Transcript Chemistry of Life Notes (my notes).

Chemistry of Life
Chapter 2
 How
are living things (biotic) and nonliving (abiotic) things different?
 How are they the same?
 All
composed of Atoms
Element = substance that can’t be broken
down into simpler chemical
substances.
1. Represented by 1 or 2 letter code
(H, O, Na, Cl, He, Ne…)
2. Made up of atoms
Atoms = smallest particle of an element
that has characteristics of that element.
Structure of an Atom
 In
the Nucleus: mass of the atom
Protons (p+) – positive charge
Neutrons (n0) – no charge (neutral)
 In
the Electron Cloud: space of atom
Electrons (e-) – negative charge; in
constant motion revolving around nucleus
7 different energy levels; each can only
hold a set amount of electrons
IONS
 Atoms
or group of atoms with a
positive or negative charge
 Formed by loss or gain of electrons
Combination of Substances
 Mixture:
Physical combination of 2 or more things.
Each substance keeps its original properties.

Compound:
Chemical combination of 2 or more
elements.
The substances lose their original properties
and form something new.
Bonding
Combination of elements with
electrons to become more stable
Atoms want to have full outer e- level
2 e- in 1st level
8 e- in 2nd through 7th levels
 Covalent
Bonding:
Sharing of electrons between atoms
example: Water (H2O)
 Ionic
Bonding:
Transferring of electrons between atoms
Example: Table Salt (NaCl)
Chemical Reactions
 forming
or breaking of bonds between
atoms
 causes substances to combine and
recombine to form molecules or
compounds.
 Occur only when conditions are right
Metabolism = chemical reactions that
occur over and over inside our cells
Measuring Acids and Bases
chemical reactions depend on how acidic or
basic the environment is
 Indicators = pH paper, litmus, and other
substances that change color
 pH = a measure of how acidic or basic a
solution is.
 Scale from 0 to 14

0
= strongest acid (lots of Hydrogen ions)
 7 = neutral
 14 = strongest base (few hydrogen ions)
ACIDS and BASES
 Acids:
 Sour
taste (fruits)
 forms hydrogen ions (H+) in water
 abundance of H+ ions
 pH below 7, the lower the pH the
stronger the acid (Strong Acid = pH
1; Weak Acid = pH 6.9)
 ex: HCl, H2SO4, HC2H3O2 …
 Bases:
 Bitter
taste, slippery, good cleaners
 forms hydroxide ions (OH-) in water
 abundance of OH- ions
 Has a pH above 7, higher the pH
the stronger the base (Strong base
= pH 14; Weak base = pH 7.1)
 Ex: NaOH, NH3 …
Organic Molecules
 Molecules
involved in life
 HONC 1234 = rule to describe most
common organic elements and their
bonding patterns.
 H – hydrogen - 1 bond
 O – oxygen – 2 bonds
 N – Nitrogen – 3 bonds
 C – carbon – 4 bonds
Role of Carbon
in Organisms

1.
2.
3.
4.
Properties of Carbon:
Natures tinker toy
4 electrons in outer shell
Forms 4 covalent bonds to become
stable (single, double, or triple bonds)
Forms chains, branched chains, and
rings
Image of carbon skeletons
Isomers
Molecules with
same chemical
formula, but
different structural
arrangements.
 Each has different
properties
 Ex: Glucose and
Fructose (C6H12O6)

Building Blocks
 50
common building blocks to carry out
life’s functions
 Monomer – small molecule building
block of life
 Ex: glucose
 Polymer – molecule formed when
monomers are linked together
 Ex: cellulose is a polymer of glucose
Condensation
and
Hydrolysis
Reactions
Condensation Reaction
 Chemical
reaction that occurs when
monomers are linked together to form
polymers.
 Creates 1 water (H2O) molecule per
link
 Also called synthesis or dehydration
Hydrolysis Reaction
 Chemical
reaction that occurs when
polymers are broken down into
monomers
 Addition of 1 water (H2O) for each
broken link
 Occurs during digestion, decomposition
Condensation
and
Hydrolysis
Reactions
Types of Organic Molecules
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

These 4 groups of
organic molecules,
their monomers,
polymers, and
functions, are basic
and essential to
biology!
CARBOHYDRATES
(starches and sugars)


1.
2.
3.
Function – store energy for short
term; sometimes used for structural
support
Structure
Composed of C, H, and O
Ratio of 2 H for every 1 O
Monosaccharide – single sugar
1. Glucose (blood sugar), fructose (fruit
sugar)
4.
5.
Disaccharide – two sugars
1. Sucrose (table sugar – glucose +
fructose)
Polysaccharide – many sugars
1. Starch – storage in plants
(potatoes)
2. Glycogen – storage in animal
muscle and liver cells
3. Cellulose – fiber in plants (wood,
paper)
LIPIDS
(fats, oils, waxes, steroids)
Functions:
1.
2.
3.
4.
Long term energy storage
Insulation, cushioning of organs
Waterproofing (waxes)
Chemical messengers in body
(steroids)
Properties:
1.
2.
3.
Composed of C, H, and O
Much less oxygen than carbon or
hydrogen
1. Beef fat = C57H110O6
Nonpolar – no net electrical charge
1. Insoluble in water
Triglycerides = type of fat
1. Composed of 3 fatty acids
(monomers) and 1 glycerol (sugar)
2. Saturated fat = solid at room temp,
lacks double bonds between
carbons.
3. Unsaturated fat = liquid at room
temp (oils), at least 1 double bond
between carbon atoms somewhere
in fatty acid chain
Triglyceride
Steroids
1. 4 connected carbon ring structures
2. Used as chemical messengers in body
Ex: sex hormones (testosterone and
estrogen)
Phospholipids
1. Composed of 2 fatty acids, glycerol,
and a phosphate group
2. Major component of cell membrane
A Steroid
Phospholipid
PROTIENS
Functions:
1.
2.
3.
4.
5.
Structure – hair, finger nails, skin
Antibodies
Hormones
Movement – muscles
Enzymes – proteins that speed up
chemical reactions in the body
1. 10,000 types of enzymes, each has
a different function
Structure
1. Composed of C, H, O, N, and
sometimes S
2. Made of monomers called amino acids
(20 different types)
3.
Amino acids consist of central carbon
with the following attached
1.
2.
3.
4.
4.
Hydrogen
Amine group, NH2
Carboxyl group COOH
R-group – What makes the A.A. different
from the rest. (R can be one of 20 different
groups, from a simple H to a ringed
structure)
Peptide Bond = covalent bond formed
when amino acids link together to
form proteins.
Polypeptide formation
NUCLEIC ACIDS
(DNA and RNA)
Structure
1. Composed of C, H, O, N, and P
2. Monomers = nucleotides
1. Sugar – ribose or deoxyribose
2. Phosphate group
3. Nitrogen Base – A, T, G, C, and U
Function:
1. Information Storage
2. Heredity – DNA is used to pass genetic
info to next generation
3. Direct cell activities – RNA directs
synthesis of proteins
Nucleotide
Double helix
Revisiting Enzymes:
 28
days to digest food without enzymes,
only 2-4 hours with enzymes!
 Catalyst - substance that speeds up
chemical reactions w/o being consumed
by the reaction (recycled)
 substrate - molecule(s) going through
chemical reaction
 product -new molecule(s) formed after
chemical reaction
 active
site - place on enzyme where
substrate fits, like a hand in a glove.
 substrate specific - each enzyme will
only react with the substrate that fits the
active site
 denaturation - a change in the active
site so it no longer reacts with the
substrate, may be caused by extremes
in temperature, pH, or toxins
Protein denaturation