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Lipids
A major group of organic molecules common to living systems.
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What are lipids composed of?
Carbon, hydrogen, oxygen and some contain other elements such as phosphorus and nitrogen.
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Why can lipids be dissolved in nonpolar organic solvents, such as alcohol, but no in water?
They have a lower oxygen to carbon ratio and are less polar
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What important functions do lipids provide?
Protection and insulation, help regulate many physiologic processes, form plasma membranes, store energy, and can be broken down and used as an energy source.
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What kinds of molecules are classified as lipids?
Fats, phospholipids, steroids, and prostaglandins
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Fats are a major type of ____.
Lipid
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Like carbohydrates fats are ingested and broken down by ____
Hydrolysis reaction in cells to release energy
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What role do lipids play in the body?
Protection, insulation, regulation, vitamins, structure, & energy
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How do lipids provide protection?
Fat surrounds and pads organs
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How do lipids provide insulation?
- Fat under the skin prevents heat loss.
- Myelin surrounds nerve cells and electrically insulates the cells from one another.
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How do lipids provide regulation?
- Steroid hormones regulate many physiologic processes.
- Prostaglandins help regulate tissue inflammation and repair.
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How do lipids provide vitamins?
- Fat-soluble vitamins are stored such as A, D, E, and K.
- How do lipids provide structure?
- Phospholipids and cholesterol are important components of the membranes of cells.
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How do lipids provide energy?
Lipids can be stored and broken down later for energy.
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Which fat makes up 95% of fats in the human body?
Triglycerides
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Triglycerides are sometimes called _____.
Triacylglycerols
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What do triglycerides consist of?
1 glycerol and 3 fatty acids.
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How are glycerides described?
- According to the number and kinds of fatty acids that combine with glycerol through dehydration reaction.
- Monoglycerides – 1
- Diglycerides – 2
- Triglycerides – 3
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Saturated fatty acids
- Contains only single covalent bonds between the carbon atoms.
- Beef, pork, whole milk, cheese, butter, eggs, coconut oil, and palm oil
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Unsaturated fatty acids
Has one or more double covalent bonds between carbon atoms.
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Monounsaturated fats
- Have one double covalent bond between carbon atoms.
- Olive and peanut oils
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Polyunsaturated fats
- Have two or more double covalent bonds between carbon atoms.
- Safflower, sunflower, corn, and fish oils
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Which fats are best and why?
Unsaturated fats because they don’t contribute to cardiovascular disease.
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Phospholipids
- Similar to triglycerides except that one fatty acid is replace by a phosphate molecule and nitrogen.
- Important structural components of the membranes of cells.
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Hydrophilic
Attracted to water
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Hydrophobic
Repelled by water
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Eicosanoids
A group of important chemicals derived from fatty acids.
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Prostaglandins, thromboxanes, and leukotrienes are what type of group?
Eicosanoids
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Where are eicosanoids made?
In most cells
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Why are eicosanoids important?
They are important regulatory molecules and help repair tissue, regulate hormones, blood clotting, reproductive function, and more.
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What are some important steroid molecules?
Cholesterol, bile salts, estrogen, progesterone, and testosterone
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