问题 问答题 简答题

溶酶体的生理功能主要有哪些?

答案

参考答案:

1)溶酶体的消化、营养和防御作用:溶酶体通过降解内、外源性物质并将消化产物供细胞使用。

2)在器官发育过程中起作用:在个体发育过程中器官、组织的改造形成,常常是通过组织细胞的破坏和新生实现的,在此过程中溶酶体起着重要作用。

3)溶酶体酶在细胞外的消化作用:有时溶酶体酶释放到细胞外去发挥作用。例如精子的顶体在受精时会释放出溶酶体酶消化卵细胞的外膜滤泡细胞。

4)参与激素的合成和分泌调节。

单项选择题

In the 1960s, medical researchers Thomas Holmes and Richard Rahe developed a checklist of stressful events. They appreciated the tricky point that any major change can be stressful. Negative events like "serious illness of a family member" were high on the list, but so were some positive life-changing events, like marriage. When you take the Holmes-Rahe test you must remember that the score does not reflect how you deal with stress—it only shows how much you have to deal with. And we now know that the way you handle these events dramatically affects your chances of staying healthy.

By the early 1970s, hundreds of similar studies had followed Holmes and Rahe. And millions of Americans who work and live under stress worried over the reports. Somehow, the research got boiled down to a memorable message. Women’s magazines ran headlines like "Stress causes illness. " If you want to stay physically and mentally healthy, the articles said, avoid stressful events.

But such simplistic advice is impossible to follow. Even if stressful events are dangerous, many—like the death of a loved one—are impossible to avoid. Moreover, any warning to avoid all stressful events is a prescription (处方)for staying away from opportunities as well as trouble. Since any change can be stressful, a person who wanted to be completely free of stress would never marry, have a child, take a new job or move.

The notion that all stress makes you sick also ignores a lot of what we know about people. It assumes we’re all vulnerable (脆弱的) and passive in the face of adversity (逆境). But what about human initiative and creativity Many come through periods of stress with more physical and mental vigor than they had before. We also know that a long time without change or challenge can lead to boredom, and physical and mental strain.

Why is "such simplistic advice" ( Line 1, Para. 3) impossible to follow().

A. No one can stay on the same job for long

B. No prescription is effective in relieving stress

C. People have to get married someday

D. You could be missing opportunities as well

单项选择题