from simpler products using enzymes and energy from catabolism, releasing water in the process.

Adenosine Triphosphate (ATP)

A three-part molecule consisting of adenine, ribose sugar, and three phosphate molecules in a chain, functioning as a temporary energy repository that releases free energy when phosphate bonds are broken.

Enzyme

A biological catalyst that lowers the energy of activation for a chemical reaction, typically ending with the suffix "-ase" (e.g., amylase, lipase).

Enzyme-Substrate Complex

The temporary structure formed when an enzyme orients the substrate into proper position for a reaction to proceed, increasing reaction probability.

Optimum Temperature of Human Enzymes

The temperature ($40^\circ\text{C}$) at which an intact human enzyme achieves maximum protein flexibility and rate of reaction, compared to normal body temperature ($37^\circ\text{C}$).

Optimum pH for Human Enzymes

The pH range ($6\text{--}8$) where most human enzymes function most efficiently before denaturing at higher acidity or basicity.

Cellular Respiration Locations

Glycolysis occurs in the cytosol, whereas aerobic cellular respiration (intermediate stage, citric acid cycle, and electron transport system) occurs in the mitochondria.