chemistry part 3 lipids Flashcards
(7 cards)
lipids
Lipids
Lipids, or fats, are a large and diverse group of organic compounds (Table 2.5). They enter the body in the form of meats, egg yolks, dairy products, and oils. The most abundant lipids in the body are triglycerides, phospholipids, and steroids. Like carbohydrates, all lipids contain carbon, hydrogen, and oxygen atoms, but in lipids, carbon and hydrogen atoms far outnumber oxygen atoms, as illustrated by the formula for a typical fat named tristearin, which is . Lipids are insoluble in water but readily dissolve in other lipids and in organic solvents such as alcohol and acetone.
Triglycerides
The triglycerides (tri-glis′er-īdz), or neutral fats, are composed of two types of building blocks, fatty acids and glycerol. Their synthesis involves the attachment of three fatty acids to a single glycerol molecule. The result is an E-shaped molecule that resembles the tines of a fork (Figure 2.15a). Although the glycerol backbone is the same in all neutral fats, the fatty acid chains vary; this variation results in different kinds of neutral fats.
Found in fat deposits (subcutaneous tissue and around organs); protect and insulate the body organs; the major source of stored energy in the body.
-you just need to know that the fatty acids and the glycerols shape the triglycorides.
triglicerides: saturated fats andunsaturated fats.
Saturated fats have single bonds between carbon atoms. Their chains are straight, so they pack tightly and become solid at room temperature—like butter or animal fat.
Unsaturated fats have one or more double bonds between carbon atoms, which makes their chains bend. This prevents tight packing, so they stay liquid at room temperature—like olive oil or vegetable oils.
Fats with longer chains and more saturation are more likely to be solid and come from animals.Yes, that’s right! Unsaturated fats—especially monounsaturated fats (like those in olive oil) and polyunsaturated fats (like those in fish and nuts)—are considered the healthiest types of fats for your heart.
triglicerieds: how someone can make unsaturated fats unhealthy
Trans fats are artificial fats made by adding hydrogen to unsaturated fats (a process called hydrogenation) to make them more solid (like turning oil into margarine).
This changes the structure of the fat, making it act more like saturated fat, which:
Raises bad cholesterol (LDL)
Lowers good cholesterol (HDL)
Increases heart disease risk
Omega-3 fatty acids, found in fish like salmon and tuna, are a healthy type of unsaturated fat that:
Lower inflammation
Support heart health
May help reduce the risk of chronic diseases
last triglycerides are the bodys main scource of energy
Triglycerides are the body’s main form of stored fat and serve as its most abundant and concentrated source of energy. When triglycerides are broken down (oxidized), they release a significant amount of energy that the body can use. These fats are primarily stored in fat deposits beneath the skin and around internal organs. This fat storage has important functions: it helps insulate the body, maintaining body temperature, and it also protects internal organs from physical injury and heat loss.
phosopholipid
Phospholipids (fos′fo-lip″idz) are similar to triglycerides. The major difference is that a phosphorus-containing group is always part of the molecule and takes the place of one of the fatty acid chains. Thus, phospholipids have two instead of three attached fatty acids
So, the main difference is:
Triglyceride = glycerol + 3 fatty acids
Phospholipid = glycerol + 2 fatty acids + 1 phosphate group
This phosphate group makes phospholipids special because part of the molecule loves water (hydrophilic) while the fatty acid tails hate water (hydrophobic) — and that’s why they’re so important in forming cell membranes!
Because the phosphorus-containing portion (the “head”) bears a negative charge, phospholipids have special chemical properties and polarity. For example, the charged region is hydrophilic (“water loving”), meaning it attracts and interacts with water and ions. The fatty acid chains (the nonpolar “tail”) are hydrophobic (“water fearing”) and do not interact with polar or charged molecules. The presence of phospholipids in cell membranes allows cells to be selective about what may enter or leave.
steroids
Steroids are basically flat molecules formed of four interlocking carbon rings (see Figure 2.15c); thus, their structure differs quite a bit from that of other lipids. However, like fats, steroids are made largely of hydrogen and carbon atoms and are fat-soluble. The single most important steroid molecule is cholesterol. We ingest cholesterol in animal products such as meat, eggs, and cheese, and some is made by the liver, regardless of dietary intake.
cholesterol often gets a bad reputation, but it’s actually essential for several important processes in the body! Here’s a simple breakdown of what it does:
Cholesterol is crucial for cell membranes: It helps maintain the integrity and fluidity of cell membranes, making them stable and flexible. Without cholesterol, cell membranes wouldn’t function properly.
Cholesterol is the raw material for making essential molecules:
Vitamin D: The body uses cholesterol to make vitamin D when exposed to sunlight. Vitamin D is vital for bone health, immune function, and many other processes.
Steroid hormones: These are chemicals produced by glands such as the adrenal glands and gonads (ovaries and testes). They include hormones like estrogen, testosterone, and cortisol, all of which regulate essential body functions, including metabolism, stress response, and reproduction.
Bile salts: Cholesterol is used to make bile salts, which are necessary for digesting fats in the intestines.
Cholesterol is needed for homeostasis: This term refers to the body maintaining a stable internal environment. Steroid hormones, which are derived from cholesterol, play key roles in regulating various bodily functions like metabolism, immune response, and reproduction. Without these hormones, processes like reproduction (without sex hormones) and stress management (without corticosteroids) wouldn’t be possible.
Although cholesterol has a bad reputation in terms of causing arteriosclerosis (a condition where arteries get clogged with fatty deposits, leading to heart disease), it’s important to note that cholesterol itself is necessary for health. It’s the balance of different types of cholesterol (like LDL — “bad” cholesterol, and HDL — “good” cholesterol) that matters for cardiovascular health.
