CH 10 Metabolism EXAM 1 Flashcards
Metabolism (47 cards)
Define metabolism.
Metabolism is the sum of all the chemical reactions in a cell.
Describe anabolism.
Anabolism is the buildup of small molecules to create large molecules, requiring energy (endergonic). Examples include photosynthesis, DNA synthesis, and protein synthesis.
Explain catabolism.
Catabolism is the breakdown of large molecules into small molecules, releasing energy (exergonic). Examples include glycolysis and the Krebs cycle.
How do anabolism and catabolism differ?
Anabolism involves the buildup of small molecules into large molecules and is endergonic, while catabolism involves the breakdown of large molecules into small molecules and is exergonic.
What role do enzymes play in metabolism?
Enzymes are needed in both anabolism and catabolism as they speed up chemical reactions.
Describe dehydration synthesis.
Dehydration synthesis is a reaction that synthesizes a polymer by losing water, resulting in a longer polymer.
Explain hydrolysis.
Hydrolysis is a reaction that breaks down a polymer by using water to break a bond, adding a water molecule in the process.
How does energy change in anabolism?
In anabolism, energy is required, making it an endergonic process.
How does energy change in catabolism?
In catabolism, energy is released, making it an exergonic process.
Describe hydrolysis in the context of polymers.
Hydrolysis is the process of breaking down a polymer by using a water molecule to break a bond.
How do enzymes affect chemical reactions in the body?
Enzymes speed up reactions by acting as organic catalysts and lowering the activation energy required for a chemical reaction.
Define the characteristics of enzymes.
Enzymes are primarily made of proteins, speed up reactions, lower activation energy, have a unique shape and specificity, possess an active site for substrate binding, are not used up in reactions, can be reused, can be regulated, and are subject to denaturation.
What is the role of an active site in an enzyme?
The active site is the region on the enzyme where the substrate binds, facilitating the chemical reaction.
Explain the difference between apoenzyme and holoenzyme.
An apoenzyme is the inactive protein component of an enzyme, while a holoenzyme is the active form, consisting of the apoenzyme plus a cofactor.
How do cofactors and coenzymes assist enzymes?
Cofactors are non-protein molecules, often metal ions like iron or zinc, that assist enzyme function, while coenzymes are organic molecules, often vitamins, that help enzymes work properly.
Describe how enzymes are generally named.
Enzymes are typically named based on their substrate or the reaction they catalyze, such as lactase for lactose or polymerase for DNA.
What are exoenzymes and endoenzymes?
Exoenzymes are enzymes that act outside the cell, while endoenzymes function within the cell.
How can enzymes be regulated?
Enzymes can be regulated through various mechanisms, including the presence of inhibitors or activators that affect their activity.
What happens to enzymes during denaturation?
During denaturation, enzymes lose their unique shape and functionality, often due to changes in temperature or pH.
Describe the function of exoenzymes.
Exoenzymes are involved in breaking down large, complex molecules into smaller subunits that can be easily absorbed by the cell.
Define endoenzymes and their role in cellular processes.
Endoenzymes are enzymes that function inside the cell, catalyzing reactions necessary for normal cellular processes.
How do constitutive enzymes differ from regulated enzymes?
Constitutive enzymes, like those in glycolysis, are always present and ready to function, while regulated enzymes, such as the Lac operon in E. coli, are only produced or activated when needed.
Explain feedback or end-product inhibition.
Feedback or end-product inhibition occurs when the final product of a metabolic pathway blocks an early reaction, shutting down the entire series to prevent waste.
Describe competitive inhibition in enzyme activity.
In competitive inhibition, a normal substrate competes with a competitive inhibitor for the active site of an enzyme. If the substrate wins, the reaction proceeds; if the inhibitor wins, the reaction is blocked.
