Transcript AP chemistry & organic compounds

How Matter is
Organized
•Chemical Elements
•Forms all matter
•Substances that cannot be split into simpler substances by ordinary
chemical means.
•Have letter abbreviations called chemical symbols.
•Most common elements in living things  C, H, N, O, P, S
•Trace elements are present in tiny amounts (Fe, Mn, Cu)
Structure of Atoms
• An element is a quantity of
matter composed of atoms of
the same type.
Atoms contain:
• Nucleus: protons (p+) &
neutrons (neutral charge)
• Electrons (e-) surround the
nucleus as a cloud (electron
shells are designated regions
of the cloud)
Atomic Number and Mass
Number
• Atomic number is
number of protons in
the nucleus.
• Mass number is the
sum of its protons and
neutrons.
• Isotope  atoms of
same element with
different number of
neutrons (Carbon-14
& Carbon-12)
• A hepatobiliary
iminodiacetic acid
(HIDA) sc
A hepatobiliary iminodiacetic acid (HIDA) scan
Chemical Bonds
• The atoms of a molecule are held together
by forces of attraction called chemical
bonds.
• The likelihood that an atom will form a
chemical bond with another atom depends
on the number of electrons in its outermost
shell, also called the valence shell.
• Ionic, Covalent, Hydrogen
Ionic Bonds
•When an atom loses or
gains a valence electron,
ions are formed (Figure
2.4a).
•Positively and negatively
charged ions are attracted
to one another.
Covalent Bonds
• atoms of molecules sharing
one, two, or three pairs of their
valence electrons.
– Covalent bonds are
common and are the
strongest chemical bonds
in the body.
• Covalent bonds may be
nonpolar or polar.
– In a nonpolar covalent
bond, atoms share the
electrons equally; one atom
does not attract the shared
electrons more strongly
than the other atom
Polar Covalent Bonds
• Unequal sharing of electrons between atoms.
In a water molecule, oxygen attracts the
hydrogen electrons more strongly
Hydrogen
Bonds
– are weak
intermolecular bonds;
they serve as links
between molecules.
– help determine threedimensional shape of
large molecules
– Important in giving
water its properties
essential for life
Van der Waals
interactions
• Electrons are not
always
symmetrically
distributed in
nonpolar
molecules
• Occur only when
atoms and
molecules are
very close to
each other
• Weak
Water is:
•
•
•
•
•
Where life first began
Depended on by all life
70-95% the mass of a cell
¾ of Earth’s surface
The only common substance to naturally
exist in all 3 states of matter
• Dynamic because of its polarity which
allows it to be attracted to other molecules
(esp. to other water molecules)
6 Properties of
Water
• 1. Water is a Powerful
Solvent
– Solute, Solution, Solvent
– Hydrophobic vs Hydrophilic
– Shell of hydration
• 2. Water is attractive
– Water adheres to a surface due
to 2 properties:
• Adhesion
• Cohesion
– These 2 properties allow for
capillary action.
• 3. Water has High Surface Tension
– Strong interaction of water molecules
– Water striders, whirly gigs, skipping
rocks
• 4. Water has a High Specific Heat
– High heat is required to increase the
temp. of water and a great deal of heat
must be lost in order to decrease the
temp. of water.
• 5. High Heat of Vaporization
– A great deal of energy must be
present in order to break the Hydrogen
bonds to change water from liquid to
gas
• 6. Water has a high freezing point and lower density
as a solid than a liquid
– Water’s maximum density is 4 degrees Celsius
Normal pH range of arterial
blood 7.35-7.45
Acidosis – blood pH below
7.35
*depression of synaptic
transmission in CNS
Disorientation, coma, death
Alkalosis – blood pH above
7.45
*overexcitability of CNS and
peripheral nerves
Nervousness, muscle
spasms, convulsions
and death
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Tryptophan
All living organisms require 4 types
of Organic Compounds:
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
**All contain**:
Carbon
Hydrogen
Oxygen
1. Carbohydrates
•
•
•
All carbs contain
C,H,O in a 1:2:1
ratio
Functions: Energy &
structural support
Exist as:
a. Monosaccharides
b. Disaccharides
c. polysaccharides
a. Monosaccharide
“simple sugar”
3 Forms
1. Glucose - made by plants;
source of energy
2. Fructose - found in fruits;
Sweetest!!
3. Galactose – found in milk
These are ISOMERS – same
chemical formula but
different structures.
b. Disaccharide
“double sugar”
3 Forms
1. Sucrose – Table Sugar
glucose + fructose
2. Maltose - Malt Sugar
glucose + glucose
3. Lactose – Milk Sugar
glucose + galactose
•How do monosaccharides form
disaccharides?
• Hydrolysis
• Dehydration synthesis
– Glycosidic linkage – covalent bond between 2 mono’s
c. Polysaccharide
“Many Sugars”
3 Forms – All composed of repeating
units of glucose.
1.
Glycogen – Energy storage in
animals. (Liver & Muscles)
2.
Starch - Energy storage in plants
(Roots, Stems, Leaves)
3.
Cellulose - Gives strength &
rigidity to plant cell
(Fiber  Prevents Colon Cancer)
Pectin & Carrageenan
2. Lipids
• Nonpolar / insoluble / hydrophobic
• 5 types: triglycerides, phospholipids,
steroids, waxes, glycolipids
• Fx: insulation, cushion, energy storage,
hormones, membrane structure, protection
against pathogens, repel water, water
conservation
Four Ring Structure of Steroids
Glycolipid
• 3rd Carbon in glycerol is
bound to a carb chain
instead of a phosphate
group.
• Behaves like a
phospholipid because the
carbohydrate is
hydrophilic
• Found in cell membrane
and functions in
identification of the cell
3. Proteins
• Found in: meat, eggs,
nuts, beans, tofu
• Uses in body: muscle,
hormones, enzymes,
energy, transport of
oxygen (hemoglobin),
support, hair, nails,
skin, blood clots (fibrin)
• Monomers of proteins
are amino acids
• Amino acids join
together by peptide
bond
Formation of a Dipeptide Bond
• Dipeptides formed from 2 amino acids joined by a
covalent bond called a peptide bond
– dehydration synthesis
• Polypeptides chains contain 10 to 2000 amino acids.
Copyright 2009, John Wiley &
Sons, Inc.
•
Primary Structure:
ex.: lysozome
Catalyzes hydrolysis of carbohydrates
Secondary Structure:
Alpha helix: ex. hair
stabilized by hydrogen bonds
Beta pleat
ex. silk
Tertiary
Structure:
Protein
channels
Quaternary Structure:
ex.: hemoglobin
Enzymes
• Most enzymes are
proteins; some RNA
• Speed up chemical rxn;
biological catalyst
• Shape of protein allows
it to bond to specific
molecules called
substrates, causes a
change in shape
• maltase: maltose  2 glucose
• lipase: lipids fatty acids
• protease: proteins  amino
acids
**works best under certain
temperatures
Enzymes
4. Nucleic Acids
DNA and RNA
• Huge organic molecules that
contain carbon, hydrogen,
oxygen, nitrogen, and
phosphorus.
• Deoxyribonucleic acid (DNA)
forms the genetic code inside
each cell and thereby
regulates most of the activities
that take place in our cells
throughout a lifetime.
• Ribonucleic acid (RNA) relays
instructions from the genes in
the cell’s nucleus to guide
each cell’s assembly of amino
acids into proteins by the
ribosomes.
Nucleic Acids
• Each nucleotide has three parts:
– A phosphate
– A sugar (deoxyribose for DNA
nucleotides)
– One of four nitrogenous bases
• adenine (A)
• guanine (G)
• thymine (T)
• cytosine (C)
Nucleic Acids
• There is a base-pairing rule:
– A always bonds across from T
– C always bonds across from G
• A and G, called purines, are structures
composed of two rings
• C and T are pyrimidines – singled-ringed
structures
• A purine always pairs with a pyrimidine
and vice versa
Nucleic Acids
• Because of this, if one strand of DNA is
known, the other strand can be deciphered
• If we know that one strand of DNA has the
sequence:
ATCGGCA
• The other side must be:
TAGCCGT