Biochemistry and Organic Molecules in Human Physiology

What is biochemistry?

The study of the molecules that compose living organisms.

What are the two categories of organic compounds?

Carbohydrates, fats, proteins, and nucleic acids (organic); vitamins, minerals, electrolytes, and water (inorganic).

What percentage of the body is constituted by minerals?

About 4%.

What are electrolytes?

Mineral salts that ionize in water and form solutions capable of conducting an electric current.

What is the difference between anion and cation?

An anion has a net negative charge, while a cation has a net positive charge.

What is the significance of water's solvency?

Water is called the universal solvent because it can dissolve other chemicals.

What are hydrophilic and hydrophobic substances?

Hydrophilic substances dissolve in water, while hydrophobic substances do not.

What is the role of water in chemical reactivity?

Water ionizes into H+ and OH- and is needed for hydrolysis and dehydration synthesis reactions.

What is thermal stability in relation to water?

Water helps stabilize the internal temperature of the body.

What is the pH scale?

A logarithmic measure of hydrogen ion concentration; a pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

What are buffers and their function in the body?

Buffers, such as bicarbonate and phosphate, resist changes in pH and help maintain physiological function.

What are the two types of chemical reactions?

Decomposition reactions (large molecules break down) and synthesis reactions (small molecules combine to form larger ones).

What is the role of enzymes in chemical reactions?

Enzymes lower the activation energy required for reactions to occur.

What is metabolism?

The sum of all chemical reactions in the body, including catabolism (energy-releasing) and anabolism (energy-storing).

What are macromolecules?

Very large organic molecules with high molecular weights, including proteins, carbohydrates, and lipids.

What are carbohydrates and their primary function?

Hydrophilic organic molecules that serve as a quickly mobilized source of energy.

What are monosaccharides?

Single sugar molecules, such as glucose, galactose, and fructose.

What are disaccharides and give examples?

Sugar molecules composed of two monosaccharides; examples include sucrose (table sugar) and lactose (milk sugar).

What are polysaccharides and their types of interest in humans?

Long chains of glucose; types include glycogen (energy storage in animals), starch (energy storage in plants), and cellulose (structural molecule in plant cell walls).

What are lipids?

Hydrophobic organic molecules that include fats, oils, and steroids, with a high ratio of hydrogen to oxygen.

What is the primary structure of proteins?

The amino acid sequence of a protein, which is encoded by genes.

What is denaturation in proteins?

An extreme, nonfunctional change in a protein's shape due to external factors.

What are antibodies?

Proteins that play a role in immunity by recognizing and neutralizing pathogens.