Biochemistry
Review
Atoms- the building blocks of matter
Nucleus- the center of an atom Proton-positively charged
particle in the nucleus Neutron-neutral particle in
the nucleus of the atom Electron- negatively
charged particle outside the nucleus
More Review
There are many chemical Rxn’s taking place in your body
Chemical reactions are when atoms or groups of atoms reorganize Bonds are broken and reformed during
the process
Ugh… More review
An element is a pure substance that can’t be broken down into another substance All known elements are located on the
periodic table Isotopes- same number of protons
different number of neutrons May be radioactive Carbon 12 v. Carbon 14
Still reviewing…..
Compounds- one or more elements combining to form a new substance Always found in certain ratios (H2O)
Chemically and physically different from the elements it consists of (H or O goes boom)
Can’t be broken into simpler compounds physically
Can be broken down chemically (electrical current and H2O)
You should know this….
Chemical bonds hold the elements of a compound together
Covalent bond Shared electrons STRONG BONDS Form molecules
Still on bonding…..
Ions & Ionic Bonding Atoms take or give up
electrons The resulting ion has
either a + or – charge▪ NaCl Na + Cl-
Used to transmit signals in cells
Electrolytes Held together by
electrostatic forces Disassociate in water
Energy and Rxn’s
Activation Energy- minimum amount of energy for a reaction to take place A candle won’t burn
unless the wick is lit Flame (energy)
provides activation energy
Enzymes
Enzymes are biological catalysts They lower the activation energy
needed for a reaction to proceed Most reactions in the human body need
more energy than 37 0C can provide Substrate- what the enzyme works on Active Site- part of the enzyme
perfectly matched to the substrate Like a lock and key
Many things effect enzymes Temperature- too high/low they don’t work pH – too high /low they don’t work▪ Pepsin works best at a pH of 2. Where is it in your
body?▪ What pH do most enzymes work best at?
Denature- the structure of the enzyme is permanently damaged and it will no longer work Frying an egg
Water
Water is H2O It is polar
The oxygen has a slight – charge The hydrogen has a slight + charge
Acids and Bases
Most solutes can dissolve in water Acids release H+ ions Bases release OH- ions Measured on the pH Scale
Organic Chemistry
All Biological elements contain carbon Organic molecules contain carbon
(CO2 is the exception) Carbon is special:
It can bond with 4 different elements It can bond with many different
carbons Carbon can form many shapes
Chains, branches, and rings
Biochem
Macromolecules- large organic molecules
Polymers- long chains of repeating units called monomers Held together by covalent bonds Cellulose, starch, DNA, and proteins are
all polymers
4 Major Macromolecules
Macromolecule
Function
Lipids •Stores Energy•Provides Steroids•Waterproof coatings
Proteins •Transports substances•Enzymes•Provides structural support•Provides hormones
Nucleic Acids
•Stores and communicates genetic information
Carbohydrates
•Stores Energy•Provides structural support
Carbohydrates
Carbohydrates – carbon, hydrogen, and oxygen
Monosaccharide (monomer)- simple sugars Glucose
Disaccharide- 2 simple sugars bonded Sucrose
Polysaccharide-polymers of sugars Cellulose, starch, glycogen
Lipids
Lipids are mostly made of carbon and hydrogen Monomer – fatty acids
Triglyceride-type of lipid Liquid in plants (oil) Solid in animals (butter)
Saturated vs. Unsaturated Fats
Saturated Can not bind to any
more H Solid
Unsaturated Have a double bond
and a kink liquid
Phospholipids
Amphipathic- Have a polar head Non-polar tail
Component of cell membranes
Biological Barriers
Steroids – type of lipid
Cholesterol- makes cell membranes leaky
Estrogen- female hormone
Testostone- male hormone
Structure of Proteins
Proteins are polymers of amino acids (monomer) Amino acids are made of carbon, hydrogen,
oxygen, nitrogen and sometime sulfur
Amino Acids
There are only 20 amino acids
All proteins are made out of different combinations of amino acids
Amino acids covalently bond to each other
Protein Structure
Amino acids fold into a 3-D shape α-helix β-pleated sheet
3-D shape held together by hydrogen bonding
If the shape changes the protein does not function