BIOLOGY 220 NOTES.docx - BIOLOGY 220 NOTES Chapter 1 Major...

BIOLOGY 220 NOTES
Chapter 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)—digress from the standard in the direction of
more— BETA cells (sensor) from the Islet of Langerhans in
pancreas detect movement >90 mg— insulin first
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 cells detect 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 stop
Blood 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, more
pressure, more oxytocin
CATASTROPHIC ENDINS UNLESS SOMETHING INTERVENES
1

BIOLOGY 220 NOTES
Chapter 2: The Chemistry of Life (pg. 41)
Elements- simplest form of matter to have unique chemical properties
Ions - 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- CATION
Ions 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) and
form 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)
-- ANTIOXIDANT s a chemical that neutralizes a FREE RADICAL.
BONDS
---Molecules- two are more atoms united by chemical bond
--- Compounds- molecules composed of 2 or more elements
A molecule is held together by forces called CHEMICAL BONDS.