pH measures how acidic or basic a solution is
The pH scale ranges from 0 – 14
◦ Less than 7.0 = ACIDIC ◦ More than 7.0 = BASIC
◦ 7.0 = Neutral (pure water)
Buffer solution: prevents changes in pH
The pH scale is logarithmic
All life molecules depend on Carbon
Carbon has 4 electrons available for bonding ◦ Can form single, double, or triple bonds
Carbon can bond with itself, or a variety of
other elements
There are 4 ORGANIC MOLECULES that are
essential for all life
◦ Carbohydrates ◦ Lipids
◦ Nucleic Acids ◦ Proteins
Monomer: simple building blocks
CARBOHYDRATES are sugars!
They are composed of the atoms:
◦ Carbon (C), Oxygen (O), and Hydrogen (H)
CARB + O + HYDRATE
The building blocks of carbohydrates are
MONOSACCHARIDES (monomer)
◦ Monosaccharide: simplest sugar
Two monosaccharides combine to form
DISACCHARIDES
Glucose + Fructose = SUCROSE (table sugar)
Milk
Many monosaccharides combine to form
POLYSACCHARIDES (polymer)
◦ Polysaccharide: repeating monosaccharides
Starch – energy storage (plants)
Potatoes, corn, crackers
Glycogen – energy storage (animals)
Cellulose – structural molecule (plant cell walls)
Corn kernels, celery, lettuce
Chitin – structural molecule (fungus cell wall & insect
Glycogen Molecule
Carbohydrates provide us with QUICK ENERGY ◦ 4 kilocalories per gram
Foods: grains, fruits, vegetables, sweets
Carbohydrate Tests:
◦ Iodine will turn blue-black color to test for starch ◦ Benedict’s solution turns red-brown in the presence
LIPIDS are fats, oils, waxes, and steroids
◦ fats, testosterone/estrogen, cholesterol, bees/ear
wax, vitamins A, D, E
Lipid structure (triglyceride):
◦ Glycerol (monomer) + 3 fatty acids (monomer) =
triglyceride (polymer)
Fatty acid
Fatty Acid
Lipid Functions:
◦ Long-term energy storage and insulation
9 kilocalories per gram
◦ Major component of the plasma membrane
Phospholipid bilayer
2 Types of Fats:
◦ Saturated Fats: BAD (dairy, meat, lard, butter) ◦ Unsaturated Fats: GOOD (nuts, avocadoes, oils)
Brown paper bag test:
◦ Greasy spot = lipids
NUCLEIC ACIDS are the molecules that make
DNA and RNA!
Nucleic acids are made of NUCLEOTIDES
(monomer)
Nucleotide Structure: ◦ Simple Sugar
◦ Phosphate Group
The function of nucleic acids is to store
genetic information in the form of a code
◦ Found in the nucleus of the cell
Nucleic acids are found in all foods because
Proteins provide structural support and carry
out chemical reactions in the body
◦ Energy storage - 4 kilocalories per gram
Proteins are made of long chains of amino
acids (monomers)
◦ Amino acids are bonded together with PEPTIDE
BONDS
Polypeptide (polymer) = chain of amino acids (protein)
Chains of amino acids will FOLD into specific
3D shapes.
Lean meat, dairy, soy, nuts, beans are high in
protein
Protein is NOT the body’s preferred energy
source.
When proteins are eaten, they are broken
down into amino acids and then used to build new proteins for the body.
ENZYMES are a type of protein that speed up
chemical reactions
◦ Enzymes control almost every chemical reaction in your
body
Enzymes can either break molecules apart or join
molecules together
◦ E.g. Break food down; assemble chains of DNA
Enzymes work by lowering the amount of energy
The molecule that an enzyme interacts with is
called a SUBSTRATE
◦ Enzyme-substrate reaction
Enzymes are very SPECIFIC in how they work
◦ Each enzyme interacts with ONE specific substrate based
on its shape
Like a lock and key or a puzzle piece
Enzymes are organic catalysts. They are
conserved (not used up) in the reaction
◦ They can be reused continuously
Enzyme – doesn’t change
Environmental factors affect enzyme function:
◦ Temperature, pH, enzyme concentration and substrate
concentration
Most enzymes have an optimal pH at which they
best function.
Moderate heat speeds up enzyme reactions
because molecules are moving faster and interact more often.
◦ Food left in room temp spoils faster than in refrigerator
If enzymes are heated too much they will
DENATURE (fall apart) and stop working
A researcher is taking measurements from a local stream and determines that the stream has a pH of 5.8. Which of the following is a conclusion the researcher could make?
a. The water in the stream is acidic b. The water in the stream is basic c. The water in the stream is neutral
d. There is not enough information to make a
Which of the following explains why carbon is the atom around which organic molecules are built?
A) carbon can make bonds with any other atom
B) carbon bonds are the strongest bonds in nature
C) carbon can bond to itself to form chains, rings, etc.
Which of the following is NOT true about carbohydrates?
A) Carbohydrates are used for quick energy
B) Carbohydrates speed up chemical reactions C) Carbohydrates are made of the elements
carbon, hydrogen and oxygen
D) The building blocks or monomers of
An organic molecule is insoluble in water and is used for insulation and long term energy storage in animal bodies. Which type of
organic molecule is being described? A) Carbohydrate
A researcher isolates an organic molecule from a cell and determines that its structure allows it to store genetic information via repeating monomer subunits known as nucleotides. Which type of organic molecule should the researcher conclude that she has isolated? A) Nucleic Acid
B) Carbohydrate C) Protein
Athletes often take supplements high in amino acids. Which organic molecule are they
targeting with these supplements? A) Carbohydrates
Which organic molecule is responsible for the structure of your body (muscles and organs) and the chemical reactions of your
metabolism?
A) Carbohydrates B) Lipids
Most chemical reactions in your body rely on the help of enzymes. Which of the following best explains how enzymes facilitate reactions?
A) Enzymes slow down reactions by increasing the amount of activation energy
B) Enzymes speed up reactions by lowering the amount of activation energy
C) Enzymes speed up reactions by increasing the activation energy
