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THE BIOLOGICAL BASIS OF LIFE

THE BIOLOGICAL BASIS OF LIFE. Chapter 3. Human Genome Project. In 1990 an effort began to sequence the entire human genome, which consists of some 3 billion bases comprising approximately 25,000 to 30,000 genes. The goal was achieved in 2003.

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THE BIOLOGICAL BASIS OF LIFE

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  1. THE BIOLOGICAL BASIS OF LIFE Chapter 3

  2. Human Genome Project • In 1990 an effort began to sequence the entire human genome, which consists of some 3 billion bases comprising approximately 25,000 to 30,000 genes. • The goal was achieved in 2003. • Scientists are still several years away from identifying the functions of many of the proteins produced by these genes.

  3. Human…Neanderthal? Genome Project • The Neanderthal Genome has been sequenced. • Read the press release from the Max Planck Society here SvantePaabo and a Neanderthal skull

  4. Evolutionary significance • Tiny differences in protein-coding sequences may explain why humans are susceptible to diseases like cholera, malaria, and influenza while chimpanzees apparently are not.

  5. Genetics • The study of gene structure and action, and the patterns of inheritance of traits from parent to offspring. • Genetic mechanisms are the foundation for evolutionary change. Human Genome Project Overview of Genetics

  6. The Cell • Cells are the basic units of life in all living organisms. • In some forms, such as bacteria, a single cell constitutes the entire organism. • Complex life forms (multicellular), such as plants and animals, are made up of billions of cells.

  7. Cells • Life on earth can be traced back 3.7 billion years to single celled organisms, such as bacteria and blue-green algae. • Eukaryotic cells, structurally complex cells, appeared 1.2 billion years ago. • A three-dimensional structure composed of carbohydrates, lipids (fats), nucleic acids, and proteins

  8. Cells • Somatic cells – celllular components of body tissues, such as muscle, bone, skin, nerve, heart, and brain • Gametes – sex cells involved in reproduction and not important as structural components of the body • Egg cells produced in female ovaries • Sperm cells produced n male testes • Zygote – union of sex cells to form the potential of developing into a new individual; in this way gametes transmit genetic information from parent to offspring.

  9. Structure of a Generalized Eukaryotic Cell

  10. DNA Structure • For a cell to work, it needs DNA to direct it. • An organism’s inheritance depends on the structure and function of DNA. • DNA is composed of two chains of nucleotides, comprising a double strand or double helix. • A nucleotide consists of a sugar, a phosphate, and one of four nitrogenous bases…

  11. Part of a DNA Molecule

  12. DNA Structure • Nucleotides form long chains. • The two chains are held together by bonds formed on their bases with their complement on the other chain. • Guanine(G) is the complement of Cytosine(C) • Adenine (A) is the complement of Thymine(T)

  13. The DNA Molecule • James Watson (left) and Francis Crick in 1953 with their model of the structure of the DNA molecule.

  14. DNA Replication • Cells multiply by dividing, making exact copies of themselves and enabling organisms to grow and injured tissues to heal. • Inside the cell, the DNA must replicate itself first before the cell can split apart.

  15. Enzymes • Replication begins when enzymes break the bonds between bases throughout the DNA molecule, separating two previously joined strands of nucleotides and leaving their bases exposed… Enzyme

  16. The DNA Replication Process • Enzymes break the bonds between the DNA molecule, creating two nucleotide chains that need complementary nucleotides. • Unattached nucleotides pair with the appropriate complementary nucleotide.

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