Fundamental Concepts in Anatomy & Physiology: Chemistry and Biomolecules

Chemistry Foundations for Anatomy & Physiology

Subatomic Particles of an Atom

Atoms are the basic units of matter, composed of three main subatomic particles:

• Protons: Positively charged particles located in the nucleus.

• Neutrons: Neutral particles also found in the nucleus.

• Electrons: Negatively charged particles orbiting the nucleus.

Example: A carbon atom has 6 protons, 6 neutrons, and 6 electrons.

Atomic Number and Atomic Mass

The atomic number is the number of protons in an atom's nucleus, which determines the element's identity. The atomic mass number is the sum of protons and neutrons in the nucleus.

• Atomic Number ($Z$): $Z = \text{Number of Protons}$

• Atomic Mass Number ($A$): $A = \text{Number of Protons} + \text{Number of Neutrons}$

Example: Oxygen has atomic number 8 and atomic mass number 16.

Valence Electrons and Their Purpose

Valence electrons are electrons in the outermost shell of an atom. They are crucial for chemical bonding and determine an atom's reactivity.

• Atoms with full valence shells are generally stable.

• Atoms with incomplete valence shells tend to form bonds to achieve stability.

Polar Molecules

A polar molecule has an uneven distribution of charge due to differences in electronegativity between atoms. This creates partial positive and negative regions.

• Example: Water (H2O) is a polar molecule because oxygen is more electronegative than hydrogen.

Dehydration Synthesis Reaction

Dehydration synthesis is a chemical reaction where two molecules are joined by removing a water molecule.

• Common in forming polymers like proteins and carbohydrates.

• Equation: $\text{Monomer}_1 + \text{Monomer}_2 \rightarrow \text{Polymer} + \text{H}_2\text{O}$

pH Scale

The pH scale measures the concentration of hydrogen ions in a solution, indicating its acidity or alkalinity.

• Ranges from 0 (most acidic) to 14 (most basic).

• Neutral pH: 7

• Equation: $\text{pH} = -\log_{10}[\text{H}^+]$

Nucleotides

Nucleotides are the building blocks of nucleic acids (DNA and RNA).

• Composed of a phosphate group, a five-carbon sugar (ribose or deoxyribose), and a nitrogenous base.

Inorganic Compounds

Inorganic compounds generally do not contain carbon-hydrogen bonds. Examples include water, salts, acids, and bases.

Isotopes

Isotopes are atoms of the same element with different numbers of neutrons, resulting in different atomic masses.

• Example: Carbon-12 and Carbon-14 are isotopes of carbon.

Types of Bonds

Atoms can form different types of chemical bonds:

• Ionic bonds: Transfer of electrons between atoms.

• Covalent bonds: Sharing of electrons between atoms.

• Hydrogen bonds: Weak attractions between polar molecules.

Macromolecules: Carbohydrates, Lipids, Proteins

There are three main types of biological macromolecules:

• Carbohydrates: Provide energy; building blocks are monosaccharides.

• Lipids: Store energy and form cell membranes; building blocks are fatty acids and glycerol.

• Proteins: Perform various functions; building blocks are amino acids.

Triglycerides

Triglycerides are a type of lipid made of one glycerol molecule and three fatty acids.

DNA Base Pairing

In DNA, bases pair in a complementary fashion:

• Adenine (A) pairs with Thymine (T)

• Guanine (G) pairs with Cytosine (C)

Saturated vs. Unsaturated Fats

Saturated fats have no double bonds between carbon atoms; unsaturated fats have one or more double bonds.

• Saturated fats are solid at room temperature.

• Unsaturated fats are liquid at room temperature.

Acids and Bases

Weak acids and weak bases only partially dissociate in water.

• Example: Acetic acid is a weak acid.

Vitamins Produced in the Skin

The skin produces Vitamin D when exposed to sunlight.

Building Blocks of Biomolecules

Biomolecule	Building Block
Carbohydrates	Monosaccharides
Lipids	Fatty acids & Glycerol
Proteins	Amino acids

Hydrogen Bonds in Water

Hydrogen bonds form between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another.

Enzymes

Enzymes are biological catalysts that speed up chemical reactions without being consumed.

• Most enzymes are proteins.

• They lower the activation energy required for reactions.

Location of Electrons and Protons in an Atom

Protons are located in the nucleus, while electrons orbit the nucleus in energy levels or shells.

Additional info: Some questions reference matching or short answer formats, but the above notes provide expanded academic context for each concept.