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Cell Division

Cell Division. 2.5 Cell Division 3.3 DNA Structure 3.4 DNA Replication. 3.3 DNA Structure. Syllabus Statements : Outline DNA nucleotide structure of sugar ( deoxyribose ), nitrogenous base and phosphate group.

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Cell Division

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  1. Cell Division 2.5 Cell Division 3.3 DNA Structure 3.4 DNA Replication

  2. 3.3 DNA Structure Syllabus Statements: Outline DNA nucleotide structure of sugar (deoxyribose), nitrogenous base and phosphate group. State the names of the four bases in DNA (Adenine, Guanine, Cytosine, and Thymine). Outline how DNA nucleotides are linked together by covalent bonds into a single strand. Explain how a DNA Double Helix is formed using complimentary base pairing and hydrogen bonds. Draw and label a simple diagram of the molecular structure of DNA.

  3. 3.5 RNA Syllabus Statements: 3.5.1 Compare the structure of RNA and DNA.

  4. DNA/RNA Review Video

  5. The Nucleic Acids • Store and transmit hereditary, or genetic, information. • Contain hydrogen, carbon, nitrogen, oxygen, and phosphorus. • The monomers of nucleic acids are nucleotides, which contain three parts: a 5-carbon sugar, a phosphate group, and a nitrogen base. • Examples: Deoxyribonucleic Acid and Ribonucleic Acid

  6. Comparing DNA & RNA

  7. 17 Things You Should Know About DNA

  8. DNA & RNA Structure Game(s)

  9. 3.4 DNA Replication Syllabus Statements: Explain DNA replication in terms of unwinding the double helix and separation of the strands by helicase, followed by formation of the new complimentary strands by DNA polymerase. Explain the significance of complimentary base pairing in the conservation of the base sequence of DNA. State that DNA replication is semiconservative.

  10. DNA Replication Animation

  11. DNA Replication Involves “Unzipping” • DNA Replication is the process by which DNA copies itself. We would say that DNA is ‘self-replicating.’ DNA copies DNA. • The process of DNA Replication involves a number of important enzymes . . . We will focus on DNA Helicase and a group of enzymes called DNA Polymerases. • DNA Replication is considered ‘Semi-Conservative.’

  12. DNA Replication is Semi-Conservative

  13. Formation of Two Complimentary Strands • DNA replication will occur during cell division (interphase) within the nucleoplasm of the nucleus. • Replication requires free nucleotides or nucleoside triphosphates (A, T, C and G) that form the new DNA strands. With the help of the enzyme DNA Helicase, the original double-stranded DNA molecule with “unzip”. Helicase will break the hydrogen bonds holding complimentary base pairs together. (A2T, G3C). The unpaired nucleotides now act as ‘template’ strands.

  14. Formation of Complimentary Strands (continued) • As soon as the DNA becomes ‘unzipped’, free-floating nucleotides will be covalently bonded to nucleotides on the template strands. • Another enzyme, DNA polymerase, will catalyze this reaction (dehydration synthesis reaction). DNA polymerase will operate on both strands but in opposite directions. • This process can occur at multiple points (origin of replication or replication bubble) along the DNA strand.

  15. Significance of Complimentary Base Pairing • This pattern of DNA replication ensures that two identical copies of DNA are produced. Again . . . DNA replication is described as a semi-conservative process because half of a pre-existing DNA molecule is always saved (conserved).

  16. DNA & DNA REPLICATION TUTORIALS

  17. Extra (and a bit more detailed) DNA Replication Animation(s)

  18. 2.5 Cell Division Syllabus Statements: 2.5.1 Outline the stages in the cell cycle, including interphase (G1,S,G2), mitosis and cytokinesis. 2.5.2 State that tumors (cancers) are the result of uncontrolled cell division and these can occur in any organ or tissue. 2.5.3 State that interphase is an active (growth) period in the life of a cell, when many metabolic reactions occur, including protein synthesis, DNA replication and in increase in the number of mitochondria and/or chloroplasts. 2.5.4 Describe the events that occur in the four phases of mitosis (PMAT). 2.5.5 Explain how mitosis produces 2 genetically identical nuclei. 2.5.6 State that growth, embryonic development, tissue repair and asexual reproduction involve mitosis.

  19. 1. The cell becomes too large: • DNA/Information Overload • Exchange with the environment (traffic problems). 2. Repair and Growth (including embryonic dev.) 3. Reproduction: • Asexual Reproduction Why Do Cells Undergo Cell Division?

  20. ASEXUAL REPRODUCTION(RELIES ON MITOSIS/CELL DIVISION) Daughter cells are identical to parent cells

  21. Life Span of Human Cells

  22. CELL DIVISION(A Super Simple Overview)

  23. Interphase

  24. Sister Chromatids

  25. Prophase

  26. Metaphase

  27. Anaphase

  28. Telophase

  29. Cytokinesis

  30. http://outreach.mcb.harvard.edu/animations/cellcycle.swf • http://www.youtube.com/watch?v=7hQ5xXJSmK4&feature=related • http://www.youtube.com/watch?v=VGV3fv-uZYI Mitosis Animation(s)

  31. The cell cycle is controlled by dozens of regulatory proteins inside and outside the cell: • Internal regulators: proteins that respond to signals inside the cell. (ex. Cyclins) • External regulators: proteins that respond to signals outside the cell. Growth factors are important in wound healing and embryonic development. REGULATING THE CELL CYCLE

  32. http://outreach.mcb.harvard.edu/animations/checkpoints.swf Regulating the Cell Cycle(animation)

  33. Programmed cell death. Once apoptosis is triggered, the cell will begin a “self destruct” sequence. • Programmed cell death is important during embryonic development. Apoptosis

  34. Cancer cells don’t respond to signals regulating the cell cycle. • Cancer risk is increased through: genetics, tobacco use, radiation exposure, ultraviolet radiation, poor diet, viral infections, chemicals, pollution, etc. What is Cancer?(Uncontrolled cell growth) http://outreach.mcb.harvard.edu/animations/checkpoints.swf

  35. A tumor (neoplasm) is an abnormal growth of tissue that can be: Malignant: A usually fast-growing, sometimes fatal tumor that invades surrounding tissue and sheds cells that spread throughout the body, creating new tumors. Cancerous. Benign: A well-defined, slow-growing mass with smooth boundaries that simply grows in diameter. Not seriously harmful unless it’s size compresses surrounding tissues. Benign tumors are non-cancerous. Cells may break away from malignant tumors and spread throughout the body (Metastasis) What are Tumors?

  36. Biopsy: Surgical removal of cells/a mass for identification. • Surgery (Removal of a malignant tumor) • Radiation Therapy (kills cells) • Chemotherapy with anti-mitoticdrugs) • But . . . Sometimes there is no treatment. What are some of the Side Effects of Cancer Treatment? (Sterility, Hair Loss, Pain Destruction of non-cancerous cells, Nausea, Vomiting, Depression . . . ) How Do We Treat Cancer?

  37. Cancer Cells(Videos)

  38. Examples of Cancers and/or Benign/Malignant Tumors.

  39. My Shocking Story

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