Science 10 Project Presentation

Science 10 Project Presentation Hello everyone. I’m going o present the project I’ve done: “Fascinating Creatures: Spider and its Silk”. You can find spiders almost everywhere in the world; under the ground up to the highest mountain, deserts to your house – especially your bathroom because they need water to survive. Spiders are not insects; they are below the class of Arachnids with scorpions. A spider’s anatomy has 2 parts: cephalothorax and opisthosoma. Cephalothorax is the part which included its head and thorax, and opisthosoma, or abdomen, included its stomach and spinnerets. Most spiders are not that dangerous and in facts, they can help human to catch little tiny harmful insects like flies, mosquitoes, and etc. Spiders can walk on the walls and ceilings because they have special pads on their feet. Some of the spiders can do regeneration like a starfish, if a spider loses a leg it will grow back. That was some basic knowledge about spiders and now I’m going to introduce you about spider’s silk. Spider’s silk is a very strong fibre which can compare to a high-grade steel and it is also very ductile. The structure of a spider silk is made up of crystalline connected with amorphous linkages. A crystalline is build up by beta-sheets. Spiders use their spinnerets to produce silks; a spider has 2 to 8 spinnerets usually in pairs. Normally, spiders use their silk to make a web, climbing on the walls, flying with the wind, and form smooth walls for their hole. Now I’m going to talk a little bit about spider webs. The common types of spider webs are orb web and triangle web. The reason of why a spider would not get trapped in its web it’s because it has an oily substance covered its body. Spider webs will lose its stickiness after a time. Some of the spiders would eat

their old one to convert into new spider silk. Here’s something interesting: drugs and medicine can affect the beaviour of a spider. Scientists from United States National Aeronautics did an experiment of how a spider make its web after took some medicine. Here are the results……I also brought a movie about spiders on drugs… Okay, the last part I’m going to talk about is artificial spider silk. Before biotechnology invented, fishermen lived in in-do ocean already use spider webs to catch small fishes. Spider silk is a very useful material but it is too hard to get a huge amount from spiders and it is also too expensive. In 2000, a Canada biotechnology company, Nexia, tried to producing artificial spider silk protein in transgenic goat. Those goats carried the gene for spider silk in its milk. However, they found out that it is too hard to spin the proteins into a fibre similar to natural spider silk because they couldn’t make an environment like the spinnerets does. The spinnerets in spider’s body create a good environment of protein concentration, pH, and pressure to change the protein into the structure of a normal spider silk. Another researcher is Randolph Lewis, a molecular biologist at the University of Wyomin. His team cloned spider silk genes and implanted them in the bacteria. Lewis said: "I think soon we'll be able to make a close analog of spider silk. Will it be identical to spider silk? Probably not, but it may still be an excellent fibre." The conclusion was: people could make some similar fibre like spider silk, but we couldn’t make the same fibre as the spider does; that’s the secret of the nature. That’s the end of my presentation.