[caption id="attachment_506" align="alignleft" width="290" caption="By Stew Dean"][/caption]

DNA is one of the most perplexing and mystifying substances known to man. All of the code for every part of a living thing is contained in a seemingly simple strand of chemicals. Upon closer look, however, DNA is not what it seems. Consider this, 6 feet of DNA is coiled into each of your 1 trillion cells. You have enough DNA in your body to wrap around the earth multiple times. Honors Biology has spent the last week working through the unraveling of the secrets of DNA. Thursday will conclude our studies of the topic. Our review of last week (2/20-2/24) comes to us from La'mia Baldwin and Ari Holmes.

La'mia writes:

During the week of February 20-24 in Biology we learned many things. We found out what Griffith, Avery, Hershey and Chase did. Griffith discovered that there was a molecule that is capable of transferring information. Avery discovered that DNA stores and transmits genetic information. Hershey and Chase used viruses to prove that DNA was the material that transmits genetic information. We learned that there are 4 different bases in DNA (A, T, C, and G) and A matches with T and C matches with G. We learned about the structure of DNA and Chargaff’s rule. We also learned about Watson and Cricks models. We learned the steps to replication: 1) Helicase unwinds DNA and breaks the bonds between bases, 2) DNA polymerase travels down the template strand and add new bases, 3) A different DNA polymerase “proofreads” the work of the 1st DNA polymerase, 4) The process continues until the one old strand is separated into a new strand (semi-conservative replication). We learned the 3 types of RNA which was MRNA, TRNA, and RRNA. We also learned the differences between DNA and RNA; RNA has one strand, uses U instead of T, and RNA uses Ribose instead of deoxyribose. The process of transcription: 1) RNA polymerase binds to a promoter, 2)RNA polymerase unwinds and unzips the strand of DNA, 3) RNA polymerase uses one side of the DNA as a template to create a strand of MRNA, 4) Once the genes been transcribed into MRNA, the MRNA undergoes processing and leaving the nucleus. We move on to learn about Translation and in translation proteins are polymers and monomers are amino acids. We learn the translation process: 1) MRNA attaches to a Ribosome, 2) Ribosome’s read the MRNA 1 codon a time, 3) When the ribosome hits a codon a TRNA brings the correct amino acid, 4)The amino acid is added to the growing polypeptide chain, 5) The TRNA leaves and go’s to another amino acid, 6) The next TRNA brings its amino acid add to the chain, the process continues until the ribosome’s reaches a stop codon.

Ari Concludes:

This week in Honors Biology, we learned about DNA (Deoxyribonucleic acid) and RNA (ribonucleic acid). For those who do not know anything about DNA, I'm going to tell you the basic key points you should know. First things first, DNA is the reason why you may look like your parents or have certain traits from either parent. The structure of DNA; DNA has 4 nitrogen bases. Adenine and Guanine (Purines) and Cytosine and Thymine (pyrimidines). DNA also is a polymer and its monomer is nucleotides.

With these four nitrogenous bases remember that in DNA Adenine will only go with Thymine and Guanine will only match with cytosine. As far as RNA goes, I'm going to do the same thing and hit a few bullet points. The main function(s) of RNA is to carry the instructions for Amino Acids. One of the RNAs jobs is protein synthesis. There are three types of RNA. mRNA carries copies of the instructions for assembling amino acids into proteins from DNA to the rest of the cell. rRNA makes ribosomes. tRNA transfers each amino acid to help assemble proteins. That's all about RNA.



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