Bio Study Sheet May Four

Bio Study Sheet 5/4 What is the purpose of DNA? – – – – –

Complete set of information coding for traits- human genome (library) Every cell has a full copy but they are specialized Every cell has 23 chromosomes- each chromosome contains the instructions for a particular set of traits (chromosome is a book) On chromosomes which are made up of DNA there are sections coding for a particular trait, or in other words a gene (gene is a chapter) ATCG- all the traits in the body are determined by sequences of A,T,C,G Textbook Stuff

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Changing the Living World In hybridization two different organisms are crossed to bring out the best in each Humans use selective breeding to pass on desired traits to the next generation In inbreeding desired traits that are already existent in a generation are kept alive by mating them with others who have these traits Mutations are inheritable traits within DNA and they help keep variation Bacteria are easily mutated b/c they are small and can be mutated in large numbers under little radiation, this helps create useful bacteria Some drugs stop separation in meiosis and can produce polyploids which means they have many sets of chromosomes, b/c plants are more tolerant of having extra chromosomes they can be produced and are stronger than diploid relatives Manipulating DNA

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Scientists want to analyze the base pairs of DNA and make unlimited copies of it In genetic engineering try to make changes to part of DNA Cells are opened and DNA and cell parts separated Too large to be analyzed so use restriction enzymes (cuts the ends of certain DNA frags) Gel electrophoresis makes go down smallest goes fastest Can be used to locate one gene in a million In cutting and pasting synthetic sequences can be attached to normal ones using an enzyme, same enzyme allows take gene from one org and put it into DNA from another, recombinant DNA To copy DNA take strand and split in half using heat, then add in complementary pairs to two separate strands and you have two full, separate the new ones and add in another complementary pair and so on

Cell Transformation

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In transformation cell takes in DNA from outside the cell and this DNA becomes part of the cell’s DNA Takes plasmid and edits b/c it will always replicate in a new cell Also has genetic marker Animal cells can be transformed by replacing target gene with recombinant DNA In genetic engineering transgenic organisms

Other Junk (Protein Synthesis) Prokaryotes have less DNA and it is carried around in the cytoplasm Nucleosomes store huge amounts of DNA into a tiny space and they form coils which form supercoils which are on chromosomes Since strands are made from complementary base pairs one strand can make another In DNA replication the two strands separate, make complementary pairs, come together, and the new ones that were created come together DNA polymerase makes the two separate strands make complementary base pairs and it checks to make sure the complementary strand is correct RNA Ribose, single stranded and uracil instead of thymine Disposable copy of a single gene Messenger RNA carries instructions for creating certain proteins Ribosomal RNA is a part of a ribosome tRNA transfers each type of amino acid to the ribosome as the mRNA commands IN TRANSCRIPTION a part of a nucleotide of DNA is copied into complementary pairs for RNA, RNA polymerase does this by connecting to one strand of DNA and making a complimentary copy There are promoters on DNA which tells RNA polymerase where to connect to build the correct RNA molecule The entire copied sequence is too large so introns are cut out and only exons are left, they then fuse together to create the final mRNA A codon is three consecutive nucleotides (base pair) that specifies an amino acid to be created, remember reads three at a time IN TRANSLATION mRNA is translated into a protein

1) First mRNA must be transcribed from DNA and released into the cytoplasm 2) Translation starts when mRNA connects to a ribosome. As each codon moves through the ribosome the amino acid it coded for is added to the polypeptide chain. The ribosome can’t identify what is being coded for so tRNA has an amino acid tied to one end and a region of three unpaired bases at another. The bases on the tRNA are complementary to the ones on the mRNA codon. The bases on tRNA are the anticodon. What would happen is an mRNA codon would be held in the ribosome till the complementary tRNA got there. Then the tRNA with

the right anticodon would release the amino acid it held into the chain. The amino acid is released b/c the ribosome breaks the bond with the tRNA molecule. It lets the molecule go after it is done with it. 3) This continues until mRNA codes for a stop amino acid. Then the chain is done!

DNA is the master plan and RNA is the blueprint. The DNA stays safe while the RNA does its job. Genes and proteins are related b/c genes code for proteins. Mutations are changes in a DNA sequence that affects genetic information. A point mutation takes place on a single point on DNA and really just substitutes one gene for another. In a frameshit mutation a nucleotide is added so then the whole things gets messed up (Fat Cat thing).