1. Chapter 2 Chemistry of Life
Biology Mrs. Solomon

2. Chapter 2.1 The Nature of Matter
Matter: anything that has mass and takes up space
Ex. Pineapple; Water; Air, your foot
All matter is composed of atoms
Atom basic unit of life
Made up of three subatomic particles
1. Protons (+) in nucleus
2. neutrons ( ) in the nucleus
3. Electrons (-) orbit the nucleus
Outermost electrons called valence electrons

3. Atoms Charge
An atoms charge is neutral because positive protons cancel out the negative electrons

4. Number of electrons that each orbit can hold
This is an atom
An atom has orbits
Each orbit can only hold so many electrons 18 8 2
__P
__N
**Atoms want their orbits filled to become stable

5. Atomic Number = Number of protons
In C it is 6
Atomic Mass= Number of P+N
In C it is 12.01
To find electrons just look at atomic number, it’s the same
To find the # of Neutrons do the following math:
Atomic Mass-Atomic #= neutrons
= 6.01

6. Isotopes Atom with an abnormal number of neutrons Normal Carbon
Carbon isotopes

7. Elements See periodic table for examples Gold Carbon Neon Silver
An element is a pure substance made up of only one type of atom
See periodic table for examples
Gold
Carbon
Neon
Silver

8. Compounds vs. Molecules
A molecule is formed when two or more atoms join together chemically. They can be different or the same atoms
e.g. H2
If the molecule contains at least two different elements we call it a COMPOUND.
e.g. H2O or NaCl
**All compounds are molecule but not all molecules are compounds**

9. 2.1 Cont. F. The 2 main types of chemical bonds are:
Covalent bonds – form when electrons are shared between atoms
Water is an example of two
hydrogen atoms covalently
bonding with one oxygen

10. Ionic bonds – form when electrons are transferred from one atom to another.

11. Ions
Ions-If an atom is charged we call it an ion meaning it either RECEIVED or LOST and electron
Negative ions- if the atoms gains an electrons it become more - and is called an “anion”
Positive ions- If the atoms gives up an electrons it become more + and is called a “cation”

12. 2.2 Properties of Water
A. Water molecules (H2O) has a net charge of 0, but
The oxygen end has a slight negative charge
The hydrogen end has a slight positive charge - +

13. Polar vs Nonpolar
Polar molecule have an unequal sharing of electrons. See water molecules below. Electrons spend more time near oxygen than hydrogen thus giving oxygen a positive charge
Nonpolar molecules have an equal sharing of electrons

14. Hydrogen Bond
Hydrogen Bond- weak bonds between two molecules resulting from an attraction between a H atom in one molecule and an negative atom such as oxygen in this case
H2O molecule
= Strong
= Weak

15. 2.2 Cont.
Cohesion is an attraction between molecules of the same substance H2O & H2O = droplets
Adhesion is an attraction between molecules of different substances
H2O and pine needles

16. 2.2 Cont.
C. A mixture is formed by two or more elements or compounds that are physically mixed together, but not chemically joined
E.g. salt and pepper mixed together are a mixture

17. Two types of mixtures can be made with water:
Solution – all the components are evenly spread out
Water is the solvent
The substance dissolved is the solute
Suspension – mixture of un-dissolved materials
Sand and water can mix, but eventually settles out

18. 2.2 Cont. pH scale
A water molecule can split to form a hydrogen ion (H+) and a hydroxide ion (OH–)
The pH scale indicates the concentration of H+ ions in a solution
Ranges from 0-14

19. 2.2 Cont.
Acidic solutions have higher concentrations of H+ ions than pure water
They have pH values of 7 or below
A base forms OH– ions in solution
Basic, or alkaline, solutions have lower concentrations of H+ ions than pure water
They have pH values of 7 or above
7 is neutral. It has equal amounts of H+ ions and OH- ions
Buffers are weak acids or bases used to regulate fluctuations

20. 2.3 Carbon Compounds
Carbon- in all living things. Organic chemistry is the study of compounds with bonds between carbon atoms
Organic Molecules- a macromolecule containing carbon

21. Very large molecules are called
Macromolecules
Macro means large

22. Monomers vs. Polymers Monomers- smaller molecules
Think 1 Lego
Polymers= Many monomers linked together to make a larger molecule
Think a Lego bridge

23. Macromolecules/polymers form through a process called Polymerization
In this process many monomers are joined to form the larger called polymers called macromolecules

25. CHNOPS: The most abundant elements in living organisms
Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorous
Sulfur

26. How do we stick the small molecules together?
Dehydration Synthesis
Removing of water to make monomers into a polymer. Called polymerization
Monomers
“Dehydration Synthesis”
Remove water
Polymer

27. How do we break the large molecules apart?
Hydrolysis
Monomers
Adding of water to break apart bonds in polymer to make it into individual monomers again.
Hydrolysis
Add Water
Polymer

28. There are four groups of organic compounds found in living things:

29. 2.3 Carbohydrates Carbohydrates (also known as starches and sugars)
Structure:
compounds of C, H, & O
Function:
Living things use carbohydrates as their main energy source (glucose, fructose & starch- short term)
Plants and some animals also use carbohydrates for structural purposes (cellulose- tough outer wall)

30. 2.3 Cont. Simple sugars are called monosaccharides Glucose
Fructose- in fruit
Galactose- in milk
Two simple sugars joined are called disaccharide
Maltose (G+G) found in germinating grain. Least common in nature
Sucrose- Cane sugar/ bleached table sugar (G+S)
Lactose- In milk (G+Gal)
When two or more monosaccharides join, they form a polysaccharide
e.g. Cellulose- part of cell wall
starch- form of energy storage in plants
Chitin- exoskeletons
Glycogen- form of energy storage in animals/fungi

31. 2.3 Cont. Lipids (fats, oils, waxes) – made mostly of C & O
Structure: Lipids molecules are made up of monomer compounds of fatty acids and glycerol
Function: Used to store energy; hold more than 2X sugar or protein
Found in: Forms parts of cell membranes
Waterproof coverings (phospholipids) they are hydrophobic

32. 2.3 Cont. Nucleic acids (DNA & RNA) Structure: contain H, O, N, C & P
Function:
Stores (DNA)
Transmits (RNA) hereditary, or genetic information

33. 2.3 Cont. Proteins Structure: Made of N, C, H & O
Amino acids are the monomers
Functions:
control the rate of reactions,
regulate cell processes
transport substances into or out of cells
help fight disease/immune system

34. Protein

35. 2.4 Chemical Reactions and Enzymes
A. Everything that happens in an organism is based on chemical reactions
A chemical reaction is a process that changes one set of chemicals into another set of chemicals

36. The elements or compounds that enter into the reaction are the reactant
The elements or compounds produced by the reaction are the products
6CO2 + 6H2O = C6H12O6 + 6O2
Reactants Products
Chemical reactions always involve breaking the bonds in reactants and forming new bonds in products
Chemical reaction

37. 2.4 Cont.
Every reaction needs energy to get started, called activation energy

38. 2.4 Cont. Some chemical reactions that make life possible are too slow
A catalyst is a substance that speeds up the rate of a chemical reaction. They work by lowering the activation energy
Enzymes are proteins that act as biological catalysts
They speed up reactions that take place in cells

40. Enzyme Substrate Complex
In an enzyme-catalyzed reaction, the reactants (known as substrates) bind to a site on the enzyme called an active site
The fit is so specific, like a lock and key, that only those substrates can bind with that enzyme
Enzymes are affected by pH and temperature. If the enzymes changes shape due to a fluctuations in pH or temperature we say the enzyme has denatured.

41. Metabolism Metabolism is the set of chemical reactions within cells.
The three main purposes of metabolism are:
conversion of food/fuel to energy to run cellular processes
conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates
elimination of nitrogenous wastes.
These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments.
Metabolism is usually divided into two categories:
Catabolism, the breaking down of organic matter, for example, by cellular respiration. Breaking down releases energy
Anabolism, the building up of components of cells such as proteins and nucleic acids. Building up consumes energy