The effect of an enzyme on activation energy. Without affecting the free-energy change (∆G) for a reaction, an enzyme speeds the reaction by reducing its activation energy (EA). Source: Urry, Lisa A.. Campbell Biology (p. 155). Pearson Education. Kindle Edition. Campbell Biology Proteins, DNA, and other complex cellular molecules are rich in free energy and … Continue reading How Enzymes Speed Up Reactions?
Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Credit: Lissa Nilsson Source: https://www.artsy.net/artist/lisa-nilsson
Credit: Javier Herranz Casellas/Royal Society of Biology Source: Javier Herranz Casellas/Royal Society of Biology
Energy profile of an exergonic reaction. The “molecules” are hypothetical, with A, B, C, and D representing portions of the molecules. Thermodynamically, this is an exergonic reaction, with a negative ∆G, and the reaction occurs spontaneously. However, the activation energy (EA) provides a barrier that determines the rate of the reaction. Source: Urry, Lisa A.. … Continue reading The Activation Energy Barrier
Lipids may follow one of several pathways during metabolism. Glycerol and fatty acids follow different pathways. Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology When glucose levels are plentiful, the excess acetyl CoA generated by glycolysis can be converted into fatty acids, triglycerides, cholesterol, steroids, and bile salts. This process, called lipogenesis, creates lipids … Continue reading The Lipogenesis
ATP (adenosine triphosphate) contains the sugar ribose, with the nitrogenous base adenine and a chain of three phosphate groups (the triphosphate group) bonded to it. In addition to its role in energy coupling, ATP is also one of the nucleoside triphosphates used to make RNA. The bonds between the phosphate groups of ATP can be … Continue reading The Structure and Hydrolysis of ATP
When glucose is limited, ketone bodies can be oxidized to produce acetyl CoA to be used in the Krebs cycle to generate energy. Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology Organs that have classically been thought to be dependent solely on glucose, such as the brain, can actually use ketones as an alternative … Continue reading The Ketone Body Oxidation
During fatty acid oxidation, triglycerides can be broken down into acetyl CoA molecules and used for energy when glucose levels are low.Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology To obtain energy from fat, triglycerides must first be broken down by hydrolysis into their two principal components, fatty acids and glycerol. This process, called … Continue reading What is Lipolysis?
A triglyceride molecule (a) breaks down into a monoglyceride (b). Source: OpenStax Anatomy and Physiology OpenStax Anatomy and Physiology Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors. Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from … Continue reading The Lipid Metabolism