Tuesday, December 13, 2016

15.4 Chromosomal Disorders

Examples of different chromosomal disorders with Mr. Mabrey!

17.5 Mutations

Understanding the basics of mutations with Mr.Andersen!

19.1 Viral Structure

This video helps us to understand the basics of a virus, including viral structure!!

Monday, April 18, 2016

55.1 Energy flow


55.4 Nutrient Cycles





Taking Notes: typing or writing?

A little something to think about when you are trying to decide between hand writing or typing your notes.

http://www.npr.org/2016/04/17/474525392/attention-students-put-your-laptops-away?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20160417

Monday, March 28, 2016

Terrestrial Biomes 52.2 - Austin

If you missed Austin's Terrestrial Biomes presentation or need to refer back to it, I have uploaded it to google docs.  Click here to take a shortcut.


Wednesday, March 2, 2016

47.3 Cell Fate Blog Post

Cell Fate Specification

Definitions:


  • Differentiation—changes involved in the progressive diversification of the structure and function of cells Acquisition of the characteristics that allow different cell types to perform their functions.
  • Cell fate—what a cell will become (if left alone).
  • Potency—what a cell could become
  • Commitment—restriction in potency
  • Specification—labile state where a cell has reversibly acquired fate (potency > fate)
  • Determination—state where a cell has irreversibly acquired fate (potency = fate)
  • Determinant—a molecule that regulates cell fate
  • Morphogen—a molecule forms a gradient and regulates cell fate in a concentration dependent manner. 

I. Types of Specificaton


  1. Autonomous Specification 
    • Remove a cell and the cell types normally derived from that cell will not form.
    • Isolate a cell and it will form the cell types it normally would have.
  2. Conditional Specification
    • Remove a cell and the cell types normally formed by that cell will be contributed by other cells (compensation) 
  3. Syncitial Specification
    • Important in insects

II. Autonomous Specification 


  • Asymmetric distribution and inheritance of determinants 
  • Determinants typically cytoplasmic 
  • Determinants usually RNAs or proteins
    1. MACHO mRNA localized in yellow cytoplasm of tunicate embryo 
      • Antisense blocks muscle formation (=necessary)
      • Injected mRNA induces animal pole to form muscle (=sufficient) 
    2. SKN-1 protein localized in C. elegans EMS cell (pharynx derived from EMS) 
      • skn-1 loss-of-function mutant produces no pharynx (necessary)
  • Fucus contains cell wall determinants (handout)

III. Conditional Specification 


  • A cell’s fate is determined by its environment 

A. Cell interactions.

  • Contact with neighboring cells influence cell fate e.g. sea urchin 
    • Animal pole cells alone produce ectoderm only
    • Animal pole cells plus micromeres produce cell types normally derived from vegetal pole cells 
  • Stem Cells—cells that divide to maintain a self-renewing population, and contribute daughters that will differentiate. Can get progressive commitment. 

Thursday, February 11, 2016

40.3- Thermoregulation

40.3- Thermoregulation
·         Regulation of internal temperature
·         Endothermy- warmed by the heat of metabolism , internal heat source (humans)
o   Need more food
·         Ecothermy-  warmed by environment, external heat source (reptiles)
o   Need less food because food is scarce
o   Larger fluctuation in body temperature
o   Regulate body temperature by moving to shading and basking
·         Variation in body temperature
o   Poikilotherms
§  Variation, body temp varies with environment
o   Homeotherms
§  Same, constant body temp

o   Never use warm-blooded or cold- blooded
·         Balancing heat Loss and Gain
o   Figure 40.11
o   Integumentary (Skin)
§  Insulation- fat, hair, feathers
§  Circulatory Adaptation- vasoconstrictions, vasodilation
§  Countercurrent Exchanges
§  Cooling by Evaporation
          ·         Heat or Loss
§  Behavior Response
          ·         Migration, Hibernation
§  Adjusting Metabolic Heat Production
            ·         Vary heat production to match changing rates of heat lose
             o   Shiver
§  Acclimatization in Thermoney
·         Shedding
·         Changes in Lipids