Spider silk Reading Exercise

A

Researchers have successfully replicated the silk-producing genes of the Golden Orb Weaver spider and are employing them to develop a synthetic material that they believe will serve as a prototype for advanced biologically-derived materials. The new material, biosilk, which has recently been spun by scientists at DuPont, boasts an extensive array of potential applications in construction and manufacturing.

B

The allure of spider-spun silk stems from its exceptional strength and tremendous elasticity, characteristics that synthetic fibers have thus far been unable to replicate. Pound for pound, spider silk surpasses steel in strength, and experts estimate that a single strand with a diameter of approximately 10 meters could arrest a jumbo jet in flight. Its lightweight nature adds to its appeal. Military scientists are already exploring its potential for lightweight, bulletproof vests and parachutes.

C

For some time now, biochemists have endeavored to synthesize the drag-line silk of the Golden Orb Weaver spider. This silk, which forms the radial arms of its web, surpasses other components of the web in strength, leading some biochemists to speculate that a synthetic version could prove as transformative as nylon, a material that has been pivotal for the past 50 years since the pioneering work of Wallace Carothers and his team marked the advent of polymer age.

D

In order to replicate the material, scientists, including Randolph Lewis from the University of Wyoming, initially examined the spider's silk-producing gland. 'We extracted the glands responsible for silk production and analyzed the protein coding that forms the web. Subsequently, we searched for clones containing the appropriate DNA,' he explains.

E

At DuPont, researchers have utilized both yeast and bacteria as hosts to cultivate the raw material, which has been spun into fibers. Robert Dorsch, DuPont’s director of biochemical development, explains that protein globules, similar in size to marbles in an egg, are harvested and processed. 'We rupture the bacteria, separate the protein globules, and utilize them as the raw material. With yeast, we engineer the genetic system so that the protein is secreted outside the yeast for better accessibility,' he says.

F

'Both bacteria and yeast produce the same protein used by spiders in the draglines of their webs. Spiders mix the protein into a water-based solution and spin it into a solid fiber in one continuous process. Since we're not as sophisticated as spiders and aren't using such advanced organisms, we've substituted with synthetic methods. We dissolve the protein in chemical solvents, which are then spun through small holes to form solid fibers.'

G

Researchers at DuPont envision numerous potential applications for the new biosilk material. They believe that earthquake-resistant suspension bridges supported by cables made of synthetic spider silk fibers could become a reality. Other applications include stronger ropes, safer seat belts, shoe soles that last longer, and durable new clothing. Biochemists like Lewis see the potential applications of biosilk as nearly limitless. 'It’s incredibly strong and retains elasticity—there are no synthetic materials that can replicate both properties. It’s also a biological material, offering advantages over petrochemicals,' he states.

H

At DuPont's laboratories, Dorsch is enthusiastic about the potential of new super-strong materials but cautions that they are still many years away. 'We're in the early stages, but theoretical projections indicate that we'll ultimately achieve a very strong, resilient material with excellent shock-absorbing capabilities—stronger and tougher than conventional man-made materials available to us,' he remarks.

I

Material scientists have not only focused on spiders but also shown interest in the natural adhesive secreted by the sea mussel. This protein adhesive allows the mussel to attach itself to rocks. Due to the difficulty and cost of extracting the protein from mussels, researchers have developed a synthetic gene for use in surrogate bacteria.

Questions 1-5

Reading Passage 1 has nine paragraphs, A-I

In which paragraph is the following information found?

Write the correct letter, A-I, in boxes 1-5 on your answer sheet.

1 a comparison of the ways two materials are used to replace silk-producing glands

2 predictions regarding the availability of the synthetic silk

3 ongoing research into other synthetic materials

4 the research into the part of the spider that manufactures silk

5 the possible application of the silk in civil engineering

Questions 6-10

Fill in the flow chart below.

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

Write your answers in boxes 6-10 on your answer sheet.

Synthetic gene grown in 6…  or 7…

↓

globules of 8… .

↓

dissolved in 9…

↓

passed through 10…

↓

to produce a solid fibre

Questions 11-13

Are the following statements supported by the information in the Reading Passage?

In boxes 11-13 on your answer sheet, write

TRUE           if the statement is true

FALSE          if the statement is false

NOT GIVEN    if the information is not given in the passage

11  Biosilk has already replaced nylon in parachute manufacture.

12 The spider produces silk of varying strengths.

13 Lewis and Dorsch co-operated in the synthetic production of silk.

Answers:

1. E (Đoạn E, “At DuPont, researchers have used both yeast and bacteria as hosts to grow the raw material, which they have spun into fibres.”)

2. H (Đoạn H, “Dorsch is excited by the prospect of new super-strong materials but he warns they are many years away.”)

3. I (Đoạn I, “The spider is not the only creature that has aroused the interest of material scientists.”)

4. D (Đoạn D, “To recreate the material, scientists, including Randolph Lewis at the University of Wyoming, first examined the silk-producing gland of the spider.”)

5. G (Đoạn G, “Researchers at DuPont say they envisage many possible uses for a new biosilk material.”)

6. yeast (Đoạn E, “At DuPont, researchers have used both yeast and bacteria as hosts to grow the raw material, which they have spun into fibres.”)

7. bacteria (Đoạn E, “At DuPont, researchers have used both yeast and bacteria as hosts to grow the raw material, which they have spun into fibres.”)

8. protein (Đoạn E, “Robert Dorsch, DuPont’s director of biochemical development, says the globules of protein, comparable with marbles in an egg, are harvested and processed.”)

9. chemical (Đoạn F, “…we substituted man-made approaches and dissolved the protein in chemical solvents”)

10. holes (Đoạn F, “…which are then spun to push the material through small holes to form the solid fibre.”)

11. FALSE (Đoạn B, “Army scientists are already looking at the possibilities of using it for lightweight, bulletproof vests and parachutes.”)

12. TRUE (Đoạn G, “They say that earthquake-resistant suspension bridges hung from cables of synthetic spider silk fibres may become a reality. Stronger ropes, safer seat belts, shoe soles that do not wear out so quickly and tough new clothing are among the other applications.”)