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Chapter 2 BOT3015L Introduction to Autotrophs and Osmotrophs

Explore the world of autotrophs & osmotrophs in plant cells, understanding characteristics like plastids, vacuoles, and cell walls. Learn how osmosis affects plant cells and study essentials of cell division and compound light microscope basics.

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Chapter 2 BOT3015L Introduction to Autotrophs and Osmotrophs

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  1. Organisms able to synthesize nutritive substances required for growth (auto=self, troph=feed/grow) Organisms that take up nutritive substances required for growth by osmosis (osmo=take up from external, troph=feed/grow) Chapter 2BOT3015LIntroduction to Autotrophs and Osmotrophs Presentation created by Danielle Sherdan All photos from Raven et al.Biology of Plants except when otherwise noted

  2. Today • Review preparation and notebook organization • Plant cells • characteristics of plant cells • plastids • large central vacuoles • cell wall • effects of osmosis on plant cells • cell division • Compound light microscope basics • Review preparation and notebook organization • Plant cells • characteristics of plant cells • plastids • large central vacuoles • cell wall • effects of osmosis on plant cells • cell division • Compound light microscope basics

  3. ReminderPreparation for Class Prior to each class: 1. Read the lab materials 2. Drawing list 3. Review questions 4. Methods

  4. ****************************** 13 June 2005 Treatment of Brassica rapa plants with GA Time: 10:05 am _√__ Measure plant heights 1. _20_ mm 2. _40_ mm _√_ Apply 20 µl 100 µM GA to 1st leaf of plants 1, 2 and 3. ___ Apply 20 µl 10 µM GA to 1st leaf of plants 4, 5 and 6. ____ ……..etc.……. Notebook (left / right) Leave space in front for table of contents Left (thinking) Right (lab work) • Interpretations • Conclusions • Graphs • Ideas for future experiments • Answers to review questions and objectives • Observations • Solution preparation • Methods • Data collected during experiment

  5. Today • Review preparation and notebook organization • Plant cells • characteristics of plant cells • plastids • large central vacuoles • cell wall • effects of osmosis on plant cells • cell division • Compound light microscope basics

  6. Harvesting cork for commercial purposes Microscopy enables the discovery of cells Slices of cork. Drawing by Robert Hooke, who coined the term “cell” in the 1600s

  7. Modern cell theory The modern cell theory states that All living organisms are composed of one or more cells 2. Chemical reactions of living organisms take place within cells 3. Cells contain the hereditary information of the organisms of which they are a part, and this information is passed from parent cell to daughter cell 4. Cells arise from other cells

  8. Generalized diagram of a plant cell

  9. Cytoplasmic streaming of chloroplasts Considering their function, why would movement of chloroplasts by cytoplasmic streaming be advantageous?

  10. Amyloplasts store starch Amyloplasts in a bean root

  11. Put cells in a bath of concentrated solution Observing the vacuole

  12. Osmosis

  13. Under high external solute concentrations --External water potential decreases to below that inside the cell, thus osmotic water efflux from the cell. This process is plasmolysis. Plasmolysis Normal physiological conditions --Low external solute concentration --High internal solute concentration, thus positive pressure inside. --Positive pressure in the plant cell pushes against the restricting cell wall, like a water balloon in a cage.

  14. Today • Review preparation and notebook organization • Plant cells • characteristics of plant cells • plastids • large central vacuoles • cell wall • effects of osmosis on plant cells • cell division • Compound light microscope basics

  15. Mitosis and cytokinesis

  16. nuclear envelope forms around each set of chromosomes chromosome replication during S phase of cell cycle chromosomes align along metaphase plate and are attached to cytoskeleton Homologous chromosomes chromosomes condense and nuclear envelope degrades chromosomes are pulled apart to opposite poles, notice both sets are identical Mitosis (nuclear division)simplified diagram

  17. Cell division in plants occurs at meristems Onion root meristem located at tip of root

  18. Compare mitosis and meiosis

  19. Total number of cell divisions? Fill in ploidy level in above “cells” Crossing over? Pairing of homologs?

  20. Centromeres divide? How many daughter cells are genetically identical to original cell? Comparison chart II mitosis meiosis

  21. or triploid or tetraploid… or tetraploid or hexaploid…, but not triploid, why?

  22. Today • Review preparation and notebook organization • Plant cells • characteristics of plant cells • plastids • large central vacuoles • cell wall • effects of osmosis on plant cells • cell division • Compound light microscope basics

  23. Robert Hooke’s drawing of his microscope (1660s) Light from an oil lamp Water-filled glass globe as condenser Specimen mounted on a pin Focus by changing the distance between the specimen and the lens

  24. Compound light microscope components

  25. High resolution Low resolution High magnification Low magnification

  26. Important points when using microscopes • Using lens paper, clean eyepieces and objectives before and after each lab • Focus. • Place the mounted specimen on the stage • Set objective • Looking from the side, not in the ocular, bring the objective very close to the coverslip • Looking through the eyepiece, move the objective away from specimen with the course focus knob until it is in focus • Use fine focus to get the best view Coverslip always (a flat specimen (2-D) is optimal for compound light microscopes)

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