24 Questions
What is the main difference between fats and polysaccharides as energy sources?
Fats are used for long-term energy needs, while polysaccharides are used for short-term energy needs.
Vertebrates store fat in specialized cells called adipocytes, located mainly in the liver.
False
What is the advantage of fats over polysaccharides in terms of energy production?
Fatty acids carry more energy per carbon because they are more reduced, thus containing more electrons to pull off and generate ATP.
Fatty acid catabolism converts the chemical potential energy of fats into ________ in ATP.
chemical potential energy
Match the following locations with their corresponding storage of fats.
Vertebrates = Adipocytes under the skin Plants = Seeds
What happens to dietary triglycerides during digestion and absorption in the small intestine?
They are broken down into fatty acids and absorbed.
The fat biosynthesis and degradation pathways are the same.
False
What is the significance of compartmentalization in fat biosynthesis and degradation pathways?
Compartmentalization is important in fat biosynthesis and degradation pathways.
What is the result of glycerol being activated by glycerol kinase?
Glycolysis is activated
Fatty acid transport into the mitochondria requires carnitine.
True
What is the product of fatty acid catabolism in the mitochondria?
Acetyl-CoA
Glycerol is converted to ________ in glycolysis.
Intermediate
Match the following terms with their descriptions:
Beta oxidation = Breakdown of fatty acids in the mitochondria Fatty acid catabolism = Conversion of fatty acids to acetyl-CoA Carnitine = Molecule required for fatty acid transport Palmitic acid = A type of fatty acid
What is the primary source of energy for fatty acid catabolism?
Acetyl-CoA
Fatty acid biosynthesis occurs in the cytoplasm.
True
What is the enzyme that activates glycerol at the expense of ATP?
Glycerol kinase
What is the advantage of glucose oxidation (glycolysis and TCA) for energy supply?
It's better for short-term energy supply
Malonyl-CoA, an early intermediate of fatty acid synthesis, activates carnitine acyltransferase I.
False
What is the purpose of malonyl-CoA in fatty acid metabolism?
Malonyl-CoA inhibits carnitine acyltransferase I, preventing fatty acid entry into mitochondria and blocking fatty acid breakdown while synthesis is occurring.
During β-oxidation of mono-unsaturated fatty acids, an isomerase is used to facilitate the process after ____________ rounds of β-oxidation.
three
In diabetic patients, the TCA cycle is converted to ketone bodies instead of acetate.
True
Match the following processes with their primary functions in fatty acid metabolism:
Glycolysis and TCA = Energy production from fatty acids β-Oxidation = Short-term energy supply Fatty acid synthesis = Conversion of acetyl-CoA to malonyl-CoA Ketone body formation = Produced in diabetic patients
What is the primary source of energy for seeds during germination?
Fatty acids and oils
The enzyme responsible for converting acetyl-CoA to malonyl-CoA during fatty acid synthesis is called _________________.
acetyl-CoA carboxylase (ACC)
Study Notes
Fats and Triglycerides
- Dietary triglycerides, regardless of plant or animal source, are composed of three fatty acid acyl chains and one glycerol molecule.
- Fats are an important source of energy, providing about one-third of our energy needs.
Advantages of Fats over Polysaccharides
- Fatty acids carry more energy per carbon due to their higher reduction state, resulting in more electrons available for ATP production.
- Fatty acids carry less water along because they are nonpolar.
Storage Locations of Fats
- In vertebrates, fats are stored in specialized cells called adipocytes, mainly located under the skin.
- In plants, fats are stored in seeds.
Fat Biosynthesis and Degradation Pathways
- The pathways for fat biosynthesis and degradation are different and compartmentalized.
Digestion, Mobilization, and Transport of Fats
- Dietary fatty acids are absorbed in the small intestine.
- Fats are transported and absorbed quickly.
Oxidation of Fatty Acids
- Fatty acids are oxidized through β-oxidation, producing energy.
- Mono-unsaturated fatty acids require an isomerase to bypass the first enzyme of β-oxidation.
Regulation of Fatty Acid Metabolism
- High glucose levels inhibit fatty acid breakdown by preventing fatty acid entry into mitochondria.
- Malonyl-CoA, an intermediate of fatty acid synthesis, inhibits carnitine acyltransferase I, blocking fatty acid breakdown.
β-Oxidation in Plants
- Seeds are rich in fatty acids, which are used as an energy source during germination.
Ketone Bodies
- Ketone bodies are formed when acetyl-CoA is converted to acetone, producing energy.
- This occurs in diabetic patients with high glucose levels.
Glycerol from Fats
- Glycerol from fats enters glycolysis through glycerol kinase, which activates glycerol at the expense of ATP.
Fatty Acids Conversion and Activation
- Fatty acids are converted to fatty acyl-CoA in the cytoplasm through a series of reactions.
- Fatty acyl-CoA is then transported into the mitochondria for β-oxidation.
Fatty Acid Transport into the Mitochondria
- Fatty acyl-CoA is converted to fatty acyl carnitine, which is transported into the mitochondria through a series of reactions.
- Only carnitine is transported back out of the mitochondria.
Explore the composition and benefits of fats, including their role as an energy source and advantages over polysaccharides.
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