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DNA - Introduction

DNA - Introduction. Deoxyribonucleic Acid Structure: Replication Transcription Translation. DNA. DNA- Deoxyribonucleic Acid. What is this?. POLYMER. A polymer is a large molecule made up of smaller molecules called monomers DNA is a polymer made up of Nucleotides. NUCLEOTIDES.

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DNA - Introduction

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  1. DNA - Introduction • Deoxyribonucleic Acid • Structure: • Replication • Transcription • Translation

  2. DNA • DNA- Deoxyribonucleic Acid

  3. What is this?

  4. POLYMER • A polymer is a large molecule made up of smaller molecules called monomers • DNA is a polymer made up of Nucleotides.

  5. NUCLEOTIDES • Nucleotides are the smaller sub-units that make up a DNA • Each Nucleotide is made up of a • Sugar, Phosphate and Nitrogen Base

  6. 4 NITROGEN BASES

  7. Complementary Base Pairs: • Cytosine always bonds with guanine by forming three hydrogen bonds. (C-G) • Adenine always bonds with thymine by forming two hydrogen bonds. (A-T)

  8. DOUBLE HELIX • The DNA molecule consists of two nucleotide chains that wrap around each other to form a double spiral • Looks like a twisted ladder

  9. DNA makes you UNIQUE :) • The order of nucleotides (NB) will vary in every organism • The closer you are in Evolutionary History- the closer your DNA will resemble • The sequence of nucleotides forms the unique genetic information of an organism

  10. DNA Replication: • The process of copying DNA • Takes place during the “S” phase of the cell cycle…Remember?

  11. Steps of DNA Replication • DNA will unwind • DNA will “unzip” down the middle separating the sides of the ladder

  12. Steps of DNA Replication • Free-Floating nucleotides will come in and attach to each existing side of the original DNA • This process will continue until the entire molecule has replicated

  13. Outcome of DNA Replication • Replication will make 2 identical strands of DNA which can then be passed on to a new cell during mitosis or meiosis • When all the DNA in all the cells has replicated, there are 2 copies of the organism’s genetic information.

  14. DNA • DNA is the “Master” copy of an organisms information code. This information contains instructions used to form nearly all enzymes and proteins.

  15. DNA- Major Functions • Directing Protein Synthesis • Controlling Cell Division • Inheritance

  16. Why is it called Universal? • The codons represent the same amino acids in all organisms • Same in humans and virtually every other known organism • Figured out by studying the DNA of the bacteria E. Coli

  17. The Other Nucleic Acid- RNA • RNA stands for Ribonucleic Acids • RNA and DNA are very similar but they do have three key differences.

  18. RNA: Single Sided Sugar molecule called RIBOSE 4 Bases- Cytosine, Guanine, Adenine and URACIL DNA: Double sided Sugar molecule called DEOXYRIBOSE 4 Bases-Cytosine, Guanine, Adenine and THYMINE Differences between RNA & DNA

  19. RNA!! • RNA in involved in an important process called transcription. • The process in which RNA makes a copy of DNA • Similar to Replication.

  20. Transcription!! • Proteins are made on ribosomes in the cytoplasm of the cell. Yet DNA is found only in the nucleus. How is information brought to the ribosomes for protein synthesis?

  21. RNA Transcription . • DNA must first unwind. • Enzymes unzip DNA molecule • Free-floating RNA nucleotides pair with complementary DNA nucleotides on one of the DNA strands • Guanine pairs with Cytosine • Adenine pairs with Uracil

  22. RNA Transcription . • When the process of base pairing is completed, the mRNA molecule breaks away as the DNA strands rejoin • The mRNA leaves the nucleus and enters the cytoplasm to a ribosome.

  23. RNA Transcription • (Messenger) mRNA is the form in which information moves from DNA in the nucleus to the ribosomes in the cytoplasm • Enzymes make a RNA copy of a DNA strand

  24. DNA Start to Finish

  25. The Genetic Code • DNA holds the instructions to make proteins. • Like DNA..Protein is also a polymer made up of smaller subunits called Amino Acids • There are 20 A.A. They combine in various ways to make various proteins.

  26. The Genetic Code • You need to look at DNA as being similar to the alphabet. • The alphabet has 26 letters which combine to form 1000’s of words. • The DNA alphabet only has 4 letters and all the words are made up of only 3 letters. • When you “read” DNA you read in group of 3 Nitrogen Bases at a time. • Groups of 3 are called CODONS • Each codon will code for a specific Amino Acid

  27. Translation- Protein Synthesis • The process of converting the information of mRNA into a sequence of Amino Acids that will make a protein • On your ribosome is your mRNA with all the codons and information from DNA

  28. Another Form of RNA • tRNA • Transfer RNA • Single strand • Purpose is to bring the appropriate amino acid to the ribosome • Carries the anti-codon

  29. Mutations • Gene: sequence of DNA nucleotide bases • Gene Mutation: any change in this DNA sequence of nucleotide bases • Point Mutation: a change in a single base pair, mistake may or may not interfere with protein function • Frameshift Mutation: where a single base pair is added or deleted, this causes a shift in the reading of the codons by one base • These mutations can occur when the DNA is replicated, during transcription and translation

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