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Biology PowerPoint Presentation

Biology

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Biology

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  1. Biology Copyright Pearson Prentice Hall

  2. DNA RNA Thymine Guanine Cytosine Hydrogen bond Adenine Uracil Replication Protein synthesis mRNA tRNA rRNA Transcription Translation Amino acids Ribosome Peptide bond Watson & Crick Chromatin histones Vocabulary

  3. 12–1 DNA • Scientists discovered that the nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next. Copyright Pearson Prentice Hall

  4. The Components and Structure of DNA The Components and Structure of DNA DNA is made up of nucleotides. A nucleotide is a monomer of nucleic acids made up of: • Deoxyribose – 5-carbon Sugar • Phosphate Group • Nitrogenous Base Copyright Pearson Prentice Hall

  5. The Components and Structure of DNA There are four kinds of bases in in DNA: • adenine • guanine • cytosine • thymine Copyright Pearson Prentice Hall

  6. The Components and Structure of DNA Chargaff's Rules Erwin Chargaff discovered that: • The percentages of guanine [G] and cytosine [C] bases are almost equal in any sample of DNA. • The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA. Copyright Pearson Prentice Hall

  7. The Components and Structure of DNA X-Ray Evidence  Rosalind Franklin used X-ray diffraction to get information about the structure of DNA. She aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film. Copyright Pearson Prentice Hall

  8. The Components and Structure of DNA The Double Helix  Using clues from Franklin’s pattern, James Watson and Francis Crick built a model that explained how DNA carried information and could be copied. Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other. Copyright Pearson Prentice Hall

  9. The Components and Structure of DNA DNA Double Helix Copyright Pearson Prentice Hall

  10. The Components and Structure of DNA Watson and Crick discovered that hydrogen bonds can form only between certain base pairs—adenine and thymine, and guanine and cytosine. This principle is called base pairing. Copyright Pearson Prentice Hall

  11. 12–1 Copyright Pearson Prentice Hall

  12. 12–1 Avery and other scientists discovered that • DNA is found in a protein coat. • DNA stores and transmits genetic information from one generation to the next. • transformation does not affect bacteria. • proteins transmit genetic information from one generation to the next. Copyright Pearson Prentice Hall

  13. 12–1 The Hershey-Chase experiment was based on the fact that • DNA has both sulfur and phosphorus in its structure. • protein has both sulfur and phosphorus in its structure. • both DNA and protein have no phosphorus or sulfur in their structure. • DNA has only phosphorus, while protein has only sulfur in its structure. Copyright Pearson Prentice Hall

  14. 12–1 DNA is a long molecule made of monomers called • nucleotides. • purines. • pyrimidines. • sugars. Copyright Pearson Prentice Hall

  15. 12–1 Chargaff's rules state that the number of guanine nucleotides must equal the number of • cytosine nucleotides. • adenine nucleotides. • thymine nucleotides. • thymine plus adenine nucleotides. Copyright Pearson Prentice Hall

  16. 12–1 In DNA, the following base pairs occur: • A with C, and G with T. • A with T, and C with G. • A with G, and C with T. • A with T, and C with T. Copyright Pearson Prentice Hall

  17. 12-2 Chromosomes and DNA Replication 12–2 Chromosomes and DNA Replication Copyright Pearson Prentice Hall

  18. DNA and Chromosomes Many eukaryotes have 1000 times the amount of DNA as prokaryotes. Eukaryotic DNA is located in the cell nucleus inside chromosomes. The number of chromosomes varies widely from one species to the next. Copyright Pearson Prentice Hall

  19. DNA and Chromosomes Chromosome Structure Eukaryotic chromosomes contain DNA and protein, tightly packed together to form chromatin. Chromatin consists of DNA tightly coiled around proteins called histones. DNA and histone molecules form nucleosomes. Nucleosomes pack together, forming a thick fiber. Copyright Pearson Prentice Hall

  20. DNA and Chromosomes Eukaryotic Chromosome Structure Chromosome Nucleosome DNA double helix Coils Supercoils Histones Copyright Pearson Prentice Hall

  21. DNA Replication Duplicating DNA  Before a cell divides, it duplicates its DNA in a process called replication. Replication ensures that each resulting cell will have a complete set of DNA. Copyright Pearson Prentice Hall

  22. DNA Replication During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template for the new strand. Copyright Pearson Prentice Hall

  23. DNA Replication New Strand Original strand Nitrogen Bases Growth Growth Replication Fork Replication Fork DNA Polymerase Copyright Pearson Prentice Hall

  24. DNA Replication How Replication Occurs DNA replication is carried out by enzymes that “unzip” a molecule of DNA. Hydrogen bonds between base pairs are broken and the two strands of DNA unwind. Copyright Pearson Prentice Hall

  25. 12–2 In prokaryotic cells, DNA is found in the cytoplasm. nucleus. ribosome. cell membrane. Copyright Pearson Prentice Hall

  26. 12–2 The first step in DNA replication is producing two new strands. separating the strands. producing DNA polymerase. correctly pairing bases. Copyright Pearson Prentice Hall

  27. 12–2 A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand? GCGAATTCG CGCTTAAGC TATCCGGAT GATGGCCAG Copyright Pearson Prentice Hall

  28. 12-3 RNA and Protein Synthesis 12–3 RNA and Protein Synthesis Copyright Pearson Prentice Hall

  29. 12–3 RNA and Protein Synthesis Genes are coded DNA instructions that control the production of proteins. Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA. RNA contains coded information for making proteins. Copyright Pearson Prentice Hall

  30. The Structure of RNA The Structure of RNA There are three main differences between RNA and DNA: The sugar in RNA is ribose instead of deoxyribose. RNA is generally single-stranded. RNA contains uracil in place of thymine. Copyright Pearson Prentice Hall

  31. Types of RNA Types of RNA There are three main types of RNA: messenger RNA ribosomal RNA transfer RNA Copyright Pearson Prentice Hall

  32. Types of RNA Messenger RNA (mRNA)carries copies of instructions for assembling amino acids into proteins. Copyright Pearson Prentice Hall

  33. Types of RNA Ribosomes are made up of proteins and ribosomal RNA (rRNA). Ribosome Ribosomal RNA Copyright Pearson Prentice Hall

  34. Types of RNA During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome. Amino acid Transfer RNA Copyright Pearson Prentice Hall

  35. Protein Synthesis DNA molecule DNA strand (template) 5¢ 3¢ TRANSCRIPTION 5¢ 3¢ mRNA Codon TRANSLATION Protein Amino acid

  36. Transcription Transcription DNA is copied in the form of RNA This first process is called transcription. Copyright Pearson Prentice Hall

  37. Transcription RNA RNA polymerase DNA Copyright Pearson Prentice Hall

  38. The Genetic Code The Genetic Code The genetic code is the “language” of mRNA instructions. The code is written using four “letters” (the bases: A, U, C, and G). Copyright Pearson Prentice Hall

  39. The Genetic Code A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid. Copyright Pearson Prentice Hall

  40. The Genetic Code Copyright Pearson Prentice Hall

  41. Translation Translation Translation is the decoding of an mRNA message into a polypeptide chain (protein). Translation takes place on ribosomes. During translation, the cell uses information from messenger RNA to produce proteins. Nucleus mRNA Copyright Pearson Prentice Hall

  42. Translation The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA. Lysine Phenylalanine tRNA Methionine Ribosome mRNA Start codon Copyright Pearson Prentice Hall

  43. Translation Protein Synthesis Lysine tRNA Translation direction mRNA Ribosome Copyright Pearson Prentice Hall

  44. Translation The process continues until the ribosome reaches a stop codon. Polypeptide Ribosome tRNA mRNA Copyright Pearson Prentice Hall

  45. Genes and Proteins DNA mRNA Protein Codon Codon Codon Single strand of DNA Codon Codon Codon mRNA Alanine Leucine Arginine Amino acids within a polypeptide Copyright Pearson Prentice Hall

  46. 12–3 The role of a master plan in a building is similar to the role of which molecule? messenger RNA DNA transfer RNA ribosomal RNA Copyright Pearson Prentice Hall

  47. 12–3 A base that is present in RNA but NOT in DNA is thymine. uracil. cytosine. adenine. Copyright Pearson Prentice Hall

  48. 12–3 The nucleic acid responsible for bringing individual amino acids to the ribosome is transfer RNA. DNA. messenger RNA. ribosomal RNA. Copyright Pearson Prentice Hall

  49. 12–3 A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the intron. exon. promoter. codon. Copyright Pearson Prentice Hall

  50. A codon typically carries sufficient information to specify a(an) single base pair in RNA. single amino acid. entire protein. single base pair in DNA. 12–3 Copyright Pearson Prentice Hall