The Secret Of Staying Young Reading Answers: IELTS Reading Practice Test

"The Secret of Staying Young" explores the science behind ageing, drawing on studies of long-lived animals, including naked mole rats and certain bat species, to understand what controls the rate at which cells age. 

The passage examines the role of telomeres, cell division limits, DNA damage, and gene activity in determining lifespan. 

It is taken from Cambridge IELTS 11, Academic Test 3, Passage 2.

Paragraph A 

Living things age and die. That much is obvious. But why ageing happens and why some creatures age so much more slowly than others is one of the great mysteries of biology. Researchers have long known that body size is not a reliable guide to lifespan. Elephants live longer than mice, it is true, but bats, which are small mammals, can live for thirty years or more, far longer than much larger animals. The relationship between size and longevity is clearly more complicated than it first appears.

Paragraph B 

One of the most significant advances in understanding ageing came with the discovery that most cells in the body can only divide a limited number of times. This limit, known as the Hayflick limit, after the biologist Leonard Hayflick who identified it in the 1960s, means that cells accumulate damage over time and eventually stop dividing altogether. When enough cells in a tissue reach this state, the tissue begins to deteriorate, and ageing becomes visible. The rate at which cells approach their division limit is therefore central to how quickly an organism ages. Faster cell division means faster ageing.

Paragraph C 

The mechanism behind the Hayflick limit lies in structures called telomeres, protective caps on the ends of chromosomes. Each time a cell divides, its telomeres shorten slightly. When they become too short, the cell can no longer divide safely, and it enters a state of permanent inactivity or destroys itself. Telomeres are, therefore, a kind of biological clock. The rate at which they shorten is influenced by many factors, including the level of an enzyme called telomerase and the degree of DNA damage the cell accumulates during its lifetime.

Paragraph D 

Some animals appear to have evolved mechanisms that slow telomere shortening dramatically. Naked mole rats small, hairless rodents that live underground in East Africa, are a striking example. They live for up to thirty years, which is exceptionally long for an animal of their size. Research has shown that naked mole rats have unusually stable telomeres and very low rates of DNA damage compared with mice of a similar size that live for only two or three years. Their cells also appear to be far more resistant to the kinds of stress that normally accelerate ageing in other mammals.

Paragraph E 

There is, however, a complication. The same cellular mechanisms that allow long-lived animals to resist ageing also appear to create a vulnerability to cancer. Cells that do not age quickly are cells whose division is not tightly controlled, and uncontrolled cell division is the defining feature of cancer. Naked mole rats have developed an unusual solution to this problem: their cells produce a sugar called hyaluronan in unusually high concentrations, which appears to prevent tumour formation. This means they are not only long-lived but also remarkably cancer-resistant, a combination that makes them of particular interest to medical researchers.

Paragraph F 

Understanding which genes control the rate of ageing has become a major focus of biological research. Scientists have identified several genes in organisms ranging from yeast to roundworms to mice that, when altered, extend lifespan significantly. In some cases, a single gene change has doubled the lifespan of an experimental animal. These findings suggest that ageing is not simply an inevitable consequence of living but a biological process that is subject to genetic control. The possibility that similar genes might operate in humans has made this one of the most actively funded areas of life-science research.

Paragraph G 

For humans, the picture is more complex. Genes clearly play a role in determining how long a person lives. Studies of twins suggest that roughly a quarter of the variation in human lifespan is attributable to genetic factors. But the majority of the variation comes from non-genetic sources. Diet, exercise, smoking, and other aspects of lifestyle account for a far larger share of differences in human longevity than genes do. This means that, for most people, the most reliable path to a longer life is not waiting for a genetic breakthrough but making better choices about how they live.

Questions 1–6: True/False/Not Given

Do the following statements agree with the information given in the passage? 

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this in the passage

1. Body size is a reliable indicator of how long an animal will live.

2. Leonard Hayflick discovered that cells can only divide a fixed number of times.

3. Telomerase levels are higher in bats than in most other mammals.

4. Naked mole rats have lower rates of DNA damage than mice of a similar size.

5. The high concentration of hyaluronan in naked mole rats causes them to age more quickly.

6. Gene-based anti-ageing treatments for humans are currently available in clinical settings.

Questions 7–13: Sentence Completion

Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer.

7. The rate at which cells approach their division limit determines how quickly an organism ages, and faster __________ means faster ageing.

8. Protective caps on the ends of chromosomes are called __________.

9. The rate at which telomeres shorten is influenced by the level of telomerase and the degree of __________ the cell accumulates.

10. The long lifespan of __________ has made them of particular interest to researchers studying ageing.

11. The same cellular mechanisms that slow ageing in long-lived animals also create a vulnerability to __________.

12. Scientists have found that altering a small number of __________ can significantly extend the lifespan of experimental animals.

13. For most people, differences in human longevity are more closely linked to __________ than to genetic factors.