The Chemical Context of Life KEY CONCEPTS: Matter consists of chemical elements in pure form and in combinations called compounds. An elements properties depend on the structure of its atoms The formation and function of molecules depend on chemical bonding between atoms Chemical reactions make and break chemical bonds. 2-2 Properties of Water

Atoms are the ________________: ______________ are found ______________ ______________ ___________________ in ____________________ PROTONS (+) NEUTRONS ELECTRONS ( - ) basic unit of MATTER in NUCLEUS orbit outside nucleus energy levels 2-2 Properties of Water

Atoms differ in numbers of _______, ________,& _______ PROTONSNEUTRONSELECTRONS 2-2 Properties of Water

Atoms that have gained or lost electrons have an _____________ and are called __________ They are written with a + or – next to their symbol IONS Na + Cl - electric charge 2-2 Properties of Water

Atoms/ions important for living things Carbon - C 1.____________ 2.____________ 3.____________ 4.____________ 5.____________ 6.____________ Used to make bigger molecules Ions = electrically charged atoms 1.____________ 2.____________ 3.____________ 4.____________ 5.____________ Oxygen - O Hydrogen - H Nitrogen - N Sulfur - S Sodium – Na + Chloride – Cl - Potassium – K + Calcium – Ca ++ Phosphorus - P Hydrogen – H Properties of Water

Hydrogen Ions (H + ) The number of H+ ions determines how _______ a solution will be. More H + = more acidic acidic 2-2 Properties of Water

ATOMS CAN JOIN TOGETHER TO MAKE____________ Ex: Joining 2 HYDROGEN atoms with 1 OXYGEN atom makes one ______ molecule. WATER A Chemical Formula tells _________ of and __________ atoms are in a molecule EX: ________ H2OH2O MOLECULES what kind how many 2-2 Properties of Water

VERY, VERY LARGE MOLECULES = ____________________ MACROMOLECULES EXAMPLE: Insulin = C 254 H 377 N 65 O 76 S Properties of Water

MOLECULES CAN BE SHOWN IN DIFFERENT WAYS H2OH2O 2-2 Properties of Water

Polar Molecules Because of the location of electrons in molecules, some molecules have an uneven pattern of electric charge More ___ on one side; More ___ on the other EX: water Properties of Water

The same molecule can have both POLAR and NON-POLAR parts EX: PHOSPHOLIPIDS Polar head NON-polar tails 2-2 Properties of Water

WHAT HOLDS MOLECULES TOGETHER? Molecules are held together by the ________ between ______________ regions of nearby molecules = _____________________ van der Waals forces attractionoppositely charged 2-2 Properties of Water

Bonds that form between the _________ charged Hydrogen atom in one molecule and a __________ charged atom in a nearby molecule are called _____________________ positively HYDROGEN BONDS negatively HYDROGEN BONDS EX: water molecules are held together by Hydrogen bonds Hydrogen bond animation 2-2 Properties of Water

It can form ______ or _____ so it can make lots of different kinds of molecules. _________ is the most important atom found in living things It can join to _______ other atoms at same time CARBON four rings chains 2-2 Properties of Water

__________ molecules are found __________ and _____________ atoms ORGANIC in living things contain CARBON 2-2 Properties of Water

____________________ means “water loving” _________ groups/molecules try to _________ and touch water or ______________ molecules HYDROPHILIC “Like dissolves like” Water makes a great solvent in living things because so many molecules found in living things are polar or have a charge. be near other polar POLAR 2-2 Properties of Water

_________________ means “water fearing” ___________ groups/molecules try to _________ other __________ molecules and __________ ________ molecules HYDROPHOBIC “Like dissolves like” polar Oil based paints dissolve in solvents such as turpentine... not water. be near NON-polar away from 2-2 Properties of Water

“Like dissolves like” Soap works because it has a _____________ that dissolves grease and a __________ that dissolves in water to wash away oily dirt. NON-polar end Polar end 2-2 Properties of Water

A chemical equation tells what happens in a chemical reaction when molecules interact. NaOH + HCl → NaCl + H 2 0 _______________ Molecules that react Molecules that are produced REACTANTSPRODUCTS → 2-2 Properties of Water

Chemical reactions can _____ molecules together. Chemical reactions can ______ molecules apart. REMEMBER: ALL the chemical reactions that happen in cells = _____________ METABOLISM join break 2-2 Properties of Water

One way to join molecules to make a bigger molecule is by removing a _______ molecule to make a bond. = ____________________ reaction WATER dehydration synthesis See an animation 2-2 Properties of Water

DEHYDRATION SYNTHESIS “dehydration” “synthesis” =_____________ _____________ put parts togetherwater loss Properties of Water

POLYMERIZATION is a kind of synthesis reaction in which many small subunits that are similar join to make a bigger molecule These small units are called ______________ The big molecule they make is called a _____________ POLYMER MONOMERS 2-2 Properties of Water

EXAMPLE: Nucleotide_________ subunits (A,T,G,C) join together to make a _____ molecule DNA 2-2 Properties of Water

Chemical reactions can also break molecules apart. ______________ = kind of chemical reaction in which a molecule is broken apart by adding a________ molecule. “_____” = water “_____” = break apart HYDROLYSIS WATER hydrolysis See an animation 2-2 Properties of Water

HYDROLYSIS is the _________ of DEHYDRATION SYNTHESIS. Adding a water molecule breaks the bond. opposite 2-2 Properties of Water

ATP is the energy molecule used by all cells. Breaking a bond using hydrolysis is the way ENERGY is released. More on this is Chapters 7, 8,& Properties of Water

Living things use BOTH of these kinds of _______ (and MORE) to get the materials they need. reactions 2-2 Properties of Water

WATER is important for all living things Average person ~~ 60-70% water Babies ~~ 78% Human brain ~~ 90% 2-2 Properties of Water

WHY Water is important to cells: 1. It is __________ molecule so it can ____________ lots of different substances. 2. It can _________ lots of ______ WITHOUT changing temperature very much. (That helps with HOMEOSTASIS) 3. ____________ BONDS form between water molecules so they stick together. 4.Water is an important ___________________ in many CHEMICAL REACTIONS. POLAR DISSOLVE HYDROGEN REACTANT/PRODUCT absorbHEAT 2-2 Properties of Water