Transcript Scientific Method

Topic: The
Science of
Life/Chemistry
Characteristics of Living
Organisms
•
•
•
•
•
•
•
Organization
Cells
Response to stimuli
Homeostasis
Metabolism
Growth and development
Reproduction
• Evolution—not a charac but important
Unity in the Diversity of Life
•
Three Domains of Life
° Bacteria
° Archaea
° Eukarya (contains nuclei)
–The six kingdoms include
Archaea, Bacteria, Protista,
Fungi, Plantae, and Animalia.
Unity in the Diversity of Life
Scientific Method
•
•
Not rigid, order/details may vary
2 types of data:
–Quantitative = use #’s
–Qualitative = use descriptive
words
Scientific Method
•Collecting observations
•Asking questions
•Forming hypotheses and
making predictions
•Confirming predictions (with
experiments when needed)
•Drawing conclusions
Controlled Experiment
•
•
Compares an experimental group
and a control group and only has
one variable – keeps all other
factors the same
Control Group - used for
comparison (unchanged), part of
controlled exp.
Scientific Method
–theory is a set of related hypotheses
confirmed to be true many times,
and it can explain a great amount of
data.
Scientific Method
•
Publishing a Paper
–Scientists submit research papers to
scientific journals for publication.
–In peer review, the editors of a
journal will send submitted papers
out to experts in the field who
anonymously read and critique the
paper.
–Primary source
Scientific Method
•
Models
– Explanation supported by data
– May be visual, verbal, mathematical
•
Graphing
– Good visual organization
– Must contain a Descriptive Title, label
both axes and include units
° Dependent variable goes up Y axis
Microscopy
•
•
•
Magnification: apparent size
Resolution: clarity of details
Power of Magnification:
–Ocular (eyepiece) X Objective =
total mag.
–Actual size =
mag. size /magnification
Microscopy
Light
Microscope
•
Limited
magnification
Transmission Electron
Microscope (T.E.M.)
•
•
•
•
Aims a beam of electrons instead
of light waves THROUGH
a specimen
200,000 times better
than the eye
Looks at internal structure
No living specimens
Scanning Electron Microscope
(S.E.M.)
•
•
•
Bounces electrons
off specimen's
surface
No living
specimens
Look at surface of
structure
Building Blocks of Matter =
CH 2
• Matter is anything that
occupies space and has
mass.
•
Mass is the quantity of
matter an object has
Atomic Structure
Nucleus = protons
(+) and neutrons (0)
• Electrons (-) = in
clouds around the
nucleus, at varying
energy levels
•
maximum
Atomic Elements
The type of atom is
determined by the
number of protons
in its nucleus.
• Atomic Number = #
protons and #
electrons
• CHONP = 90% of all
living things
Atoms Combine to Form:
•
Elements: substances made of
only one type of atom
– Coal, diamond, gold
•
Molecules: two or more atoms
bonded together
– Oxygen gas, O2, and water,
H2 O
O C O
Atoms Combine to Form:
•
Compounds: two or more different
atoms bonded together
of different elements
• NaCl (salt)
• H2SO4 (sulfuric acid)
Ionic Bonding
•
•
Within a molecule: Weaker Bond
Results from a transfer of electrons from
one atom to another
– ions: charged atoms
Covalent Bonding
•
•
Within a molecule: STRONG BOND
Results from a sharing of electrons
between atoms
Carbon Atom—Can
bond with 4 other
elements
Hydrogen Bonding
•
Between molecules:
•
Results from attraction between N,O
and H in different molecules
–Weakest single bond: strong when all
summed
together
Polar Covalent Bond
STRONGEST BOND
•
•
•
Unequal sharing of electrons between
atoms results in positive and negative
“poles”
overall net charge = 0
Found in WATER
Chemical Reactions-CH 2
•
Reactants go into equation and
products come out
6CO2 +12H2O+Sun ----> C6H1206 + 6H2O + 6O2
•
Reactants ----> Products
Reactions
•
•
Most reactions are reversible
Reversible reactions will approach
dynamic equilibrium
Reactions Absorb or
Release Energy
•
•
•
Reduction-Oxidation
Reactions
Energy is often transferred through
electrons = redox reaction…happen at
the same time
Oxidation = LOSS of an electron
(becomes a + ion like Na+)
Reduction = GAIN of an electron
(becomes a negative ion like Cl-)
Properties of Water
•
Unique properties good for living
things:
–Adhesion and Cohesion allow it to
travel up a plant, creating:
°Capillary Action
–cohesion = water + water
–adhesion = water + non water
Ionization of Water
•
•
•
•
In water, O can pull an H off
another water molecule
Results in OH- (hydroxide ion) and
a H+ (hydrogen ion)
H+ immediately reacts with another
water to form H3O+ (hydronium ion)
If # of OH- = # of H3O+ (H+) solution
is neutral (pH 7)
Acids & Bases
•
Acids = solution with more H3O+ (H+)
than OH–sour & corrosive
–acidic
•
Bases = solution with more OH- than
H3O+
–bitter & slippery
–Basic or alkaline
pH Scale
•
•
•
•
Compares relative concentration of
_
hydronium (H3O+ ) to hydroxide ions (OH )
Ranges 0 to 14
Ends of scale = strong, middle is weak
Log scale = each number difference is factor
of 10 (ex. 4 has 10X more H3O+ than 5 and
100X more H3O+ than 6)
Measuring Acidity
Buffers
•
•
Help hold pH constant
Most enzymes can only function in
a narrow pH range
ATP
•
Adenosine triphosphate
– Composed of adenine, ribose, and
three phosphate groups
– Cell's chief energy source.
The ATP
ADP Cycle
•
Energy input links phosphate to ADP to
produce ATP
•
ATP + catalyst ---> ADP + P + energy
•
ADP + P + energy ---> ATP
(sunlight,
chemical energy)
Organic Compounds = CH 3
•
Compounds that have:
– Carbon atoms covalently bonded
to each other and to H, O, N, P, S
(CHNOPS)
Carbon Bonds
Functional Groups
•Usually found at end of carbon chains or
regularly interspersed, influence the
properties of the molecules they compose
Hydroxyl (COH)
slightly hydrophillic
Aldehyde (COH)
slightly hydrophillic
P
Ketone (CO)
slightly hydrophillic
Carboxyl (COOH)
Phosphate (PO4)
Moderately hydrophillic
slightly hydrophillic
Monomers to
Polymers
•
Condensation (aka
dehydration
synthesis) links
monomers,
produces water
•
Hydrolysis breaks
polymers apart –
uses water
Carbohydrates =#1
•
•
•
Are sugars
Made of C, H, O
Can be mono, di, or polysaccharide
Carbohydrates
(sugars)= #1
Simple sugars =
monosaccharide (one) is
monomer
Ex: glucose, fructose =
C6H12O6
Disaccharides
•
Made from joining 2 mono’s
together
– Glucose +
fructose = Maltose
° Mono +
Mono = Di
° Must take out a WATER molecule (H and OH) between
each mono to join together to make a DI
•
•
Polysaccharides
Storage (3+ monos)
(starch=plant,
glycogen=animal)
Structural support
(cellulose, chitin)
Saccharide Formation
•
Condensation links monosaccharides
Proteins = #2
•
•
•
•
•
Made of C, H, O, N
Chains of amino acids
A.A. = monomer
Globular shape
Carbon backbone, carboxyl,
amine & a functional (R) group
Functional Groups
Protein Formation
•
•
Condensation makes peptide bonds
Water is produced as a result of rxn
Proteins
Often in complex and
unique shapes due to H
bonds, temp., solvent etc
• Are your hair,
Muscles, nails,
Enzymes!
-Function: provide
Protection; run chem rxns
•
Lipids = #3 (fats, oils, and waxes)
•
•
•
Made of C, H, O
Made of glycerol and fatty acids (looks
like an “E” with long chains of F.A’s
Fatty acid = carbon chain +
carboxyl unit
O
C
•
C
C
C
C
C
Types of Lipids:
– Phospholipid= 2 fatty acids w/ one glycerol
– Triglyceride= 3 fatty acids combined w/ one
glycerol
OH
Lipids (fats, oils, and waxes)
•
•
LONG hydrocarbon chains, that are
insoluble in water (non polar)
Fats have 6 times more energy
than starch, carry more energy-rich
bonds
Triglycerides: Saturated Vs.
Unsaturated
•
•
Saturated = single bonds ONLY in carbon
chain = BAD FATS….will clog up vessels
– Carbons “saturated” w/ hydrogen (solid
at room temp)
Unsaturated = double or triple bonds (liquid
at room temp)= GOOD FATS…squeeze through more easily
Saturated
Unsaturated
Steroids
•
Lipids that form into 4 rings
– Many are hormones
–Cholesterol, testosterone
Nucleic Acids =
#4 (DNA, RNA)
•
•
•
•
Nitrogenous base + sugar
+ phosphate molecule
Store hereditary info.
Form the code of life
Monomer = nucleotide
–sugar, phosphate, base
° L-Shaped
Tests
Organic
Reagent
compound
Positive
result
Simple sugar
Benedicts
Solution
Starch
Iodine
Any color
change but
blue
Purple/Black
Protein
Biuret
Purple
Lipid
Brown Paper
Translucent
Activation Energy= Ch 3
•
Energy needed by molecules in
order to react
–Energy needed to start a
chemical rxn
Enzymes
Enzymes
•
•
Reduce amount of activation energy
Are biological catalysts in living things
speed up chem rxns:
– are proteins
– Specific shape
– Active site:
crevice where substrate
binds to enzyme during
a reaction
Enzymes
•
Need a specific
–Temperature
–pH
•
Concentration of enzyme & substrate and
ionic conditions are important
Are NOT consumed in rxn…are recyclable
Is lock and key model or induced fit (into
active site)
•
•