中考生物（人教版）专项训练五（解析版）
题型：选择题※难度：较易
<div><div><p>【题目】通过呼吸运动，肺实现了与外界环境的气体交换，下面关于平静呼吸的表示，哪项是正确的</p><p>A. 胸廓扩大→肺扩大→肺内气压>大气压→气体入肺</p><p>B. 胸廓缩小→肺回缩→肺内气压<大气压→气体出肺</p><p>C. 胸廓扩大→肺扩大→肺内气压<大气压→气体入肺</p><p>D. 胸廓缩小→肺回缩→肺内气压>大气压→气体入肺</p><p> </p></div></div>
<div><p>【答案】C</p><p>【解析】参加呼吸运动的肌肉主要有膈肌、肋间肌等呼吸肌。平静呼吸吸气时：肋间外肌、膈肌收缩→肋骨向上向外移动、膈肌顶部下降→胸廓扩大→肺扩张→肺内气压＜外界大气压→外界气体进入肺；呼气：肋间外肌、膈肌舒张→肋骨下降，膈肌顶部回升→胸腔容积缩小→肺回缩→肺内气压＞外界大气压→肺内气体排出。</p></div>
题型：综合题
※难度：容易
<div><div><p>【题目】下图中甲、乙、丙三条曲线分别表示食物中三种营养物质在消化道中的变化情况。据图回答；</p><p><img src="https://picture.zhihuicn.com/2017/12/30/23/3de0331d/SYS201712302345332134739499_ST/SYS201712302345332134739499_ST.001.png" width="149" height="105" alt="" style="-aw-left-pos:0pt; -aw-rel-hpos:column; -aw-rel-vpos:paragraph; -aw-top-pos:0pt; -aw-wrap-type:inline" /></p><p>（1）图中曲线乙表示________的消化。</p><p>（2）从图中看，淀粉最终在________中彻底消化分解成葡萄糖。</p><p>下面是某生物兴趣小组的同学在探究“口腔对淀粉的消化作用”课题时设计的实验方案，如下表。分析完成下列问题：</p><div><table cellspacing="0" cellpadding="0" style="width:431.55pt; margin-right:auto; margin-left:auto; border:0.75pt solid #000000; border-collapse:collapse"><tr><td style="width:75.1pt; border-right-style:solid; border-right-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>试管编号</p></td><td style="width:53.95pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>1</p></td><td style="width:53.95pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2</p></td><td style="width:53.95pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>3</p></td><td style="width:53.95pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>4</p></td><td style="width:75.1pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>5</p></td></tr><tr style="height:31.7pt"><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>馒头碎屑或块</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>适量碎屑</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>适量碎屑</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>适量馒头块</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>适量碎屑</p></td><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>适量碎屑</p></td></tr><tr style="height:43.85pt"><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>唾液有无</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2 mL唾液</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2 mL清水</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2 mL唾液</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2 mL唾液</p></td><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>2 mL唾液</p></td></tr><tr><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>是否搅拌</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>搅拌</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>搅拌</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>不搅拌</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>搅拌</p></td><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>搅拌</p></td></tr><tr><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>温度</p></td><td colspan="3" style="width:183.45pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>37℃</p></td><td style="width:53.95pt; border-style:solid; border-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>0℃</p></td><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; border-bottom-style:solid; border-bottom-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>100℃</p></td></tr><tr><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>加入碘液</p></td><td style="width:53.95pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>＋</p></td><td style="width:53.95pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>＋</p></td><td style="width:53.95pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>＋</p></td><td style="width:53.95pt; border-top-style:solid; border-top-width:0.75pt; border-right-style:solid; border-right-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>＋</p></td><td style="width:75.1pt; border-top-style:solid; border-top-width:0.75pt; border-left-style:solid; border-left-width:0.75pt; padding-right:5.03pt; padding-left:5.03pt; vertical-align:middle"><p>＋</p></td></tr></table></div><p>（3）要探究牙齿的咀嚼、舌的搅拌对馒头的消化作用，应选用________号试管进行对照实验。</p><p>（4）如果选用1、4、5号试管进行实验，其探究的问题是：_____________________？</p><p>（5）实验5分钟后将1号试管取出，滴加碘液摇匀，如果实验现象未达到预期效果，呈现浅蓝色，可能的原因是________________（写出一种即可）。</p><p> </p></div></div>
<div><p>【答案】（1）蛋白质；</p><p>（2）小肠；</p><p>（3）1和3；</p><p>（4）温度对唾液淀粉酶消化淀粉是否有影响？</p><p>（5）实验时间不足，淀粉没有充分分解成麦芽糖，剩余淀粉遇碘变蓝色．（或者唾液的量偏少或搅拌不充分或馒头碎屑偏多）。</p><p>【解析】</p><p>试题分析：（1）蛋白质的消化开始于胃，在小肠内被彻底消化，分析图可知，乙曲线表示蛋白质的消化过程。</p><p>（2）从图中可以看出，淀粉在小肠内被最终消化；小肠是消化食物和吸收营养物质的主要场所，这是因为长约5～6m，小肠内具有肠液、胰液和胆汁等多种消化液；小肠内壁有环形皱襞，皱襞上有小肠绒毛，增大了消化和吸收的面积；小肠绒毛内有毛细血管和毛细淋巴管，都是由一层上皮细胞构成的，有利于营养物质的吸收。</p><p>（3）1号试管与3号试管形成了以牙齿的咀嚼和舌的搅拌为变量的对照实验，该组实验的结果表明牙齿的咀嚼和舌的搅拌有助于淀粉的消化。</p><p>（4）1、4、5号试管是以温度为变量形成的对照实验，目的是探究温度对唾液中唾液淀粉酶发挥作用的影响，因此提出的问题应该是：温度对唾液淀粉酶消化淀粉是否有影响？</p><p>（5）1号试管的实验现象未达到预期效果、呈现浅蓝色，说明试管内的淀粉没有被彻底分解，造成这种情况的原因是多方面的：水浴时间不够长，淀粉没有被完全消化；搅拌不充分，淀粉与唾液淀粉酶的接触面积小也可能导致淀粉没有被彻底分解；唾液的量太少也可能导致淀粉的消化不充分。</p></div>
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