scientific explanations are based on empirical evidence
empirical evidence :
-
based on the senses
-
obtained from observation/experimentation hypothesis :
not an "educated guess"
scientific method ~ can make predictions
-
make observation & ask question - is testable
-
hypothesis - is falsifiable
-
make predictions can be supported/fail to be supported
~
experiment & observe
-
draw conclusions & share findings
theories
- broad ,
evidence-based graph title :
~ can use to generate hypotheses Y (independent) Us X (dependent
Science is neither dogmatic/infallible e g
. .
growth us
He
sample size :
define level of precision required
"double blind"
-
both researchers & subjects don't know categories
~
avoids bias and placebo effect
if people suffering from disease , can't withhold treatment
~ give patients treatment AND placebo or drug
correlation - causation <Pirates v S
. . global warming
null hypothesis -
Ho ,
there is no significant difference between groups
⑭IIIIIIII .theman a an
means very susceptible to outliers -
look at standard deviation
93 % confidence interval
~
range of values in which 95 % chance true mean lies in sample population interval
bigger N =
narrower interval more sure about true mean
,
smaller standard deviation =
narrower interval
P-value :
% probability that two groups aren't significantly different
,③s
4 elements make up 96 % weight of many living organisms
-
caryon , hydrogen ,
Oxygen , nitrogen
ions w/ opposite charges attract
-
"Salt"
Covalent strongest (share outside electrons ( main properties :
-
forms molecules
-
cohesive
electronegativity thermo-stable
& ull for electrons
-
:
-less dense as solid
polarity
- similar electronegativity :
nonpolar
-
unique solvent
~
different electronegaties :
polar
Water is polar ,
O slightly neg ,
I slightly pos
*
~
has dipole moments
pos &
Water
~
neg stick
:
He
together
sticks to 02 ,
02 sticks to H
+
G
Water's polarity makes it cohesive
~
related to surface tension
-
how hard it is to break a liquid surface
9 water molecule
>
-
plant get water
Water's hydrogen bonds moderate temperature
-
high specific heat ,
hard to change temp
↑ covalent
----
~
stable internal environments !
o
-
water cools things when it evaporates
i ce less dense than water
- loating ice allows animals to live (acts as insulation (
-. ju
hydrogen
⑪ " bond
-
Water :
solvent of life
⑪
-
polar solutes dissolve
PH-how acidic/basic a substance is
. how
b water sticks to
- each H unit :
1ox change
itself (cohesions
- acidic-HT ,
basic-OH-
buffer : minimizes changes in PH
burning fossil fuels release CO2
, Des
carbon-based molecules :
organic compounds monomer
large biological molecules Macromolecules
⑧
:
- also called polymers (made from identical building blocks) polymer
building blocks monomers
⑧
- :
dehydration reactions
I
:
- remove water
-
links monomers mediated by
enzymes
hydrolysis
- add Water
-
break up polymers
sugars :
Monomers of carbohydrates
-
sugar-sugar-sugar-sugar - Starch
4 important to organisms
-
carbohydrates (sugar , starch)
- proteins (enzymes ,
muscles Carbohydrates :
-
lipids (fa + s) a hydrated carbon !
- nucleic acids (DNA ,
RNA)
carbohydrates
called monosaccharides "simple sugars "
monomers ,
monosaccharides form disaccharides , "complex sugar"
sugars : -
Ose // enzymes : -ase
9) Incose + frucrose =
sucrose
glucose-glucose- maltose
9) Incose + galactose =
lactose (milk)
biological functions :
-
energy
-
sugars are #1 source of ready energy
~
polysaccharides are used to store sugar when it isn't needed
-
plants make starch
- animals make glycogen
~ structure
~ cellulose (lots of glucose) for cell walls , wood ,
etc .
proteins
made from amino dcids
~
only 20 amino dcids !
~ carboxylic acid & amino group
~ dehydration reaction
~ find C = 0 , then C-N is peptide bond
cells have instructions to build proteins
shape of protein determines its function
denaturation -
chain unravels , loses shape + loses function