Atoms Atoms are the basic unit of matter Atoms are composed of protons, neutrons and electrons These subatomic particles are charged….

Atoms make elements… Elements can’t be broken down into anything simpler. Examples: Carbon= C Sodium = Na Hydrogen= H Nitrogen= N

Subatomic particles have specific locations… Protons and the neutrons are found in the nucleus of the atom and electrons whizz around the outside of the nucleus Electrons are always moving. The atomic shell or orbital is the distance from the nucleus that the electron spins.

Valence shells… The outermost shell is called the valence shell. To be “happy” and full, the valence shell must have 8 electrons. The electrons in the outermost shell are the only ones that react with other atoms. If the valence shell is full, the atom does not react. Carbon only has four valence electrons (8 is the max) so carbon can bond with up to four other atoms.

Ions A normal atom is neutral (same number of electrons and protons) Ions have a different number of electrons than the neutral atom Sodium has only one valence electron… it would like to give that up so it can have a full outer shell. Chloride needs one electron to have a full outer shell. Sodium loses an electron and becomes Na+ Chloride becomes negative when it gains an electron… Cl-

Bonding= trying to be a happy, FULL atom Some atoms can easily lose electrons to be full Some atoms can easily gain electrons to become full

Ionic bonds A good example of an ionic bond is NaCl. Sodium really wants to lose an electron and becomes a positive ion (cation). Chloride really wants to gain an electron (high electronegativity) and becomes a negative ion (anion).

Covalent bonds If the two atoms have partially fill shells then the two atoms will probably just share the electrons. A good example of this methane

More covalent examples

Polar Covalent Bonds Polar Covalent means that two atoms share electrons but the electrons may spend a majority of their time with one particular atom. (joint custody) An example: WATER

Hydrogen Bonds The hydrogen ends of water are slightly positive because the electrons spend most of their time with oxygen. This means that the H’s are attracted to the O’s of other water molecules. The dotted lines show hydrogen bonds forming. Hydrogen bonds form in other molecules like DNA

MACROMOLECULES important to living things! _____________ Carbohydrates Lipids- fats, oils, waxes steroids Proteins Nucleic acids

Introductory Terms Macromolecule = “giant” molecule of living matter Monomer = subunits that are the building blocks of a polymer Example: Lego block Polymer = monomers linked together Example: Lego castle

Macromolecular Reactions  Dehydration Synthesis: 2 monomers become bonded to each other to make a polymer Lose water Hydrolysis: Water is used to break up polymers into monomers Using water to break bonds

Carbohydrates Structure: Functions: C:H:O in a 1:2:1 Ratio Example: C6H12O6 which is glucose Functions: Short-term energy- -Pasta dinner before the big race, game, etc. Structural Support

Lipids Structure: Functions: Made up of carbon, hydrogen, and a few oxygens Do not dissolve in water Functions: Long-term energy storage Chemical messengers (hormones) Insulation around your nerve cells and to keep you warm! Waxes (plant leaves to prevent water loss)

Lipids-Triglycerides Fats Made of glycerol and 3 fatty acids tails Connect via dehydration synthesis to make triglycerides Triglycerides are fat molecules… clogging arteries…

___________________ (lipid tails + glycerol/phosphate head) PHOSPHOLIPIDS ___________________ (lipid tails + glycerol/phosphate head) Polar head Non-polar tails

Lipids Steroids Made up of 4 interconnected rings Examples: Cholesterol Testosterone Estrogen

Proteins Most of a cell is made up of proteins Instrumental in almost everything organisms do Structure: All proteins are created from unique combinations of 20 different amino acids C,H,O,N (S) Major Functions: Structure Defense (antibodies) Enzymes- we will discuss these later!

Proteins Amino Acids Amino acids are the monomers of proteins Organic molecules possessing both carboxyl and amino groups ( get it AMINO…. ACID) 20 types of AAs that make up 1000s of different proteins AAs are linked together by peptide bonds to make polypeptides

Proteins Denaturation: When pH, salt concentration, temperature, and/or other environmental factors are altered, the protein may unravel and lose its shape Biologically inactive Structure + function

Nucleic Acids Structure Made of a chain of Nucleotides Nucleotides are made of a sugar, a phosphate and a nitrogen base Function Carries genetic material from one generation to the next Builds RNA and DNA

NUCLEOTIDES 2 SUGARS can be used: DEOXYRIBOSE for DNA RIBOSE for RNA

5 NITROGEN BASES Adenine= A Guanine= G Cytosine= C Thymine = T (only in DNA) Uracil= U (only in RNA) A,G= Purines C,T,U= pyrimidines

RNA vs. DNA RNA DNA Sugar is ribose Contains Uracil not Thymine Single stranded DNA Sugar is Deoxyribose Contains A,T, C, G Double stranded

ONE SPECIAL KIND of NUCLEOTIDE is used by cells to store and transport energy! ATP Sugar =_____________ Nitrogen base =__________ +___ PHOSPHATE groups That’s why it is called adenosine triphosphate RIBOSE ADENINE 3

When you use up energy or ATP…

ATP ADP Cycle So, ATP has three phosphates but energy is released when ATP turns to ADP by losing a phosphate Hydrolysis Cycles back and forth

Cohesion Water sticks to water (hydrogen bonds) Helps plants transport water through vessels

Adhesion Water sticks to other molecules (like the side of a glass) Also helps keep water moving up against gravity in plants.

Surface Tension Related to cohesion Molecules resist being pulled apart due to strong hydrogen bonds… form a “film”

Density Why can’t you fill a water bottle completely when you want to freeze it? What occurs to the structure of water when it freezes? Insulation for life below the surface…

pH Scale- ever heard of it? An acid is a compound that releases protons (H+) when dissolved in water A base is a compound that adds OH- when dissolves in water. We measure the these reactions on the pH scale

The pH Scale- ranges from 0-14 pH of 1 means lots of H+ ions and SUPER ACIDIC pH of 14 means lots of OH- (or low H+) and SUPER BASIC Water is neutral with a pH of 7

Enzymes are special proteins