Human Body Chemistry and Macromolecules: Key Concepts and Structures

Chemical elements of the human body

Main elements include Carbon (C), Oxygen (O), and Hydrogen (H).

Sodium chloride (NaCl)

A molecule formed by the ionic bond between Sodium (Na) and Chloride (Cl) ions.

Water (H2O)

A molecule consisting of two Hydrogen (H) atoms and one Oxygen (O) atom, connected by covalent bonds.

Ionic bond

A bond formed through the attraction between oppositely charged ions.

Cation

An ion with a positive charge, such as Sodium (Na+).

Anion

An ion with a negative charge, such as Chloride (Cl-).

Electrolytes

Ions in solution that conduct electricity.

Covalent bond

A bond formed when two or more atoms share electrons.

Polar covalent bond

A type of covalent bond where electrons are shared unequally, resulting in partial charges.

Hydrogen bond

A weak bond formed between molecules due to the attraction of oppositely charged parts.

Hydrophilic

Substances that dissolve easily in water, such as NaCl.

Hydrophobic

Substances that do not dissolve easily in water, such as fats and oils.

Metabolism

The sum of all chemical reactions occurring in the body.

Chemical reaction

A process where new bonds are formed and old bonds are broken, involving changes in energy.

pH

A measure of the acidity or basicity of a solution.

Buffer systems

Systems that help maintain pH homeostasis in the body.

Macromolecules

Large molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Organic compounds made of monosaccharides, disaccharides, and polysaccharides.

Proteins

Macromolecules that perform various functions and have complex structures, which can denature.

Lipids

A group of macromolecules that include triglycerides, phospholipids, and steroids.

Nucleic Acids

Biomolecules that include DNA and RNA, essential for genetic information.

ATP

A molecule that carries energy within cells, playing a critical role in metabolism.

Endergonic reaction

Anabolic reactions where energy is absorbed when chemical bonds are formed.

Exergonic reaction

Catabolic reactions where energy is released when chemical bonds are broken.

Chemical Reactions

Occur slowly; the rate of reaction can be increased with a catalyst.

Catalyst

Lowers the activation energy and brings substrates together.

Acid

Increases the concentration of H+ ions in solution.

Base

Removes H+ from solution (accepts H+ ions).

Bicarbonate (HCO3-)

An important buffer in the human body that binds excess H+ ions in solution.

Normal pH of arterial blood

7.35-7.45; 7.4 is the midpoint.

Organic Compounds

Contain carbon atoms and include macromolecules such as carbohydrates, proteins, lipids, and nucleic acids.

Monosaccharides

Simple sugars such as glucose.

Disaccharide

Two monosaccharides, examples include sucrose and lactose.

Polysaccharides

Multiple monosaccharides, such as glycogen which is the storage form of glucose.

Protein Functions

Determined by proteins produced by a cell; includes enzymes, motor proteins, antibodies, hormones, and cell surface receptors.

Amino Acids

20 individual building blocks of proteins.

Peptide Bonds

Bonds that form between amino acids to create polypeptides.

Primary structure

Unique sequence of amino acids in a protein.

Secondary structure

Folding/twisting of neighboring amino acids in a protein.

Tertiary structure

3-dimensional shape of a polypeptide, allowing it to carry out a specific function.

Quaternary structure

Arrangement of multiple polypeptide chains.

Denaturation

Loss of protein tertiary structure due to high temperatures and low pH, leading to loss of function.

Triglycerides

Three fatty acid chains bonded to a glycerol molecule, a highly concentrated form of chemical energy.

Phospholipids

Two fatty acid chains bonded to a phosphate group, key components of cell membranes.

Steroids

Synthesized from cholesterol, involved in cell membrane structure and include steroid hormones like estrogen and testosterone.

Gene

Segment of DNA.

RNA (Ribonucleic Acid)

Single stranded nucleic acid.

DNA (Deoxyribonucleic Acid)

Double stranded nucleic acid that stores genetic information.

Adenosine Triphosphate (ATP)

Energy stored in the bonds of ATP; energy is released when the third phosphate group is removed.