Study GuideBiochemistry I–Introduction to Biological Energy Flow1. Enzyme CatalystsAlmost all biochemical reactions in living cells need help to occur efficiently. This help comes fromenzymes, which are specializedbiochemical catalysts.For example, the biological synthesis of ammonia does not happen on its own at a useful rate. Itrequires aspecific enzymeto make the reaction proceed properly.Most enzymes areproteins, and they act astrue catalysts. This means they:•Speed up chemical reactions•Arenot used upduring the reaction•Can carry out the same reactionover and over againBecause enzymes are so efficient and reusable, they make it possible for thousands of chemicalreactions to occur quickly and in a controlled way inside living cells.Key TakeawayEnzymes are protein catalysts that make life’s chemistry possible by speeding up reactions withoutbeing consumed in the process.2.Space and Time Links in the CellAt any given moment,thousands of chemical reactionsare happening inside a single cell. Even asimple bacterium must perform many tasks at the same time. It has to:•Copy its DNA•Make new enzymes•Break down carbohydrates to release energy•Produce building blocks for proteins and nucleic acids•Bring nutrients into the cell and remove waste productsAll of this happenssimultaneously and efficiently.Preview Mode
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