1. BIOCHEMISTRY

2. THE ATOM
Just like cells are the basic unit of life, the ATOM is the basic unit of matter.
The atom is made up of 3 particles.
Particle
Mass (daltons)
Mass Number
Charge
PROTON 1 +
NEUTRON
NEUTRAL
ELECTRON -

3. ATOMIC MASS = 4 (PROTONS & NEUTRONS)
Sketch and label this helium atom: -
ATOMIC # = 2 (PROTONS)
ATOMIC MASS = 4 (PROTONS & NEUTRONS)
NEUTRONS + + -
PROTONS
ELECTRONS

4. Atomic Energy Levels
Numbers identify energy levels (1, 2, 3, etc.) or letters identify shells (K, L, M, etc).
Electrons have more energy the farther away they are from the nucleus.

5. Rules for filling energy levels:
The K shell holds, up to a maximum of 2.
The L shell holds, up to a maximum of 8.
(The pattern of filling higher shells becomes more complex and will not concern us.)
Any shell beyond L can hold more than 8 electrons however, it will not hold more than 8 when it is the outermost shell.

6. Atomic Number/Atomic Weight
The number of protons in an atom is called the atomic number. All atoms of the same element ALWAYS have the same atomic number.
The number of protons plus the number of neutrons in an atom is called the atomic mass or atomic weight.

7. Ions vs. Isotopes

8. Ions have a…Charge # p = atomic number
# n = atomic mass – atomic number
# e:
If overall charge is 0, #e = #p
If overall charge is +, that atom has lost an electron and is now an ion
If overall charge is -, take atom has gained an electron and is now an ion

9. ISOTOPES
Atoms of the same element that have the same number of protons but different numbers of neutrons are called Isotopes. Different isotopes of the same element will have different atomic weights.
Some isotopes are radioactive and are known as radioisotopes.
They stabilize by spontaneously emitting energy and particles.
Practical uses for radioactive isotopes:
CARBON DATING
TRACERS
KILL BACTERIA / CANCER CELLS

10. Carbon Isotopes
Which subatomic particle varies among these carbon isotopes?

11. Ions
The gain of electron(s) is called reduction and the loss of electrons is called oxidation.
Atoms that have gained or lost electrons and are no longer electrically neutral are called ions:
positive ions = cations (cat-ions)
negative ions = anions (an-ions)

12. Important bonds in Biological Molecules
Important bonds in Biological Molecules There are 2 types of chemical bonds IONIC COVALENT

13. IONIC BONDS
Occur when 1 or more electrons are TRANSFERRED from one atom to another.
When an atom loses an electron it is a POSITIVE charge.
When an atom gains an electron it is a NEGATIVE charge
These newly charged atoms are now called IONS

14. COVALENT BONDS Occur when electrons are SHARED by atoms.
These new structures that result from covalent bonds are called MOLECULES
** In general, the more chemical bonds a molecule has the more energy it contains
SHARING IS CARING!

15. MIXTURES
A mixture is a material composed of TWO OR MORE ELEMENTS OR COMPOUNDS THAT ARE PHYSICALLY MIXED
Ex: salt & pepper mixed, sugar and sand – can be easily separated

16. SOLUTION/SUSPENSIONS
Two parts:
SOLUTE – SUBSTANCE THAT IS BEING DISSOLVED (SUGAR / SALT)
SOLVENT - the substance in which the solute dissolves
Materials that do not dissolve are known as SUSPENSIONS.
Blood is the most common example of a suspension.

17. FORMULA
The chemical symbols and numbers that compose a compound ("recipe")
Structural Formula – Line drawings of the compound that shows the elements in proportion and how they are bonded
Molecular Formula – the ACTUAL formula for a compound

18. Structural formula/molecular Formula for Glucose
C6H12O6

19. Acids, Bases, Alkalis, and Buffers

20. ACIDS Acids: When the oxide of some non-metals
dissolve in water they make an acid. Acids contain an excess of H+ ions (hydrogen)
Ex: lemon juice (6), stomach acid (1.5), acid rain (4.5), normal rain (6)
Facts about Acids
Acids have a sour taste.
They are corrosive.
You eat acids daily (coffee, vinegar, soda, lemon juice, etc…)

21. Alkalis
When the oxides of some metals dissolve in water they make an alkali solution.
Alkalis react with acids and neutralise them.
Alkali facts:
They feel soapy.
They are corrosive.
Sodium hydroxide, potassium hydroxide (lye)
In the human body: fruits and vegetables exert an alkaline effect, they contain, salts of alkaline metals such as calcium, magnesium, potassium and sodium.

22. BASES
Bases: always end with -OH because of the excess of hydroxide ions (Oxygen & Hydrogen)
EX: oven cleaner, bleach, ammonia, sea water, blood, pure water
Facts about Bases
substances in aqueous solutions feel SLIPPERY to the touch and taste BITTER they also react with acids to form salts!

23. What is the difference between base and alkali?
All alkalis are bases, but not all bases are alkalis.
Group 1 metals are referred to as alkali.
Alkalis have basic properties – they are a subset of bases.
Alkali is an ionic salt, whereas bases are not necessarily so.

24. The pH scale 1 – 6 8 - 14 7 Alkalis Acids Neutral 0 - Battery acid
1- concentrated sulfuric acid
2 – lemon juice, vinegar
3 – orange juice, soda
4 – tomato juice, acid rain
5 – black coffee, bananas
6 – milk, urine
7 – pure water, blood
8 – eggs, sea water
9 – baking soda,
10 – Great Salt Lake, Milk of Magnesia
11 – Ammonia,
12 – soapy water,
13 – bleach, oven cleaner
14 – liquid drain cleaner
Neutral

25. Starting with neutrality, each change by one unit of the pH scale corresponds to a tenfold increase or decrease in H+ concentration.
(pH 3 is 10 x 10 x 10 (1000) stronger than a pH of 6)
Hydronium (H3O+) is the cation that forms from water in the presence of hydrogen ions. An acidic solute is generally the source of these hydrons.
Simply put, a hydronium ion is a water molecule with an extra hydrogen ion attached to it. 

26. Applications of Neutralisation
Insect Stings
Bee stings are acidic
and can be neutralised with
baking soda (sodium bicarbonate).
Wasp stings are alkaline and can be
neutralised with vinegar.
Indigestion: Our stomach carries around hydrochloric acid.
Too much of this leads to indigestion.
To cure indigestion, you can neutralise the excess acid with baking soda or specialised indigestion tablets.

27. What are Buffers?
A solution that resists changes in pH when acid or alkali is added.
A buffer system is a partnership between a weak acid and the base that forms when the acid dissolves in water.
In all complex, multicelled organisms, diverse buffer systems operate in the internal environment – in blood and tissue fluids.

28. The End