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DNA and RNA

DNA and RNA. DNA stands for Deoxyribonucleic Acid. In 1953, James Watson and Francis Crick developed the model called the Double Helix used to represent DNA. But what about Rosalind Franklin?. Rosalind Franklin.

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DNA and RNA

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  1. DNA and RNA

  2. DNA stands for Deoxyribonucleic Acid • In 1953, James Watson and Francis Crick developed the model called the Double Helix used to represent DNA. • But what about Rosalind Franklin?

  3. Rosalind Franklin • Photograph 51 is the nickname given to an X-ray diffraction image of DNA taken by Raymond Gosling in May 1952, working as a PhD student under the supervision of Rosalind Franklin, at King's College London in Sir John Randall's group. It was critical evidence in identifying the structure of DNA.

  4. What is inside of the Nucleus? • Chromosomes are threadlike structures that contain genetic information that is passed on from one generation of cells to the next. • Chromosomes are made up of DNA • Chromosomes are only visible during cell division. Otherwise genetic information is known as chromatin.

  5. Chromatin

  6. Parts of the chromosome • Centromere - the part of a chromosome that links sister chromatids • Chromatid - one copy of a duplicated chromosome, which is generally joined to the other copy by a single centromere. • Gene segment – segment of DNA that codes for a trait

  7. Chromosomes

  8. Where is Your DNA? DNA is coiled up to make chromosomesfound in the nucleus. A segment of DNA is a genethat codes for a certain trait. (skin tone, eye color)

  9. Regents Practice Question # 1 Which model best represents the relationship between a cell, a nucleus, a gene, and a chromosome?

  10. Regents Practice Question # 1 (Answer) Which model best represents the relationship between a cell, a nucleus, a gene, and a chromosome? Correct Answer

  11. Regents Practice Question # 2 Which diagram represents the relative sizes of the structures listed below?

  12. Regents Practice Question # 2 (Answer) Which diagram represents the relative sizes of the structures listed below? Correct Answer

  13. DNA • DNA is called the blueprint of life because it contains the instructions for building an organism and ensuring that organism functions correctly.

  14. Structure of DNA • DNA belongs to the class of biochemical molecules known as nucleic acids • This Twisted Ladder is made of nucleotides • The sides of the ladder are composed (made) of alternating deoxyribosesugars and phosphates. • The rungs of the ladder are composed of nitrogenous bases.

  15. A Nucleotide is the building block of nucleic acids. An organic compound made of one phosphate, nitrogenous base, and a sugar.

  16. Nitrogenous Base Pair • Adenine pairs to Thymine • Guanine pairs to Cytosine

  17. Your Turn A T T C G C G A A T T G T A A G C G C T T A A C T G G A T C C G T G A A A C C T A G G C A C T T

  18. DNA is Important • It carries genetic information from one generation to the next • DNA sequences create genes which then determine inherited traits • DNA can be easily copied during the creation of new cells

  19. DNA REPLICATION • Replication is the process where DNA makes a copy of itself. WHY? • During cell division the genetic information needs to be passed to the daughter cells

  20. DNA Replication Process • DNA separates into 2 strands unzipping itself with an enzyme called Helicase • One half of the old strand is always kept as a template for the new strand. DNA polymerase is an enzyme that matches nucleotides to old strand. • 2 daughter strands each consisting of an old DNA and a new DNA strand

  21. DNA Replication in Use

  22. DNA Fingerprintingor Gel ElectrophoresisA process used to compare DNA samples from different sources.

  23. DNA Fingerprinting(Gel Electrophoresis) Steps of DNA fingerprinting • DNA is cut using restriction enzymes, then fragments are placed in gel well • Electricity is applied to gel • DNA molecules move from negative to positive charged ends of gel • Smaller DNA segments move faster and farther than larger DNA segments

  24. Uses of DNA Fingerprinting • Solve crimes • Determine Paternity • Establish Evolutionary Relationships

  25. Proteins Synthesis • Genes control the production of proteins which occurs in the ribosomes. • Proteins are in every cell, tissue, muscle and bone – two million proteins in your body. • DNA can’t leave the nucleus but it needs to send instructions to the ribosomes so proteins can be made. • DNA sends a messenger out to the ribosome that carries the instructions for making the proteins.

  26. What is RNA? • Ribonucleic Acid - RNA is the messenger that carries the instructions to the ribosomes so proteins can be made. • Three Types of RNA mRNA-messenger tRNA-transfer rRNA-ribosomal

  27. Structure of RNA • Single stranded • It has uracil for a nitrogenous base instead of thymine • Complimentary base pairs are: • Cytosine-Guanine • Adenine-Uracil

  28. Making A Protein starts with Transcription • Transcription is the process where a DNA molecule makes the messenger RNA molecule in the nucleus so genetic instructions can leave the nucleus. • Done by copying part of the base sequence of the DNA into a strand of RNA • RNA polyermase unzips the DNA strand and matches up the nucleotides.

  29. Translation happens when mRNA arrives at the ribosome • Translation allows the cell to use information from mRNA to produce proteins that are built from amino acids • DNA mRNA Protein Transcription Translation

  30. Genetic Code • A codon consists of 3 nitrogenous bases that code for a single amino acid that is to be added to the growing protein chain. • Codons are located on the mRNA • There are just 22 different amino acids that exist.

  31. MUTATIONS • Mutations are changes in the DNA sequence that affect genetic information. • Mutations provide genetic variations in a species • Not all mutations are harmful, some give an advantage to a species

  32. Three Types of Mutations Mutations can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. • Substitution • Deletion • Insertion

  33. Substitution • Occurs when one nitrogenous base is substituted in place of another one

  34. Insertion • Occurs when one extra nitrogenous base is added into the DNA sequence

  35. Deletion • Occur when one nitrogenous base is missing from the sequence

  36. Causes of Mutations • Two ways DNA can be mutated: • Mutations can be inherited • Mutations can be acquired • Environmental damage • Mistakes when DNA is copied

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