Not all amino acids directly enter the Tricarboxylic Acid (TCA) cycle. Amino acids are primarily used for protein synthesis in the body. However, they can also serve as an energy source. When they are metabolized for energy, amino acids undergo deamination to remove their amino group. The remaining carbon skeletons can enter metabolic pathways for energy production. These skeletons may enter the TCA cycle, but the entry point and process vary depending on the amino acid. Some may convert into TCA intermediates like alpha-ketoglutarate, succinyl-CoA, fumarate, or oxaloacetate, while others may feed into glycolysis or the ketone body formation pathways. Therefore, while not all amino acids directly participate in the TCA cycle, their breakdown products can contribute to the cycle or other energy-generating pathways depending on their type.

A polymer is like a big chain made of smaller parts called monomers. Imagine if you linked many paperclips together to form a long chain; each paperclip represents a monomer, and the whole chain is the polymer. Polymers are everywhere! Plastic bottles, rubber bands, and even DNA in our bodies are made of polymers. They're special because they can be designed to be really strong, stretchy, or even break down in the environment. Scientists work with polymers to create new materials for toys, medical devices, and eco-friendly packaging.

PVC pipe, known for its durability, low cost, and resistance to corrosion and chemicals, is widely used in both construction and home applications. In construction, it's primarily used for plumbing systems and sewage lines due to its water resistance and non-reactive properties, significantly reducing maintenance costs and increasing longevity. In home DIY projects, its versatility shines through in applications ranging from garden irrigation systems to creative furniture and storage solutions. Additionally, due to its lightweight nature, it's often used in crafting frameworks for lightweight structures and greenhouses. Innovatively, PVC pipes are also employed in hydroponic gardening systems, showcasing their utility in sustainable agriculture practices. Their adaptability, combined with the relatively easy installation process, makes PVC pipes a go-to choice for both professional contractors and homemakers aiming for practical and ingenious solutions.