有关细菌内毒素的特点下列错误的是
A．主要由革兰阴性杆菌产生
B．化学成分主要是脂多糖
C．对人体组织有选择性毒性作用
D．可单独激活补体旁路途径
E．可使鲎血液变形细胞溶解物凝固
参考答案：C
解析： 内毒素是G-细菌细胞壁中的结构组分在菌细胞破裂后释放出来的毒性脂多糖，毒性相对较弱且无选择性，可单独激活补体旁路途径，可使鲎血液变形细胞溶解物凝固。
| 短文填空。阅读下面短文，请根据短文内容从方框中所给的15个词中选用10个词并用其正确形式填空。 每个词只能选用一次。 | |
habits. Here is some 2_____ on what to do if you want to be healthy. Early to bed and early to 3_____ makes a man healthy and wise. This is an old English 4_____. Is this true? Perhaps it is. The body must have enough sleep. If you do not go to bed early, you cannot have enough sleep. Then you cannot think or do your work 5_____. Some people go to bed late at night and get up late in the morning. This is not good 6_____ them. We must sleep at night when it is dark. The dark helps us to sleep well. When the 7_____ comes, we must gel up. This is the time for exercise. Exercise keeps the body 8_____. Exercise helps the blood to move around inside the body. Blood 9_____ food to all parts of our bodies. The brains in our heads also need blood. We think with our brains. If we take exercise and keep our bodies healthy, we 10_____ think well. |