Questions and Answers
What is cholesterol specifically classified as?
a steroid
Which hormones are made from cholesterol?
estradiol and testosterone
Which of the following characteristics is not true for saturated fats?
Which fat has the least number of hydrogen atoms?
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Of what are phospholipids important components?
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What is the basic structure of a steroid?
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Besides its use in hormone production, for what does the body use cholesterol?
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What are the four classes of lipids and what is an example of each?
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Why have trans fats been banned from some restaurants?
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What is it about the structure of fatty acids that gives them their physical characteristics?
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In phospholipids, glycerol backbone is attached to two fatty acid molecules and one phosphate group.
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Fats have predominantly saturated fatty acids and oils have predominantly unsaturated fatty acids.
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Omega 3 is an essential fatty acid because it is not synthesized by the body.
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Unsaturated fatty acids can exist in cis and trans configuration.
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Cis fatty acids have kinks and are major constituents of liquid oils.
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Saturated fats can be hydrogenated to form saturated fatty acids.
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LDL is bad cholesterol and HDL is good cholesterol.
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Waxes are a class of lipids that constitute long chain alcohols esterified to long chain fatty acids.
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Facilitated diffusion is still a passive transport.
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Phospholipids in animals can be of only four types.
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Triglycerides have fatty acids esterified with glycerol backbone, and phospholipids are triglycerides where one fatty acid chain is replaced by a phosphate group.
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Choline, ethanol amine, serine, and inositol are four organic molecules that are attached to phosphate group in the phospholipids and only serine is negatively charged, others are neutral.
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Study Notes
Cholesterol and Hormones
- Cholesterol is classified as a steroid.
- Estradiol and testosterone are hormones derived from cholesterol.
Characteristics of Fats
- Saturated fats are incorrectly believed to dissolve easily in water.
- Unsaturated fat has the least number of hydrogen atoms compared to other fats.
Phospholipids
- Phospholipids are crucial components of the plasma membrane in animal cells.
- Their structure consists of a glycerol backbone linked to two fatty acids and one phosphate group.
Lipid Classes
- Lipids can be categorized into four classes:
- Fats (e.g., margarine)
- Waxes (e.g., coating on feathers)
- Phospholipids (e.g., cell membrane constituents)
- Steroids (e.g., cholesterol)
Trans Fats
- Trans fats are created by hydrogenating oils, increasing saturation and isomerization, leading to higher LDL levels.
- Some restaurants have banned trans fats due to health concerns.
Fatty Acid Structures
- The difference in physical characteristics among triglycerides is due to the structure of their fatty acids.
- Unsaturated and trans fats contain double bonds in their carbon chains, while saturated fats do not.
Fats and Oils
- Fats predominantly contain saturated fatty acids whereas oils contain predominantly unsaturated fatty acids.
Essential Fatty Acids
- Omega-3 fatty acids are essential as the body cannot synthesize them.
Configurations of Fatty Acids
- Unsaturated fatty acids can exist in both cis and trans configurations, with cis forming kinks that contribute to their state as liquid oils.
Hydrogenation
- Saturated fats can undergo hydrogenation to become saturated fatty acids.
Cholesterol Types
- LDL is classified as "bad" cholesterol and HDL as "good" cholesterol.
Waxes
- Waxes consist of long-chain alcohols esterified to long-chain fatty acids, differing from triglycerides where fatty acids are linked to glycerol.
Transport Mechanisms
- Facilitated diffusion is a type of passive transport.
Types of Phospholipids
- Major phospholipid types in animals include:
- Phosphatidylcholine (PtdCho)
- Phosphatidylethanolamine (PtdEth)
- Phosphatidylserine (PtdSer)
- Phosphatidylinositol (PtdIns)
Triglycerides and Phospholipids
- Triglycerides consist of fatty acids esterified with a glycerol backbone, while phospholipids have one fatty acid replaced with a phosphate group.
Organic Molecules in Phospholipids
- Four organic molecules attached to the phosphate group in phospholipids include choline, ethanolamine, serine, and inositol. Only serine possesses a negative charge, with the others being neutral.
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Description
Test your knowledge on lipids with these flashcards. This quiz covers key definitions, classifications, and characteristics of various lipids, including cholesterol and fatty acids. Perfect for exam preparation!
