Complete the sentences below with the words and phrases from the box. Translate the sentences.

1) ________________ is a process of getting older.

2) ________________ is a member of your family who lived a long time ago. (syn. forerunner)

3) ______________ is the length of time that a person or animal is expected to live.

4) To calculate the ____________ amount we add together several quantities and divide this by the total number of quantities.

5) _______________ is a mistake in something, which prevents it from working properly. (syn. defect)

6) If a molecule _____________, it divides and produces exact copies of itself.

7) To _______________ means to kill yourself deliberately.

8) ______________ is a process of making something work much better or look and feel younger and stronger.

9) To ____________ means to look after something, to keep in good condition by checking and repairing it regularly.

10) ____________ means aging and showing the effects of getting older.

Reading (1)

WHY CAN’T WE LIVE FOREVER?

It is often said that our ancestors had an easier relationship with death, because they saw it much more often. Just 100 years ago life expectancy was shorter by around 25 years in the West. Over the course of the past century sanitation and medical care dramatically reduced death rates in the early and middle years of life. Life expectancy is still increasing worldwide. Scientists are sure that aging isn’t fixed, that average life spans haven’t reached a limit. But what does science know about the aging process?

Many scientists believe that aging is caused by the gradual build-up of a huge number of tiny faults (in DNA, proteins and so on). This degenerative build-up means that the length of our lives is regulated by the balance between how fast new damage strikes our cells and how efficiently this damage will be corrected. The body’s mechanisms to maintain and repair our cells are wonderfully effective - that’s why we live as long as we do - but they are not perfect. Some of the damage passes unrepaired and accumulates as the days, months and years pass by. We age because our bodies keep making mistakes.

Nevertheless, in the 1980s certain genes were discovered by Tom Johnson and Michael Klass, who found that these genes can influence how long we live. Mutation of a gene which was named age-1 produced a 40% increase in average life span of nematode worms. Since then numerous other genes have been found which are capable of increasing life span of other animals, from fruit flies to mice.

The genes that extend life span mostly alter an organism’s metabolism, the way it uses energy for bodily functions that carry out cellular maintenance and repair. It seems that lengthening life span requires changing exactly those processes we know protect the body against build-up of damage.

New ways of slowing aging will come from learning how to manipulate damaged cells. Such sells often commit suicide, a process called apoptosis. Or they may begin to replicate uncontrollably and become cancerous or enter a senescent state in which they function but do not replicate. In theory, rescuing damaged cells from apoptosis or from senescence and inducing their rejuvenation could protect organs from the unwanted effects of injured cells. These possibilities are being tested now and investigators hope they will lead to new drug treatments.

1. Complete the phrases with the words from the following list:

medical, bodily, commit, life, damaged, deaths, cellular

1…span; 2 to…suicide; 3…cells; 4 …maintenance; 5…functions; 6…rates; 7…care.

Date: 2015-12-11; view: 1211