Are You suprised



Biology Gr10DNA & Protein Synthesis Name:____________________Class:____________________Date:____________________Read the passage below. Then answer the questions that follow.Two Monkeys See a More Colorful World Vocabulary Highlight the main vocabulary terms.Write these terms in your notebookFor a pair of squirrel monkeys named Sam and Dalton, the world recently got more colorful. Male squirrel monkeys are normally red-green colorblind, which means they have trouble seeing those colors. But now, thanks to an experiment by scientists at the University of Seattle, Sam and Dalton see things differently—they seem to be able to see red and green.Animals (including people) are able to see different colors of light thanks to proteins in the eye. Proteins are important building blocks of cells, and different kinds of proteins serve specific purposes in a living organism. When an important protein is absent or disabled, the animal cannot function properly. Male squirrel monkeys normally lack the proteins that detect red and green light, which means they can’t tell red and green from other colors. The monkeys can see blue and yellow.A colorblind male squirrel monkey named Dalton is pictured here taking a color vision test. Neitz Laboratory, University of WashingtonJay Neitz is the scientist at the University of Washington who led the research to give the monkeys more colorful vision. Neitz and his team were able to add genes that make proteins for detecting red light in the monkey’s eyes. A gene is like a recipe for building a protein, and different genes direct the body how to build different proteins. Almost every cell of a living organism contains DNA, or deoxyribonucleic acid, which is the set of instructions for how to make that organism function. These instructions include all the genes, which are segments of DNA encoding for a specific character. Looking closer What are the two main steps in gene expression? ____________________________Gene expression is the process by which genes results in the production of proteins. It consists of two main steps: transcription and translation. During transcription, information in a particular region of DNA is copied into mRNA “messenger RNA”. RNA or ribonucleic acid is a nucleic acid, that unlike DNA , is single stranded, contains ribose sugar instead of deoxyribose, and has the nitrogen base uracil instead of thymine. After transcription, mRNA moves from the cell nucleus to ribosomes in the cytoplasm to be translated into proteins. Each mRNA triplet codon either matches one amino acid or acts as a signal to stop or start translation. The result of translation is a complete polypeptide or protein. Proteins, in turn, produce almost all traits of an organism. Reading CheckDefine what is gene therapy ?____________________________________________________________A gene is also responsible for building the protein that enables the animal to see the color red. Neitz and his team found male squirrel monkeys that don’t have this gene—so for their experiment, they tried to give the gene to the monkeys. They injected the monkeys with a virus that contained the gene. Over the next few weeks, the monkeys began to make the red-detecting protein. After about 20 weeks of this gene therapy, the monkeys were making enough of the protein to be able to tell red from green.To test the monkeys’ eyesight, Neitz and his team showed them a grid of dots, some of them colored, some of them gray. If the monkeys pressed the colored dots, they received a treat—grape juice. Before the gene therapy, the monkeys could easily pick out blue or yellow dots, but they had a hard time telling red or green dots from gray dots or from each other. After receiving the gene injections, Sam and Dalton were able to pick out all of the colors (and drink lots of grape juice). Critical thinking Why do you think the experiment of Sam and Dalton is not reliable to prove that genetic therapy can help colorblind people?______________________________________________________________________Bevil Conway, a neuroscientist at Wellesley College in Massachusetts, says the experiment shows that seeing in full color only requires the addition of a gene for detecting certain colors of light. Before the experiment, scientists were not sure whether the monkey’s brains would know how to handle new colors—but the monkeys seemed to be able to see and understand the new colors right away. “Somehow the brains of these monkeys are already wired to decode these color signals,” Conway says. Neitz’s experiment is good for Sam and Dalton—but what about the rest of the world? They say it’s too early to know if genetic therapy could ever be used to help colorblind people see colors, or to help blind people see. Plus, it may be true that Sam and Dalton aren’t seeing red and green as we know them—they may just be seeing other shades of yellow and blue. Nonetheless, the idea of giving color vision to a couple of monkeys is capturing the attention of researchers who study vision. “The achievement is technically amazing and conceptually very cool,” says Melissa Saenz, a scientist at Caltech in Pasadena, Calif. SKILL: READING EFFECTIVELYRead each question, and write your answer in the space provided.Write a definition of each of the following in your own words:Gene:__________________________________________________________________________________________________________________________Gene expression: __________________________________________________________________________________________________________________________What role does mRNA play in gene expression ?__________________________________________________________________________________________________________________________Define red-green colorblindness as described in the text.__________________________________________________________________________________________________________________________Summarize the experiment conducted by Neitz and his team. ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________How did Neitz and his colleagues test the monkey’s eyesight? _______________________________________________________________________________________________________________________________________________________________________________________6. What is the difference between transcription and translation?Distinguish between DNA and RNA .________________________________________________________________________________________________________________In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.1.During transcription, the genetic information for making a protein is rewritten as a molecule ofa.messenger RNA.c.transfer RNA.b.ribosomal RNA.d.translation RNA.2.All organisms have a genetic code made ofa.two-nucleotide sequences.c.four-nucleotide sequences.b.three-nucleotide sequences.d.five-nucleotide sequences.3.In a cell, the equipment for translation is located in thea.cytoplasm.c.plasma membrane.b.nucleus.d.centrioles.4.Like DNA, RNA contains which of the following?a.phosphatec.thymineb.uracild.deoxyribose5.RNA differs from DNA because RNAa.is single-stranded. b. contains a different sugar. c.contains uracil d. All of the above6.The function of mRNA is toa.synthesize DNA.b.carry information from genes to ribosomes.c.form ribosomes. d. transfer amino acids to ribosomesMatch the words on the left with the statements on the righta three-nucleotide sequence that specifies an amino acid or “start” or “stop” signalb. putting together the amino acids that make up a proteinc.this type of RNA carries the instructions for making a protein from a gene to the site of translationd.transferring genetic information from a gene to e. a nitrogenous base in RNA mRNA1.messenger 2.codon3.transcription4.uracil5.translation ................
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