Heterotrophic anabolism
Eating is not just "filling up the tank". With the nutrients from their diet, heterotrophic cells make their own proteins, their own membranes and their own reserves, investing ATP and reducing power in the process.
Building with what comes from the diet
After a soccer game, Jayden eats a chicken sandwich and a bowl of rice, but his muscle cells do not store these foreign molecules; they store human myosin and glycogen. How do cells manage to turn the biomolecules of other organisms into their own by investing energy? (We come back to this at the end of the page.)
Define heterotrophic anabolism and give two specific examples of anabolic processes in a human cell (protein synthesis, fatty acid synthesis, or glycogen synthesis),…
Define heterotrophic anabolism and give two specific examples of anabolic processes in a human cell (protein synthesis, fatty acid synthesis, or glycogen synthesis), stating what these processes consume (ATP, NADPH, and precursors).
To manufacture its proteins, a cell needs amino acids, energy, and information. Explain where a human cell obtains each of these three things.
To manufacture its proteins, a cell needs amino acids, energy, and information. Explain where a human cell obtains each of these three things.
During digestion, nutrients are broken down into small molecules and anabolism does the opposite. Give two examples of polymers that the human body makes from monomers…
During digestion, nutrients are broken down into small molecules and anabolism does the opposite. Give two examples of polymers that the human body makes from monomers coming from the diet and state which is the monomer of each one.
Gluconeogenesis: making glucose
After a carbohydrate-rich meal, insulin secretion increases. Explain what anabolic processes insulin activates in the liver, in muscle, and in adipose tissue, and what…
After a carbohydrate-rich meal, insulin secretion increases. Explain what anabolic processes insulin activates in the liver, in muscle, and in adipose tissue, and what happens to those same processes during the period between meals.
What role does the liver play in anabolism? Name two synthesis processes it carries out (glycogen, plasma proteins, cholesterol, fatty acids) and explain one of them…
What role does the liver play in anabolism? Name two synthesis processes it carries out (glycogen, plasma proteins, cholesterol, fatty acids) and explain one of them briefly.
Synthesis of glycogen and fatty acids
Explain what glycogen is, in which organs it is mainly synthesized, and from which precursor it is formed, stating whether the process consumes or releases energy.
Explain what glycogen is, in which organs it is mainly synthesized, and from which precursor it is formed, stating whether the process consumes or releases energy.
Reason why essential amino acids must be supplied through the diet while non-essential ones do not need to be, and explain what metabolic problem arises when a diet is…
Reason why essential amino acids must be supplied through the diet while non-essential ones do not need to be, and explain what metabolic problem arises when a diet is deficient in complete proteins.
The citric acid cycle as an amphibolic pathway
A person loses $5\ \text{kg}$ of body fat after months of diet and exercise. Explain what has happened metabolically to that adipose tissue (lipolysis and oxidation of…
A person loses $5\ \text{kg}$ of body fat after months of diet and exercise. Explain what has happened metabolically to that adipose tissue (lipolysis and oxidation of the fatty acids) and explain why most of the lost carbon leaves the body as exhaled $\text{CO}_2$.
Synthesis of amino acids and proteins
Heterotrophic anabolism uses carbon skeletons from metabolism and a source of nitrogen. Transaminations transfer amino groups between amino acids and keto acids: they make it possible to form non-essential amino acids. In humans, the essential ones must be obtained from the diet because they are not synthesized in sufficient quantity. A diet lacking complete proteins, with too little of even one essential amino acid, stops protein synthesis.
Protein synthesis is one of the processes that consume the most energy in the cell. State in which steps of the synthesis energy is spent (activation of the amino acids,…
Protein synthesis is one of the processes that consume the most energy in the cell. State in which steps of the synthesis energy is spent (activation of the amino acids, translation) and explain why a cell that makes many proteins needs to respire intensely.
Muscle proteins are degraded and resynthesized constantly even though the muscle does not grow. Explain what this protein turnover consists of and what implication it…
Muscle proteins are degraded and resynthesized constantly even though the muscle does not grow. Explain what this protein turnover consists of and what implication it has for energy expenditure at rest.