①物质运输是一个耗能过程,请举例说明有哪些能量来源? 答:①自由能;②ATP;③光能;④磷酸烯醇式丙酮酸;⑤动力势(协同) What is the advantage of having an extracellular signal transmitted by a cascade of sequential events? Answer@2: Transduction of an extracellular signal via a cascade of sequential events is advantageous because of the amplification of the signal. The binding of a few molecules to a receptor can result in the synthesis of a large number of effector molecules because at each step of the cascade the signal is enzymatically amplified. 3. Heating of calf type I collagen fibers to 45c denatures the triple helices and separates the three chains from each other. Collagen that has been treated in this way does not renature to form a normal collagen triple helix. Why? Answer 3 The N-terminal and C-terminal propeptides pre-sent in newly synthesized collagen monomers as-ist in alignment of the peptides to form the triple helix. These propert ides are removed after the trimers are transported to the extracellular matrix, and thus are not available to perform the same function in denatured calf type I collagen. In addition will also inhibit the generation of a normal triple helir turation; these nappropriate disulfide bridges can be generated during rena13 ① 物质运输是一个耗能过程，请举例说明有哪些能量来源？ 答：①自由能；②ATP；③光能；④磷酸烯醇式丙酮酸；⑤动力势（协同） ②． What is the advantage of having an extracellular signal transmitted by a cascade of sequential events? Answer②:Transduction of an extracellular signal via a cascade of sequential events is advantageous because of the amplification of the signal. The binding of a few molecules to a receptor can result in the synthesis of a large number of effector molecules because at each step of the cascade the signal is enzymatically amplified. ③． Heating of calf type I collagen fibers to 450 C denatures the triple helices and separates the three chains from each other. Collagen that has been treated in this way does not renature to form a normal collagen triple helix. Why? Answer ③ The N-terminal and C-terminal propeptides pre-sent in newly synthesized collagen monomers as-ist in alignment of the peptides to form the triple helix. These propeptides are removed after the trimers are transported to the extracellular matrix, and thus are not available to perform the same function in denatured calf type I collagen. In addition, inappropriate disulfide bridges can be generated during renaturation; these will also inhibit the generation of a normal triple helix