chapter 2 bot3015l introduction to autotrophs and osmotrophs
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Chapter 2BOT3015L
Introduction to Autotrophs and Osmotrophs
Presentation created by Danielle SherdanAll photos from Raven et al. Biology of Plants except when otherwise noted
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)
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
ReminderPreparation for Class
Prior to each class:1. Read the lab materials2. Drawing list3. Review questions4. Methods
Notebook (left / right)
Left(thinking)
Right(lab work)
• Observations• Solution preparation• Methods• Data collected
during experiment
•Interpretations•Conclusions•Graphs•Ideas for future experiments
•Answers to review questions and objectives
Leave space in front for table of contents
******************************13 June 2005
Treatment of Brassica rapa plants with GA
Time: 10:05 am
_√__ Measure plant heights
1. _20_ mm2. _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.…….
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
Microscopy enables the discovery of cells
Slices of cork. Drawing by Robert Hooke, who coined the term “cell” in the 1600s
Harvesting cork for commercial purposes
Modern cell theory
The modern cell theory states that 1. All living organisms are composed of one or
more cells 2. Chemical reactions of living organisms take
place within cells
4. Cells arise from other 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
Generalized diagram of a plant cell
Cytoplasmic streaming of chloroplasts
QuickTime™ and aCinepak decompressor
are needed to see this picture.
Considering their function, why would movement of chloroplasts by cytoplasmic streaming be advantageous?
Amyloplasts store starch
Amyloplasts in a bean root
Observing the vacuolePut cells in a bath of concentrated solution
Osmosis
Plasmolysis
--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.
Normal physiological conditions 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.
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
Mitosis and cytokinesis
Mitosis (nuclear division)simplified diagram
chromosomereplication during S phase of cell cycle
chromosomes condense and nuclear envelope degrades
chromosomes align along metaphase plate and are attached to cytoskeleton
chromosomes are pulled apart to opposite poles, notice both sets are identical
nuclear envelope forms around each set of chromosomes
Homologouschromosomes
Cell division in plants occurs at meristems
Onion root meristem located at tip of root
Compare mitosis and meiosis
Total number of cell divisions?
Fill in ploidy level in above “cells”
Pairing of homologs?
Crossing over?
Comparison chart II mitosis meiosis
Centromeres divide?
How many daughter cells are genetically identical to original cell?
or triploid or tetraploid… or tetraploid or hexaploid…, but not triploid, why?
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
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
Compound light microscope components
High resolution Low resolution
High magnification Low magnification
Important points when using microscopes
• Using lens paper, clean eyepieces and objectives before and after each lab
Coverslip always (a flat specimen (2-D) is optimal for compound light microscopes)
• Focus.1. Place the mounted specimen on the stage2. Set objective3. Looking from the side, not in the ocular, bring the
objective very close to the coverslip4. Looking through the eyepiece, move the objective
away from specimen with the course focus knob until it is in focus
5. Use fine focus to get the best view
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