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AP Biology

AP Biology. During development an organisms cells differentiate from Stem cells Stem cell – any unspecialized cell that can produce, during a single division one identical daughter cell and one more specialized daughter cell This occurs via structural and functional divergence of cells.

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AP Biology

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  1. AP Biology

  2. During development an organisms cells differentiate from Stem cells • Stem cell – any unspecialized cell that can produce, during a single division one identical daughter cell and one more specialized daughter cell • This occurs via structural and functional divergence of cells Cell Specialization

  3. Molecular level (chemicals) • Cell • Tissue • Organ • Organ system • Organism Cellular organization

  4. Form and Function

  5. Negative – Reduces frequency, regulates physiological processes back to a target set point (long term) • Positive – Increase frequency or amplify processes (short term) Positive and Negative feedback

  6. Regulator Vs Conformer Temp. regulation

  7. To become attractive plants produce fruit, this makes them desirable so animals will take and carry off their seeds. Plants communicate via ethylene – a gas

  8. Lactation in mammals – When baby drinks milk, hormones prolactin and oxytocin are released, this causes milk to be released and produced. • Child birth – pressure on cervix causes contractions. Contractions cause more pressure • Blood clotting – vascular spasms Decrease blood flow, plug formation, coagulation Other Positives

  9. Some changes to homeostasis are regulated and many are controlled by hormones. • Examples: • Women’s menstrual cycle • Circadian rhythm (changes that occur every 24 hours) • Acclimation- gradual process in which animal adjusts to external environment Alteration of feedback 

  10. Normal alterations

  11. Thermoregulation – process by which animals maintain an internal temperature • Endothermic – warmed by heat they generate via metabolism • Ectothermic – gain heat via external sources Maintaining homeostasis physiological

  12. Balancing Heat Loss and gain • Integumentary system • Insulation • Circulatory adaptations • Cooling via evaporative heat loss Maintaining homeostasis

  13. Increases blood flow to help keep warm • Decreases blood flow to help keep cool Maintaining homeostasis

  14. Countercurrent exchange- exchange of heat via fluids or between fluids that are moving in the opposite direction Maintaining homeostasis

  15. Maximize sunlight absorption • Postures • Huddling together • Torpor • Hibernation Maintaining homeostasis behavioral

  16. Form and Function

  17. Homeostatic disruptions are anything that affects the individual or the environment in which the individual lives in • Can be: • Molecular level • Ecosystem level Disruptions In Homeostasis

  18. Problem in feedback loops • Can be • Type I (juvenile or child onset) • Type II • Both cases cells are not communicating in the feedback loop dealing with blood sugar Diabetes

  19. Diabetes Insulin Blood glucose glucagon Alteration of feedback 

  20. Dehydration: Molecular disruption

  21. Molecular disruption

  22. Invasive species: A species, often introduced by humans, that takes hold outside its native range Ecosystem disruptions

  23. Form and Function

  24. Response: Anything an organism does as a result of its surroundings • Can be: • Behavioral • Physiological Form and Function

  25. Occurs as a population or a group of organisms • Examples: • Hibernation • Migration Can be learned or inherited Behavioral Responses

  26. Changes within the organism • Examples: • Shivering • Sweating- evaporative cooling Physiological responses

  27. Form and Function

  28. Plants and animals defend themselves from pathogens • Pathogens- invaders • 2 major forms of defense: • Nonspecific • Specific Physiological-Defense

  29. Kills anything that invades (skin, saliva, normal bacteria, swelling, inflammation etc.) • Plants sense pathogens using Hypersensitive Responses Nonspecific

  30. R gene in chromosomes – senses invading proteins • R gene will initiate a hypersensitive response • Oxidative burst – apoptosis • Proteins sent to adjacent cells will change cell wall • Memory does not occur Nonspecific - hypersensitive

  31. Specific responses identify pathogens and attack them • Occurs in 2 forms: • Humoral – occurs in humor/liquid/blood/lymphatic • Cell mediated – target infected cells Specific

  32. Humoral responses are governed by B cells • B cells produce memory Antibodies • Antibodies target invaders • Invaders are called antigens - Humoral

  33. Antibodies have antigen-binding sites • Antigen- is an antibody generating organism • fungus, bacteria, virus etc. Humoral

  34. Antigen present – invader • Antigen is engulfed (eaten) by a WBC or macrophage • WBC will take some of the antigen and put it on the surface of its cell (Antigen Presenting Cell) • Helper T cells- recognize the shape of the antigen • Helper T cells- activate B cells to make antibodies a. plasma B – makes antibodies b. memory B 6. B cells invade antigens Humoral

  35. This response targets infected cells • Called cytotoxic T cells – kills own cells that are infected Cell-mediated

  36. Form and Function

  37. How does this happen? Physiological- Development

  38. Seed Germination – • When planting seeds it needs 2 things to survive (water and temperature) must be in correct combination • Germinating cells will appear different Physiological

  39. First step in development is cellular differentiation • DNA will express specific proteins that determine each tissue – called tissue specific proteins • Cells will eventually specialize Physiological

  40. Zygote makes a copies of itself • Forms a sphere (blastula) • Blastula folds in on itself (gastrula) forms ectoderm, mesoderm and endoderm • Transcription factors give off proteins that help to determine what should happen Physiological - differentiation

  41. Step 2 is embryonic induction: • Cells induce other cells to become like them, give off proteins • Cells induce adjacent cells next to it Physiological - induction

  42. Just as important as cell growth • Hid, Grim, Reaper Genes • These genes are needed between fingers and toes etc. • microRNA genes – control hid, grim, reaper genes Physiological – cell death

  43. How do cells “know” the body plan of organisms? • Homeotic genes – are a series of genes that “tell” drosophila where to put the organs/appendages etc. • Famous ones are HOX genes We learned from the mutants Ultrabithroax will duplicate the thorax Antp- one leg will grow of the head Series of genes that codes for body plan Physiological- Homeotic genes

  44. Form and Function

  45. When traveling – especially across time zones jet-lag occurs Timing and control

  46. Phototrophism – how plants grow toward or away from light Toward light + Away from light – Hormone: Auxin Timing and control - plants

  47. Photoperiodism – how plants respond to changing amounts of light during the season Phytochrome – light receptor- when absorb light, will change shape to let plant know what time of day and season it is (regulates cellular activities) Timing and control - plants

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