Which of the following is a characteristic of chemical bonds?. Shorter bonds are generally stronger than longer bonds. Covalent bonds often fall apart at physiological temperatures. The number of van der Waals bonds an atom can form is limited by the valence of that atom. - PowerPoint PPT Presentation
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Which of the following statements concerning the energetics of covalent bonds is FALSE?
A. Low activation energies are barriers that prevent spontaneous rearrangements of covalent bonds incellular systems.
B. A molecule linked together by weak covalent bonds hasa larger amount of free energy than a molecule linked together by strong covalent bonds.
C. A chemical reaction in which molecules are transformed into other molecules with less free energy generally proceeds slowly at physiological temperatures in the absence of a catalyst.
D. Enzymes speed up chemical reactions by lowering the activation energies needed to break old covalent bonds during molecular rearrangements.
Coupled chemical reactions are required to activate various biological “precursor” molecules. (Activated precursors store free energy that can be used later in biosynthetic reactions such as DNA or protein synthesis.) Which of the following terms describes this class of coupled chemical reactions?