1. Unit 3: The Chemistry of Life
The study of matter & the changes it undergoes
Unit 3: The Chemistry of Life
Ch. 2 (pg. 30), Ch. 9 (pg ), Ch. 28 (pg )

2. What is an Element? a substance made of only one type of atom
ex. = carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur
What is an element? Element = substance that is made of only one type of atom, can’t be broken into simpler substances by ordinary chemical means Examples: lead, gold, oxygen, carbon, nitrogen, helium, etc.
What are elements made of? Elements are made of atoms

3. What are the 6 Most Abundant Elements in Biological Matter?
CHNOPS makes up 99% of mass of all living things

4. What are Atoms? the smallest part of an element
What are atoms? Atoms are the smallest part of an element that has all the element’s chemical & physical properties Examples =oxygen, carbon, nitrogen, hydrogen, silicon, gold Represented by a symbol (as well as name)
Take a pile of paper clips (all of the same size and color).
Divide the pile into two equal piles.
Divide each of the smaller piles into two equal piles.
Repeat step 3 until you are down to a pile containing only one paper clip. That one paper clip still does the job of a paper clip (i.e., hold loose papers together).
Now, take a pair of scissors and cut that one paper clip in half. Can half of the paper clip do the same job as the single paper clip?
If you do the same thing with any element, you will reach an indivisible part that has the same properties of the element, like the single paper clip. This indivisible part is called an atom.

5. What Makes Up an Atom? Subatomic particle Location charge symbol
Proton
Nucleus (center of atom)
positive p+
Neutron
neutral (no charge) n0
Electron
Orbit around nucleus (located in energy levels)
negative e-
17 p+
18 n0
Central region called the nucleus Consists of: protons, p positive charges neutrons, n0 (neutral/no charge),
Most of the mass of an atom (p = 1 amu n = 1 amu, about amu heavier than proton)
Electrons, e Negatively charged particles orbit around nucleus, Located in discrete energy levels = shells Often called electron “cloud” (outer most = valence shell) smallest part of atom amu
In its neutral state, an atom has an equal number of protons and electrons…so, it has no charge.

6. Using the Periodic Table of the Elements
# of protons 16
also # of electrons
bigger of the 2 #s
periodic table = tool used to organize info about the elements. Shows atomic number (# protons) and atomic mass (# protons + neutrons).
Atomic number: number of protons in nucleus (Because atoms are neutral: # electrons = # protons)
Determines the element & its properties Atoms of the same element always have the same atomic number
Atomic Mass: total mass of protons and neutrons within an atom’s nucleus
(bigger of the 2 numbers)
to figure out # of neutrons…
atomic mass – atomic number = neutrons
protons + neutrons

7. Electrons & Energy Levels
electrons in energy levels (“shells”) around nucleus
1st shell  up to 2 electrons
other shells  up to 8 electrons (fill before go to next)
17 p+
18 n0 Na
As the # of electrons in atoms increases, more energy levels are needed to hold them. Each level can hold only a specific number of electrons.
1st  nd  rd  8
For Na (sodium), how many more electrons can the 3rd shell hold? Seven more
How many more electrons can the 3rd shell hold?

8. What Affects the Bonding of Atoms?
the # of outer (valence) level electrons
If outer level is:
not full, atom is unstable
will bond with electrons from other atom(s) to fill outer level
full, atom is stable
won’t bond
# of electrons in outermost (valence) shell governs bonding behavior
Some atoms already have full valence energy levels (& are stable) do not readily combine with other elements to form compounds
If not full, stability can be achieved by forming bonds with other atoms by gaining, losing, or sharing electrons.
3 main bond types: covalent ionic metallic

9. What causes a Covalent Bond?
atoms are held together by shared electrons
2+ atoms share electrons to form a compound single pair shared = single covalent bond pairs shared = double covalent bond
A water molecule is made up of two hydrogen atoms and one oxygen atom. Oxygen is in the 6th column of the periodic table so we know it has 6 electrons in its outermost shell.
To be balanced Oxygen needs to gain two electrons or lose six. Hydrogen needs to gain one electron to be balanced. Each hydrogen can form a covalent bond and share its electron.

10. What causes an Ionic Bond?
atoms are held together when they lose or gain electrons
Atoms & Bonding Interactive
held together when atoms lose or gain electrons charged atom = ion lose  positive gain  negative
opposite charges attract forming compounds (salts) Ex. NaCl (table salt)
The number of positive or negative charges on an ion is shown as a superscript after the symbol for an atom or group of atoms
Hydrogen ions (H+), Hydroxide ions (OH-) Sodium ions (Na+), Chloride ions (Cl-)

11. What are Molecules/Compounds?
combinations of two or more atoms bonded together
ex. = O2, H20, C6H12O6, NaCl, HCl
What is a molecule? Combination of 2 or more atoms are joined by a covalent bond Examples… oxygen O2, hydrogen H2, water H2O
Compounds substance with two or more atoms of different elements combined chemically; Elements combine in a fixed proportion (Can have properties unlike those of the elements from which it is made)
Examples water 2 hydrogen and 1 oxygen table salt 1 sodium and 1 chlorine sucrose

12. Biological Chemistry: Inorganic Molecules
simple structure
H20, 02, NH3, CO2
inorganic even though it contains carbon
an exception to the rule
Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

13. Biological Chemistry: Organic Molecules
contain:
carbon
& usually hydrogen
many atoms
Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

14. Biological Chemistry: Monomers & Polymers
monomer = small molecule
polymer = large molecule made of repeated monomers
Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

15. 4 major types of organic biological molecules
amino acid polypeptide (protein)
nucleotide nucleic acid (DNA & RNA)
monosaccharide polysaccharide
fatty acids & glycerol Lipid
carbohydrates
lipids (fats)
proteins
nucleic acids
Carbon has 6 electrons (4 in the valence shell), needs 4 more electrons, usually forms covalent bonds… not only can it bond w/ different elements, but can also bond w/ other carbon atoms, which explains why C-compounds can be so complex

16. Examples of Carbohydrates
sugar
cellulose
starch
major source of energy (& energy storage) in the body
Monomer = Monosaccharides All have the same empirical formula CH2O C6H12O6  glucose
Polymer = Sugars, Starches, Cellulose
Contain C,H,O in a ratio of 1:2: Ratio of H:O is 2:1 just like H2O Ex. C6H12O6

17. Functions of Carbohydrates
energy source, energy storage, support (plant cell walls)
cellulose
major source of energy (& energy storage) in the body
Monomer = Monosaccharides All have the same empirical formula CH2O C6H12O6  glucose
Polymer = Sugars, Starches, Cellulose
Contain C,H,O in a ratio of 1:2: Ratio of H:O is 2:1 just like H2O Ex. C6H12O6

18. Examples of Lipids oil fat
Building blocks (not monomers) = fatty acids & glycerol
Long-term energy storage, cell membrane, hormones, insulation, nerve transmission

19. Functions of Lipids
long-term energy storage, cell membrane, hormones, insulation, nerve transmission
Building blocks (not monomers) = fatty acids & glycerol
Long-term energy storage, cell membrane, hormones, insulation, nerve transmission

20. Examples of Proteins
Meat,/ fish/ eggs/ nuts/ beans
muscle
hormone
Amino Acids = Building blocks of (polypeptides & then) proteins
Contain: have a central carbon atom an Amino group  NH2
an Acid group  -COOH A variable group  R (one of 20 different atoms or group of atoms)
There are 20 different types of amino acids found in the natural world.
proteins make up muscle, enzymes, hormones, meats/fish/eggs/nuts/beans
Enzymes make reactions happen

21. Functions of Proteins
structure, enzymes, transport materials in & out of cells, hormones, muscle
hormone
muscle
Amino Acids = Building blocks of (polypeptides & then) proteins
Contain: have a central carbon atom an Amino group  NH2
an Acid group  -COOH A variable group  R (one of 20 different atoms or group of atoms)
There are 20 different types of amino acids found in the natural world.
proteins make up muscle, enzymes, hormones, meats/fish/eggs/nuts/beans
Enzymes make reactions happen

22. Examples of Nucleic Acids
(entire structure)
Examples of Nucleic Acids
Monomers = nucleotides made of sugar-phosphate backbone & 1 of 4 nitrogenous bases (In DNA… Adenine, Thymine, Cytosine, Guanine & in RNA… Uracil instead of Thymine)
Polymers = nucleic acids (DNA & RNA)
DNA = Deoxyribonucleic Acid
Stores info for putting amino acids together to make proteins
The basis of genes & heredity
RNA = Ribonucleic Acid
Helps to build proteins
Why do living things need DNA? so they can pass on genetic code & continue the species

23. Functions of Nucleic Acids
DNA
genetic “blueprint”
RNA
helps to build (synthesize) proteins
Monomers = nucleotides made of sugar-phosphate backbone & 1 of 4 nitrogenous bases (In DNA… Adenine, Thymine, Cytosine, Guanine & in RNA… Uracil instead of Thymine)
Polymers = nucleic acids (DNA & RNA)
DNA = Deoxyribonucleic Acid
Stores info for putting amino acids together to make proteins
The basis of genes & heredity
RNA = Ribonucleic Acid
Helps to build proteins
Why do living things need DNA? so they can pass on genetic code & continue the species

24. Organic Biological Macromolecules
Elements Contained
Monomer
(building blocks)
Polymer
Function
Carbohydrates
(sugars, starches, cellulose)
C, H, O
monosaccharide
(simple sugars such as glucose)
polysaccharide (such as starch & cellulose)
Energy source, energy storage, plant cell walls
Lipids
(fats, oils, & waxes)
Fatty acids &
Glycerol
(2 types of simple molecules… NOT monomers.)
Not applicable
Long-term energy storage, cell membrane, hormones, insulation, nerve transmission
Protein
(muscle, enzymes, hormones, meats/fish/eggs/ nuts/beans)
C, H, O, N, S
Amino acids
(20 different A.A.)
Polypeptides
Structure, enzymes, transport materials in & out of cells, hormones, muscle
Nucleic Acids
(DNA & RNA)
C, H, O, N, P
Nucleotides
(sugar-phosphate backbone & nitrogenous bases)
Polynucleotide (Nucleic Acids)
Carries genetic code (“blueprint for organism”) & directs protein synthesis
A monomer is a molecule that is able to bond in long chains.
Polymer means many monomers. Sometimes polymers are also known as macromolecules or large-sized molecules. Usually, polymers are organic (but not necessarily).
Enzymes make reactions happen