0415 Lipid and Carbohydrate metabolism: anabolic pathways Flashcards
Energy, reducing equivalents and starting materials for anabolism Increased [citrate] promotes lipid synthesis Formation of malonyl-CoA is regulated FA synthase – multienzyme complex PPP provides reduced cofactors for anabolism, anti-oxidants and ribose for nucleotides Pyruvate, amino-acids and glycerol enter gluconeogenesis Pool reactions identical to glycolysis Energetic/link reactions are distinct Regulation involves redox state and hormones
Anabolism is costly. Generally, what currency provides the energy required for most anabolic processes
ATP and sometimes GTP
Anabolism is a reductive process. What reducing agents provide the electrons required in anabolic processes
NADPH
Where does Fatty Acid synthesis occur. where does fatty acid breakdown occur
FA synthesis occurs in mitochondria. FA breakdown occurs in cytosol
What is the name of the multi sub-unit enzyme that synthesizes fatty acid
Fatty acid synthase
What is the committed step in fatty acid synthesis? What enzyme regulates this step
The first step. Conversion of acetyl CoA to malonyl-CoA (acetyl CoA carboxylase)
What hormones regulate the committed step in fatty acid synthesis and what are their actions (i.e. stimulate or inhibit)
Insulin - inhibits conversion of acetyl CoA to malonyl CoA. Adrenaline and glucagon stimulates this process
What is the name for the carrier molecule of malonyl CoA as it is synthesized into fatty acid
The carrier molecule is called the acyl carrier protein (ACP)
True or false: Anabolic pathways occur in the mitochondrial matrix and catabolic pathways occur in cytosol
False. Anabolic = cytosol. Catabolic = mitochondrial matrix
What molecule allosterically inhibits fatty acid breakdown
Malonyl CoA
What is the product of fatty acid synthesis
Palmitate
What molecules allosterically stimulate fatty acid synthesis
Citrate (palmitoyl CoA inhibits synthesis)
True or false, Insulin promotes fatty acid catabolism and glucagon/adrenaline promotes anabolism
False. Glucagon and adrenaline promote catabolism while insulin promotes anabolism
What are some roles of the pentose phosphate pathway
- Produce NADPH which reduces harmful reactive oxidative species
- produces ribose-5-phosphate (DNA and RNA)
What is the harmful oxidative species that NADPH from the pentose phosphate pathway elmiinates
Glutathione
Give some examples of systems/organs/tissues that use glucose as their primary source of energy
Brain, nervous system, ethryocytes, testes, renal medulla and embryonic tissue
