Lipids, Fats, and Biochemistry

High-density lipoprotein (HDL) is known as 'good cholesterol' because it transports cholesterol from tissues back to the liver for excretion or recycling.

DNA (deoxyribonucleic acid) is a type of nucleic acid that carries genetic information.

Proteins are essential macronutrients that play a key role in building and repairing body tissues, including muscle.

Carbohydrates are the body's primary and preferred source of quick energy.

The plasma membrane is primarily composed of a phospholipid bilayer, which provides the structure and selective permeability of the cell.

Essential nutrients are defined as those that the body cannot synthesize on its own in sufficient quantities and must therefore be obtained through the diet.

In immunofluorescence, antibodies are conjugated with fluorescent dyes (fluorophores) to detect specific antigens within a sample under a fluorescence microscope.

The energy in food (and oil) is stored in the chemical bonds of the molecules. When these bonds are broken during digestion or combustion, energy is released.

Before DNA was confirmed as the genetic material, scientists believed proteins were the carriers of genetic information because of their structural complexity and the variety of their 20 amino acid building blocks.

Unsaturated fats, found in vegetable oils, nuts, and seeds, are beneficial for heart health when consumed in moderation. In contrast, saturated and trans fats can increase cholesterol levels and the risk of heart disease. Therefore, dietary guidelines recommend choosing unsaturated oils over solid fats.

Sprouting is a process that enhances the nutritional profile of seeds and legumes, significantly increasing their protein content and digestibility. Sprouts are widely consumed as a rich, low-fat source of plant-based proteins and vitamins.

Health organizations recommend limiting saturated fat intake because high consumption is linked to increased LDL cholesterol levels and a higher risk of cardiovascular disease. Unsaturated fats and essential fatty acids are considered healthier fats.

In traffic-light food labeling systems, red indicates that the product is high in a particular nutrient (such as fat, saturated fat, sugar, or salt) that we should try to limit. Green indicates low levels, and amber indicates medium levels.

Villi absorb monomers and small molecules such as amino acids, fatty acids, mineral ions, and vitamins. Large macromolecules like intact proteins cannot be absorbed by the villi and must first be digested into amino acids.

Fat is the most energy-dense macronutrient, providing 9 kilocalories (kcal) of energy per gram. In comparison, carbohydrates and proteins provide only 4 kcal per gram, while alcohol provides 7 kcal per gram.