Biochemistry Foundations in Anatomy & Physiology

Vitamins Synthesized in the Skin

The skin plays a crucial role in the synthesis of certain vitamins, which are essential for various physiological processes.

• Vitamin D: The primary vitamin produced in the skin is Vitamin D. When exposed to ultraviolet (UV) radiation from sunlight, the skin converts 7-dehydrocholesterol to Vitamin D3 (cholecalciferol).

• Importance: Vitamin D is vital for calcium absorption, bone health, and immune function.

• Example: Individuals with limited sun exposure may be at risk for Vitamin D deficiency.

Building Blocks of Lipids, Carbohydrates, and Proteins

Macromolecules are constructed from smaller units known as building blocks, each with distinct roles in cellular structure and function.

• Lipids: Built from fatty acids and glycerol.

• Carbohydrates: Composed of monosaccharides (simple sugars) such as glucose.

• Proteins: Assembled from amino acids.

• Example: The protein hemoglobin is made from amino acids, while triglycerides are formed from fatty acids and glycerol.

Hydrogen Bonds in Water

Hydrogen bonds are weak interactions that play a significant role in the properties of water and biological molecules.

• Definition: A hydrogen bond is an attraction between a hydrogen atom covalently bonded to an electronegative atom (like oxygen) and another electronegative atom.

• Role in Water: Hydrogen bonds cause water molecules to stick together, leading to high surface tension, cohesion, and a relatively high boiling point.

• Example: Hydrogen bonding enables water to act as an excellent solvent for ionic and polar substances.

Enzymes

Enzymes are biological catalysts that accelerate chemical reactions in the body without being consumed in the process.

• Definition: Enzymes are proteins that lower the activation energy required for reactions.

• Function: They are highly specific for their substrates and can be regulated by inhibitors or activators.

• Example: Amylase breaks down starch into sugars in the digestive tract.

Electron Orbitals in Atoms

Electron orbitals describe the regions around an atom's nucleus where electrons are likely to be found.

• Definition: Orbitals are mathematical functions that describe the probability of finding an electron in a particular region.

• Types: Common orbitals include s, p, d, and f, each with distinct shapes and energy levels.

• Example: The first energy level contains one s orbital, while the second contains one s and three p orbitals.

Electron Organization in Atoms

Electrons are organized in atoms according to energy levels and sublevels, following specific rules.

• Energy Levels: Electrons fill the lowest available energy levels first (the Aufbau principle).

• Orbitals: Each orbital can hold a maximum of two electrons with opposite spins (the Pauli exclusion principle).

• Example: The electron configuration of carbon is 1s2 2s2 2p2.

Electron Organization Table

The following table summarizes the maximum number of electrons in each energy level and sublevel:

Additional info: The electron configuration rules are essential for understanding chemical bonding and reactivity in biological molecules.