BIOLOGY 220 NOTESChapter 1: Major Themes of A and P (pg. 1)Homeostasis- ability to maintain stable internal condition-maintained by negative feedback and positive feedback *Negative Feedback Mechanisms digress from standard and then return to the standard. Capillaries- only place things enter and exit in cardiovascular because so thin(Average level of glucose in plasma of blood is 90 mg/100 ml of blood)-Right Side of Diagram- high sugar food (Dr. Pepper and a Snickers)—digressfrom the standard in the direction of more—BETA cells(sensor) from the Islet of Langerhans in pancreas detect movement >90 mg—insulinfirst messenger—target cell absorbs glucose from plasma—glucose used in cellular respiration (products are ATP + H2O + CO2)-Left Side of Diagram- haven’t eaten—glucose level too low—ALPHA cellsdetect decreasing—release glucagon—glucagon goes to target cell and tells it to release glucose, raising the glucose blood level back to standard.Other examples- calcium too high—THYROCALCITONIN; calcium too low-- PARATHORMONE*Positive Feedback digress from standard more and more- shut off (don’t go back to standard)- must have an opportunity to stopBlood clotting (can’t get certain birth control with family history of blood clotting disorder- continue clotting until you die)Childbirth- OXYTOCIN—more pressure, more oxytocin, morepressure, more oxytocinCATASTROPHIC ENDINS UNLESS SOMETHING INTERVENES1
BIOLOGY 220 NOTESChapter 2: The Chemistry of Life (pg. 41)Elements-simplest form of matter to have unique chemical propertiesIons- charged particles with uneven numbers of protons and electron-can consist of a single atom with a positive or negative charge or as large as a protein with many charges on it--Gains electrons for a negative charge- ANION vs loses electrons for a positive charge- CATIONIons with opposite charges are attracted to each other and tend to follow each other throughout the body.Electrolytes- substances that ionize in water (ACIDS, BASES, OR SALTS) andform solutions capable of conducting electricity--important for chemical reactivity (calcium phosphate incorporated into bone), osmotic effects (water content and distribution), and electrical effects (muscle and nerve function)Free Radicals- chemical particles with odd number of electrons--produced by some normal metabolic reactions (ATP-producing oxidation in MITOCHONDRIA)--combine with fats, proteins, and DNA- converting them to free radical and triggering chain reactions (can cause cancer and death of heart tissue)--ANTIOXIDANTs a chemical that neutralizes a FREE RADICAL.BONDS---Molecules-two are more atoms united by chemical bond---Compounds- molecules composed of 2 or more elementsA molecule is held together by forces called CHEMICAL BONDS.