1. Unit 2: Biochemistry
The Chemistry of Life

2. Part 1: Basics of Chemistry
Atomic Structure Reminder:
Atoms contain three subatomic particles…
1. Protons…positive charge
2. Neutrons…no charge
3. Electrons…negative charge
These are located in NUCLEUS!
Electrons surround the nucleus in orbitals

3. - Elements, Mixtures, and Compounds -
1. _______________
- a ______ substance made up of one type of atom.
- organized on ______________
- each element has a unique
number of ______…its _____________

5. Each element is described with
The atomic number is
the number of PROTONS
Each element is described with
its name and symbol

6. the number of PROTONS plus
The atomic mass is
the number of PROTONS plus
the number of NEUTRONS

7. So an atom of silicon has
how many neutrons?
28 – 14 = 14 neutrons

8. 2. Mixture - Elements, Mixtures, and Compounds -
- made up of more than one type of
substance
- physically combined
Examples: mixture of sugar and salt, salad dressing, solutions,
and your blood!

9. Examples: water (H2O), glucose (C6H12O6), and salt (NaCl)
- Elements, Mixtures, and Compounds -
3. Compound
- made up of more than one type of
substance
- chemically combined
- always combined in same RATIO… that’s the chemical formula!
Examples: water (H2O), glucose (C6H12O6), and salt (NaCl)

10. Chemical Bonding Covalent Bond two or more atoms share
electrons to form a molecule
Ionic Bond
electrons are lost/gained by
atoms and become charged

11. Part 2: Properties of Water and pH
Draw structure of five water molecules
polar
covalent bond
O and H atoms do not share electrons equally
Oxygen is slightly negative
Hydrogen atoms are slightly positive
hydrogen bond

12. Properties of Water Storage of Heat Cohesion Adhesion
Universal Solvent
All properties
due to the fact
that water
molecules
are POLAR

13. Ions
Remember that atoms that either gain or lose electrons become ions, which are charged particles
If an atom loses an electron, it becomes a positive ion called a cation
If an atom gains an electron, it becomes a negative ion called an anion

14. pH Scale Acids are substances that produce hydrogen ions in solution
In solutions, water molecules can split into hydrogen ions and hydroxide ions
Acids are substances that produce hydrogen ions in solution
Bases are substances that produce hydroxide ions in solution
The pH scale measures how acidic or basic a solution is, which is based on ratio of hydrogen and hydroxide ions

15. pH Scale Acidic solutions have a greater number of hydrogen ions
than hydroxide ions
Basic solutions have a greater number of hydroxide ions
than hydrogen ions

16. What does the term “organic” mean?
Macromolecules
Four categories of organic molecules
1. Carbohydrates
2. Proteins
3. Nucleic Acids
4. Lipids
In general, called macromolecules
First three categories are also polymers
What does the term “organic” mean?

17. Ex. If a sentence is a polymer,
Polymer Principles
Polymer – a long molecule consisting of similar or identical building blocks covalently linked together
Monomer – the individual building blocks that make up the polymers
Ex. If a sentence is a polymer,
words are monomers

18. Polymer Principles

19. Example: formula for glucose is C6H12O6
Carbohydrates
Commonly called sugars
Only contain the elements carbon, hydrogen, and oxygen in a specific ratio of 1:2:1
Example: formula for glucose is C6H12O6
Main Function: short-term energy source
Found in: foods like fruits, vegetables, grain

20. Carbohydrates Monomers are called monosaccharides
Ex. simple sugars like glucose
and fructose
Link two together to form a disaccharide
Ex. sucrose – common table sugar
Many linked together to form a polysaccharide
Ex. glycogen in animals
Ex. starch and cellulose
in plants

21. Proteins Also called polypeptides
Contain elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur
Monomers are called amino acids
20 different types of building blocks
Chemical properties vary based on structure of the amino acids
Proteins are assembled by RIBOSOMES

22. Shape determines protein’s functions!
Polypeptide
Amino Acid
Peptide Bond
After amino acids are linked together, the chain folds into a specific shape!
Shape determines protein’s functions!

23. Proteins Many Functions! structural proteins like collagen in skin
antibodies in your immune system
contractile proteins in your muscles
ENZYMES – help speed up chemical reactions
by reducing activation energy
A Note about Enzymes
A substrate is a molecule that an enzyme reacts with.
Enzymes and substrates fit together like a lock and key.

24. Proteins Remember the function of all proteins is based on the
shape of the protein!
If the shape of a protein changes,
the protein can no longer do its job!

25. Nucleic Acids Two types: DNA and RNA
Contain elements carbon, hydrogen, oxygen, nitrogen, and phosphorus
Monomers are called nucleotides
made up of three subunits
5-carbon sugar
nitrogen base
phosphate group

26. Nucleic Acids Nucleotide 3. 1. 2. Phosphate Group 5-Carbon Sugar
(Dexoyribose or Ribose)
3. Nitrogen Base

27. Nucleic Acids
There are 4 different nitrogen bases in DNA: Adenine, Guanine, Cytosine and Thymine
RNA uses the nitrogen base Uracil instead of Thymine
DNA carries genetic information, while RNA is used in the making of proteins 1. 2. 3.

28. Lipids Technically not a polymer
Include: fats, phospholipids, steroids,
and waxes.
Composed of a backbone glycerol and fatty acid chains
Functions:
1. Fats serves as long-term energy storage.
2. Cell membranes are made of phospholipids.
3. Many hormones are steroids.

29. Lipids Glycerol Fatty Acid Chains Phospholipid
General Structure of a Steroid