Lipids (fats) Flashcards
What is the etymology of the term “lipids,” and what does it signify about their characteristics?
The term “lipids” originates from the Greek word “lipos,” meaning “fat.” This etymology signifies that lipids are primarily characterized by their hydrophobic nature, being insoluble in water.
Name three lipid examples and briefly describe their primary functions in the body.
Three examples of lipids are fatty acids, triglycerides, and phospholipids. Fatty acids serve as energy sources, triglycerides function as storage molecules in adipose tissue, and phospholipids are essential components of cell membranes.
Differentiate between lipids that contain fatty acids and those classified as steroids.
Lipids containing fatty acids include triglycerides and phospholipids, which serve as energy sources and cell membrane components, respectively. Steroids, on the other hand, lack fatty acids and include molecules like cholesterol and sex hormones, serving roles in membrane structure and hormone signaling.
Define fatty acids and explain their solubility in water.
Fatty acids are long-chain hydrocarbon molecules with a carboxyl group. They are insoluble in water due to their hydrophobic nature, meaning they repel water molecules.
How do saturated and unsaturated fatty acids differ in terms of molecular structure and physical properties?
Saturated fatty acids contain only single carbon-carbon bonds and are solid at room temperature, while unsaturated fatty acids have one or more double bonds and are liquid at room temperature.
What distinguishes trans fats from cis fats, and what health risks are associated with trans fats?
Trans fats are formed by hydrogenation of natural cis fats and are associated with increased risk of cardiovascular disease due to their impact on cholesterol levels.
Discuss the composition and properties of natural fats and oils, using olive oil as an example.
Natural fats and oils consist of mixtures of saturated and unsaturated fatty acids. Olive oil, for instance, contains predominantly unsaturated fatty acids, making it liquid at room temperature.
What role do triglycerides play in the human body, and where are they primarily stored?
Triglycerides serve as the main lipid storage molecules in the body and are primarily stored in adipose tissue.
Describe the structure of phospholipids and their significance in cell membranes.
Phospholipids consist of glycerol, two fatty acids, a phosphate group, and a small polar molecule. They form the lipid bilayer of cell membranes, providing structural integrity and regulating cellular transport.
What is the primary structural feature of a steroid molecule, and provide an example of a steroid lipid.
Steroid molecules feature a characteristic four-ring hydrocarbon structure. Cholesterol is a prominent example of a steroid lipid.
Enumerate the functions of cholesterol in the human body and its dietary sources.
Cholesterol serves as a key component of cell membranes, is involved in the synthesis of steroid hormones and vitamin D, and is found in the diet from sources such as meats, milk, and eggs.
Name two examples of sex hormones classified as steroid lipids and their physiological roles.
Testosterone and estrogen are sex hormones that regulate reproductive functions and secondary sexual characteristics.
Explain the term “anabolic steroids” and list some of their potential side effects.
Anabolic steroids are synthetic derivatives of testosterone used illegally to enhance muscle mass. Side effects may include infertility, growth effects, fluid retention, gynecomastia, and liver damage.
What is the role of glucocorticoids produced by the adrenal glands, and provide an example of a glucocorticoid hormone.
Glucocorticoids regulate carbohydrate and protein metabolism in the body. An example is cortisol, also known as the “stress” hormone.
How are lipids classified based on their structure, and provide examples for each category.
Lipids are classified into those containing fatty acids (triglycerides, phospholipids) and those without (steroids such as cholesterol and sex hormones).
