IV. Do you know the meaning of the given words? If not, find the explanation of these notions.

Ribosome, protein, DNA

Are you familiar with the name of Alexander Zettl?

How can this information help you understand the text?

V. Make up sentences paying attention to the meaning of the word in ex.II:

1. are/methods/widely/these/advanced/used

2. this/touch/structure/don’t/delicate

3. working/toward/we/deliberately/ manufacturing/molecular/aren’t

4. machines/not/be/in/should/immersed/water/these

5. on/immobilized/motors/are/molecular/the/surface

6. manufacturing/the/molecular/involves/use/machines/of/tiny

7. to/the/be/tends/information/imprecise

8. without/do/you/external/can/manipulation/it

9. the/turn/motors/propellers/the

10. structure/nanoscale/is/a/imposing/it.

VI. A) Choose the passive or active form in brackets Decide what form in brackets is a correct one

Robots building robots sounds convenient--but how do you build the first one, especially when they're too small to see?

Manufacturing at the nanoscale - imposing structure on nanoscale objects -can (do / be done) in several ways. One is to build all the information needed into the ingredients, so that they form the (desiring / desired) structure without external manipulation. This is called self-assembly, and it's a promising approach, but difficult because it's indirect. Another way to make nanoscale structures is to use relatively large and very delicate machinery, such as (being focused / focused) ion beams and (scanned / scanning) probe microscopes. This tends to be expensive, slow, and imprecise. The third way to manufacture at the nanoscale, in theory, is to use very small machinery--but that raises the question of where the machinery comes from.

Molecular manufacturing (is involved / involves) the use of tiny molecular machines which are capable of building more molecular machines. Such things exist in nature; in fact, that's what the molecular machinery of cells does--ribosomes (are built / build) protein using instructions from DNA. However, the natural molecular machines are difficult (to engineer / to be engineered): it is hard to make a cell build what you want, especially if you want something other than protein. So the goal of molecular manufacturing is to use artificial engineered machines (to build / to be built) more machines as well as other products. And for highest performance, these machines should be "dry" - not immersed in water -which makes them rather different from biological designs.

B) Decide what form in brackets is a correct one

Few molecular machines (demonstrated / have been demonstrated) so far, and most of those (are based / base) on biology. For example, molecular motors from cells (have been immobilized / immobilized) on a surface and tiny pieces of metal (attached / have been attached) to them. When the right chemicals (add / are added), the motors turn the "propeller." This is great for research, but it's a far cry from the robot-building-robot goal of mature molecular manufacturing.

The broader field of nanotechnology has advanced sufficiently that researchers, even when they are not working deliberately toward molecular manufacturing, frequently do work that is relevant to it. For example, Alexander Zettl has built a motor which (doesn’t base / is not based) on biomaterials at all, (is not immersed / doesn’t immerse) in water, and (doesn’t power / is not powered) chemically. It (is constructed / constructs) by building a bearing out of nested carbon nanotubes, attaching a piece of metal to it, and then using electric fields to move the metal. It is a very mechanical structure, susceptible to engineering and analysis and improvement. But it was hard to build, because it (required / was required) large machines working at their limits of precision.