Nucleic Acids and Protein Synthesis Photo credit: Jacob Halaska/Index Stock Imagery, Inc. Copyright Pearson Prentice Hall

Two Types of Nucleic Acids: 1. DNA 2. RNA Together they have the code and capability to make all necessary proteins. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA Deoxyribonucleic Acid -our genetic code -code for making all proteins/enzymes = all our traits and cell reactions Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA is: Located: in the nucleus of all our cells. Makes up our: Chromosomes Number of chromosomes in each of our cells? 46 23 from mom 23 from dad Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Chromosomes: -46 linear segments of DNA -Super coil into “bow tie” shaped structures during cell division. Copyright Pearson Prentice Hall

Approximately 6ft/cell ~ supercoils into mere nanometers Supercoiling of DNA Approximately 6ft/cell ~ supercoils into mere nanometers Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Human Genome: - our complete set of genes that makes up a human. -22,000 genes in our genome. -99.9% of every humans genes is identical. There is only a .1% sequence variation from person to person Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Genes: segments of DNA that codes for 1 or more proteins. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Every cell in your body has an exact copy of all 46 chromosomes but……. Cells are selective on what genes are read and proteins made. Ex/ skin makes collagen pancreas makes insulin Copyright Pearson Prentice Hall

-Mapped all of our genes. -Headed by James Watson -Completed in 2003 -Headed by James Watson Copyright Pearson Prentice Hall

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Copyright Pearson Prentice Hall Structure of DNA: 1. is a nucleic acid 2. made up of nucleotides Each nucleotide is made up of: 1. Pentose sugar (5 sided) “deoxyribose” 2. Phosphate/phosphoric acid 3. Nitrogen Base (4 types) Copyright Pearson Prentice Hall

The Components and Structure of DNA 3. There are four kinds of DNA nitrogen bases: Adenine Guanine Cytosine Thymine Purines: double ring DNA is made up of nucleotides. Each nucleotide has three parts: a deoxyribose molecule, a phosphate group, and a nitrogenous base. There are four different bases in DNA: adenine, guanine, cytosine, and thymine. Pyrimidines: single ring Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4. DNA is made up of a double strand of nucleotides held together with weak hydrogen bonds. 5. DNA has a double helix shape (twisted). Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA follows the “Base Pairing Rule” Adenine only bonds to Thymine Cytosine only bonds to Guanine Why? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA’s structure Was determined By James Watson and Francis Crick In 1953. Copyright Pearson Prentice Hall

The Components and Structure of DNA DNA Double Helix DNA is a double helix in which two strands are wound around each other. Each strand is made up of a chain of nucleotides. The two strands are held together by hydrogen bonds between adenine and thymine and between guanine and cytosine. Copyright Pearson Prentice Hall

The Components and Structure of DNA X-Ray evidence of DNA’s structure was provided by:  Rosalind Franklin and Maurice Wilkens -took an X-ray of DNA Rosalind aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film. This X-ray diffraction photograph of DNA was taken by Rosalind Franklin in the early 1950s. The X-shaped pattern in the center indicates that the structure of DNA is helical. Photo credit: ©Cold Spring Harbor Laboratory Archives/Peter Arnold, Inc. Copyright Pearson Prentice Hall

Nobel Prize winners in 1962 ~ Crick, Watson and Wilkens Died in 1958 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Watson: current head of the Human Genome Project Crick: died in 2004 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA Replication: -DNA makes an exact copy of itself -Why? So cells can divide and each new cell has an exact copy of DNA. -Occurs in all cells -Some cells lose the ability to divide. Example: nerve, brain, heart -Some cells divide all the time: Example: skin, bone Copyright Pearson Prentice Hall

-DNA replication requires enzymes. -Each chromosomes is over 20,000 nitrogen bases long so it happens in sections. Interesting but useless bits of knowledge: DNA is an invisibly thin, very long double strand of nucleotides. The DNA found in each human cell is almost 2 meters or 6 feet long. If all the DNA in a human adult were laid end to end the DNA molecule would stretch 113 billion miles. That would equal 610 trips to the sun and back. Copyright Pearson Prentice Hall

Steps to DNA Replication: DNA helicase unwinds and unzips DNA by breaking the hydrogen bonds between nitrogen base pairs at several places along each strand. Creating several “replication bubbles”. Copyright Pearson Prentice Hall

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Copyright Pearson Prentice Hall 3. Two DNA polymerase enzymes, one on each side of the DNA strand add new nucleotides following the base pair rule. Copyright Pearson Prentice Hall

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Copyright Pearson Prentice Hall 4. This continues until all “replication bubbles” converge to create 2 new DNA molecules. 5. The separate strands of DNA are joined with DNA ligase to create two continuous new strands. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 6. Two new strands recoil and two new, identical molecules are formed. T A G C A T C G T A G C A T C G Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall DNA Replication Copyright Pearson Prentice Hall

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