repeatable experiments lead to enough confidence form this.
study of the body by systems
the sum total of all the physical and chemical reactions occuring in the body.
ability of an organism to sense, monitor and respond to changes
capacity of living cells to transmit a wave of excitment
levels of organization:
- organ system
smallest and most numerous structural units that possess and exhibit basic characteristics of living matter?
left and right sides are mirror images
- thoracic-r/l pleural, mediastinum(heart, major vessels, esophagus)
the relatively constant states maintained by the body. standing or staying the same
basic components of a feedback loop:
- sensor mechanism
- integrating or control center
- effector mechanism
negative feedback system
- control systems are inhibitory
- ex. feeling cold and the body shivering
positive feedback system
- control systems are stimulatory
- ex. childbirth and the production of oxytocin
of the 26 major elements how many are essential?
- 4(Carbon, Oxygen, Hydrogen, Nitrogen) make up 96%
equals the number of protons and neutrons
the number of electrons orbiting the atom determine whether the atom is active?
atoms with less than 8 e- in the outer shell will attempt to lose, gain, or share e- with other atoms to achieve stability
elements that contain the same number of protons but different number of neutrons
- result from unequal charge distribution on a molecule.
- very weak bond, and are polar
- ex. water
- 2 or more substances(reactants) combine to form a different, more complex substance(product)
- a breaking down of a compound which releases energy
- 2 different reactants exchange to form to new products
hydrolysis reaction....breakdown larger food molecules into smaller releasing energy
dehydration synthesis---build larger complex molecules from smaller units. requires energy in form of ATP
compounds composed of molecules that contain C-C or C-H covalent bonds
- have few C atoms and no C-C or C-H bonds
- ex. water, O2. CO2, electrolytes(acids,bases,buffers)
- release H when in a solution
- taste sour
or alkaline are electrolytes that when dissociated in solution shift the H+/OH- balance in favor of OH-
4 major groups of organic substances:
- nucleic acids and related molecules
3 types of carbohydrates
- monosaccharides(simple sugars)-glucose
- disaccharides(double sugars)
- polysaccharides(complex sugars)
- water insolube organic biomolecules-non polar
- triglycerides or fats
contain a sugar, nitrogenous base, and a phosphate group
a decomposition reaction where the addition of a water molecule breaks a bond
composed of 20 commonly occuring amino acids. only 8 are known as essential amino acids, they cannot be produced by the body.