1. “You are what you eat”

2. Organic & Inorganic Compounds
Most organic compounds occur naturally only in living organisms or their products.
All organic compounds contain carbon. Most also contain hydrogen, and may contain either oxygen, nitrogen, or both (CHON).
Most inorganic compounds do not contain carbon (H2O, NO2, H2S)
CO2 is an inorganic carbon compound.
Pure carbon is not organic.

3. Carbon’s Unique Structure
Carbon has 6 electrons (e-):
2 in the inner shell
4 in the outer (valence) shell
Each carbon atom can form 4 bonds, which are often with other carbon atoms
This gives carbon the ability to create many different structures, such as chains and rings.

4. Chemical & Structural Formulas
The chemical formula for a compound tells us which elements it contains and how many atoms of each.
The structural formula shows us how these atoms are arranged in space.
Compound Name
Chemical Formula
Structural Formula
water
H2O O
H H
carbon dioxide
CO2
O=C=O
glucose
C6H12O6

5. Covalent Bonds
The bonds that hold the atoms together within organic compounds are covalent bonds (they share electrons).
In structural formulas, covalent bonds are indicated by lines. Each line represents 2 electrons that are being shared between atoms.
One line for a single bond (2 shared e-)
H–H
Two lines for a double bond (4 shared e-)
O=O
Three lines for a triple bond (6 shared e-)
N N

6. Isomers
Isomers are compounds with the same chemical formula but different structural formulas.
The same atoms arranged in a different way
They have different physical and chemical properties.

7. Organic Polymers
The 4 major classes of biomolecules are carbohydrates, lipids, nucleic acids, and proteins.
These are the materials from which all living things are made!

8. Carbohydrates Carbohydrate = carbon + water
Made of carbon, hydrogen, and oxygen (CHO)
– 2:1 ratio of hydrogen:oxygen (H2O)
Also called saccharides (from the Greek for sugar)
-Simple Sugars Complex Carbs
1) monosaccharides ) polysaccharides
-glucose, fructose, galactose starch
2) disaccharides glycogen
-maltose (glucose + glucose) cellulose
-sucrose (glucose + fructose)
-lactose (glucose + galatose)

9. Carbohydrates Simple sugars – monosaccharides & disaccharides
Used as a quick energy source (easy to break down)
Glucose is used as an energy source in most organisms
Fructose is a monosaccharide produced by fruits
Sucrose (common table sugar) is a disaccharide composed of one glucose molecule and one fructose molecule
Monosaccharides
Disaccharides

10. Carbohydrates Complex carbohydrates – polysaccharides
Used for energy storage and structural materials
Starch is a storage form of glucose for plants that we eat for energy
Glycogen is a short-term energy source stored in our muscles and liver (we will deplete it in about 1 day if we do not eat carbs)
Cellulose is a structural material that makes up plant cell walls and gives plants their rigid structure

11. Lipids Also composed of carbon, hydrogen, and oxygen (CHO)
Higher ratio of H to O than in carbohydrates
Lipids include fats, oils, waxes, and steroids
Grouped together because they are insoluble in water
Many functions:
Energy storage/source (fats – triglycerides)
Cell membrane structure (phospholipids, cholesterol)
Insulation of nerve cells (myelin sheath)
Steroid hormones (estrogen, testosterone, etc.)
Barrier against water (waxes)

12. Structure of Lipids
Triglycerides: built from glycerol and three fatty acids
A fatty acid is a hydrocarbon chain with a carboxyl
(-COOH) group on one end

13. Structure of Lipids
Saturated fatty acids have all single bonds between carbon atoms (they are saturated with hydrogen)
Unsaturated fatty acids have at least 1 double bond

14. Structure of Lipids Phospholipids: built from
glycerol, two fatty acids,
and one phosphate group
Cholesterol & steroids: ring structures
Crash Course

15. Nucleic Acids Found in the nuclei of our cells.
Made of units called nucleotides.
CHONP
3 parts of a nucleotide: sugar, phosphate, nitrogenous base
2 Major Nucleic Acids:
DNA = deoxyribonucleic acid
RNA = ribonucleic acid

16. DNA vs. RNA DNA RNA Sugar Bases Size Function Deoxyribose Ribose
Cytosine (C), Guanine (G), Adenine (A), Thymine (T)
Cytosine (C), Guanine (G), Adenine (A), Uracil (U)
Size
Double-stranded, millions of base pairs in one molecule
Single-stranded, hundreds to thousands of base pairs in one molecule
Function
Contains the instructions for building all of the proteins our cells need
Helps carry out DNA’s instructions and build proteins

17. DNA Is a HUGE molecule and is trapped inside the nuclei of our cells
Two chains of nucleotides held together by hydrogen bonds
A pairs with T, G pairs with C

18. RNA Much smaller than DNA, can enter & exit nucleus through pores
3 types:
Messenger RNA (mRNA)
bring DNA’s instructions into the cytoplasm
Ribosomal RNA (rRNA)
what ribosomes are made of (ribosomes are protein-building machines)
Transfer RNA (tRNA)
helps build proteins

19. Proteins Made up of units called amino acids
CHONS (not all amino acids contain sulfur)
20 different amino acids that differ in their side chains

20. Proteins
The bond that holds 2 amino acids together is called a peptide bond.
2 amino acids bonded together make a dipeptide.
A long chain of amino acids is called a polypeptide.
A protein may be composed of one or more polypeptide chain.

21. Proteins Proteins have many functions: Structure
Ex: keratin in hair & nails, collagen in skin, muscle proteins
Transporting materials into & out of cells
Ex: glucose channels are “doorways” that allow glucose to enter cells from the bloodstream
Peptide hormones
Ex: insulin is needed to activate the glucose receptors
Cell receptors
Ex: Receptors in the cell membrane recognize insulin and interpret its message!

22. Proteins
Enzymes
Ex: digestive enzymes are needed to break down the food we eat into simple particles that can be absorbed through our intestines

23. Building Biomolecules
Dehydration synthesis or condensation reaction:
two small molecules are joined together to form a larger molecule, and one molecule of water is formed in the process.
2 monosaccharides  1 disaccharide + H2O
2 amino acids  1 dipeptide + H2O
1 glycerol + 3 fatty acids  1 triglyceride + 3H2O

24. Dehydration Synthesis/Condensation
1 glycerol + 3 fatty acids  1 triglyceride + 3H2O

25. Hydrolysis Hydrolysis reaction:
water is added to break a bond, often to release 1 unit from the end of a chain.

26. Energy & Reactions Potential energy Kinetic energy
stored energy
Chemical bonds store potential energy
Kinetic energy
energy of motion
When bonds are broken, energy is released that can be used to do work inside our cells
Conservation of Energy
Energy cannot be created nor destroyed, it can only change forms

27. Activation Energy
Activation energy is the minimum energy required to get a chemical reaction started
often in the form of heat

28. Catalysts & Activation Energy
Catalysts are substances that lower the activation energy for a chemical reaction
Reusable – not changed or used up in the reaction
Speed up the rate of the chemical reaction

29. Enzymes & Activation Energy
Enzymes are biological catalysts
Significantly lower the activation energy for reactions taking place inside cells
Without enzymes, these reactions would take place too slowly to support life processes
The maximum reaction rate is reached when all of the enzyme molecules are being used

30. Enzymes & Activation Energy
Without enzyme
lactose
glucose + galactose
activation energy
without enzyme
net energy released
from splitting of
lactose
(b)
With enzyme
lactase
lactose
glucose + galactose

31. The Active Site
Enzymes work by holding molecules in exactly the right position to react with each other
The molecule(s) that an enzyme works on is called its substrate.
The substrate binds to the enzyme’s active site, which is shaped to fit the substrate molecule perfectly.
The names of enzymes usually end in –ase and match the names of their substrates
Ex: lactase is the enzyme that catalyzes the breakdown of the sugar lactose

32. The Induced Fit Model
Induced fit model - The binding of the substrate induces a change in the shape of the enzyme’s active site
The shape of the active site fits the substrate even better

33. The Induced Fit Model

34. Coenzymes
Coenzymes are non-protein molecules that are often needed to assist in enzymatic reactions
They are reusable and only needed in small amounts
Made from vitamins