Reproduction Chapter 5

1. ReproductionChapter 5 B. Gillis Science 300

2. Famous Cell Biologists (5.1) • Robert Hooke (1665) –first used the term “cell” • Anton van Leeuwenhoek (1680) – first to observe tiny living organisms; known as the father of microbiology • Robert Brown (1820) - discovered the nucleus in a cell

3. The Cell Theory (5.1) • 1) All living things are composed of one or more cells • 2) The cell is the fuctional unit of life • 3) All cells come from pre-existing cells

4. Types of Microscopes (5.1) • 1) Compound Light Microscope- uses light and two lenses, less than 2000X magnification, able to see entire cell and living organisms • 2) Transmission Electron Microscope- uses beams of electrons, up to 2,000,000X magnification, able to view organelles • 3) Scanning Electron Microscope- up to 400,000X magnification, 3D images

5. Two Types of Cells (5.2) • Prokaryotic cells have no organized nucleus. These are found in simple organisms like bacteria. Unicellular-one cell organisms • Eukaryotic cells have an organized nucleus and organelles. They can be found in complex organisms like humans.Multicellular-many cell organisms

6. Animal and Plant Cell (5.2) View the following animal and plant cell and pay attention to 1) what organelles are in both and 2) which can only be found in one http://www.cellsalive.com/cells/cell_model.htm

7. Gillis Lecture Notes • Cell division within the human body ( cells actively dividing) • Cell division in both Plants and Animals; primitive forms of life and complex forms • Different division rates (rapidly vs. no division) • Mitosis vs. Meiosis

8. 3 Functions of Cell Division (5.4)( Why do cells divide?) • 1) To Repair and Heal Tissue -Replacement of damaged cells and birth of new cells • 2) To Grow -Increase the number of cells (adulthood), growth relies on division not size • 3) To Reproduce the Organism- continue the species,

9. The Cell Cycle (5.5) The cell cycle represents the entire life of a cell.

10. Mitosis (5.5)

11. Mitosis Video http://www.cellsalive.com/mitosis.htm http://www.johnkyrk.com/mitosis.html

12. Difference between Asexual Reproduction and Sexual Reproduction • Asexual Reproduction- creating offspring that are genetically identical to the parent • Sexual Reproduction- offspring the result of two sex cells uniting to form a zygote • Zygote- fertilized egg

13. Asexual Reproduction

14. Types of Asexual Reproduction • Binary Fission- an organism splits into two equally sized offspring each having a copy of the parent’s genetic material Bacteria

15. Types of Asexual Reproduction • Budding- offspring begin as an outgrowth of the parent, then break off on their own Hydra

16. Types of Asexual Reproduction • Fragmentation- a new offspring is formed from a piece that broke apart from the parent. Starfish

17. Types of Asexual Reproduction • Spore Formation- small, identical cells (spores) are created within the parent. Each spore has the capability to develop into a mature organism. Spores

18. Types of Asexual Reproduction • Vegetative Reproduction- organisms produce runners which have the ability to develop another organism. Strawberry plants

19. Answers to Section 5.8 pg. 161 • 1. Asexual Reproduction- one parent, one cell divides into two identical cells • Sexual Reproduction- two parents, two cells fuse to form a unique cell • 2. Each new cell requires a copy of the original information. Each cell has the complete genetic info to be any of the specialized cells of the body. • 3. The zygote has a combination of genes from both parents, while the cell that undergoes mitosis is identical to its parent.

20. 5.8 Answers continued • 4. Binary Fission- organism splits into two equal-size offspring • Budding- the offspring begin as an outgrowth of the parent. • Spore Formation- the organism undergoes cell division to produce a duplicate cell. The spore is usually housed within the parent cell. • Fragmentation- a part of the organism breaks off from the parent and forms a new organism • Vegetative Reproduction- a section of a plant is used to grow a new plant. The section does not need to be removed from the original plant. • 5. a) fragmentation b) vegetative reproduction c) budding

21. Hormones • Hormones- chemical messengers produced in one part of the body and can affect cells in other parts of the body

22. Hormones • A hormone is released by one of about a dozen glands, travels through the blood until it reaches a cell with a receptor that it fits. Then, like a key in a lock, the hormone molecule attaches to the receptor and sends a signal to the cell. The signal may tell the cell to increase or decrease cell division and reproduction. • Do questions 1-5 on page 165

23. Answers to Section 5.10 pg. 165 • 1. Hormones are chemical regulators produced in one part of the body that affect cells in other parts of the body. • 2. The release of plant hormones can be stimulated by light or temperature. The release of human hormones can be stimulated by cell damage, stress, and blood sugar. • 3. Auxins are plant hormones that cause plant cells to elongate. Cytokinins are plant hormones that stimulate cell division.

24. 5.10 Answers continued • 4. Growth hormone triggers cell division and increases the production of new proteins. Low production in childhood can result in dwarfism. High production can result in giantism. • 5. Calluses form only in areas where cell damage has occurred the damage cells release chemical messengers, causing cells in the same area to begin dividing.