Chemistry of LifeChemistry of Life

Chapters 4 & 5Chapters 4 & 5

BIOSPHERE

ECOSYSTEM

COMMUNITY

POPULATION

ORGANISM

ORGAN SYSTEMS

ORGANS

TISSUES

CELL

MOLECULE

ATOM

MATTERMATTER: MADE OUT OF : MADE OUT OF ATOMSATOMS Matter made out of the same kind Matter made out of the same kind

of atom is known as an of atom is known as an ELEMENTELEMENT There are 25 elements that are There are 25 elements that are

present in living organismspresent in living organisms The four main ones are: The four main ones are: Oxygen, Oxygen,

Nitrogen, Carbon & HydrogenNitrogen, Carbon & Hydrogen CompoundsCompounds are two or more are two or more

elements chemically combined in a elements chemically combined in a fixed ratiofixed ratio

What is an ATOM?What is an ATOM?

Generally, same number of protons as electronsGenerally, same number of protons as electrons When the number of When the number of ProtonsProtons changes, the kind changes, the kind

of atom changesof atom changes Generally, the same number of Generally, the same number of protonsprotons as as

neutronsneutrons. If number of neutrons is greater than . If number of neutrons is greater than protons, then the atom is called an protons, then the atom is called an isotopeisotope

SUBATOMIC SUBATOMIC PARTICLEPARTICLE

CHARGECHARGE MASS (in MASS (in relation to relation to other other particles)particles)

LOCATION IN LOCATION IN ATOMATOM

PROTONPROTON

NEUTRONNEUTRON

ELECTRONELECTRON

Periodic Table of Periodic Table of ElementsElements http://www.dayah.com/periodic/

Isotopes of CarbonIsotopes of Carbon

Carbon (C) Oxygen (O) Phosphorus (P) Calcium (Ca)CaOC P

4e– 6e–

5e–

2e–

8e–

8e–

8e–

2e– 2e–

2e–

2e–

6p+ 8p+ 15p+ 20p+6n 8n 16n 20n

Electrons and bondingElectrons and bonding

The number of electrons in the outer The number of electrons in the outer shell determines how an element will shell determines how an element will react with anotherreact with another

Elements want to have “full” outer Elements want to have “full” outer shellsshells

To have a full outer shell an element To have a full outer shell an element will either share or transfer electronswill either share or transfer electrons

Ionic Bonding: elements transfer Ionic Bonding: elements transfer electronselectrons

Covalent Bonding: elements share Covalent Bonding: elements share electronselectrons

Ionic BondIonic Bond

Elementary sodium reacts strongly with water, according to the following reaction mechanism:

2Na(s) + 2H2O → 2NaOH(aq) + H2(g)

A colourless solution is formed, consisting of strongly alkalic sodium hydroxide (caustic soda) and hydrogen gas. This is an exothermic reaction. Sodium metal is heated and may ignite and burn with a characteristic orange flame. Hydrogen gas released during the burning process reacts strongly with oxygen in the air.A number of sodium compounds do not react as strongly with water, but are strongly water soluble.

Read more: http://www.lenntech.com/periodic/water/sodium/sodium-and-water.htm#ixzz27MQRvclS

IonsIons

When an atom loses or gains When an atom loses or gains electron(s), the atom becomes an electron(s), the atom becomes an ionion

If it loses electrons, it becomes If it loses electrons, it becomes positively chargedpositively charged

If it gains electrons, it becomes If it gains electrons, it becomes negatively chargednegatively charged

Chemical BondsChemical Bonds

Ionic bondsIonic bonds → → TRANSFERTRANSFER of of electronselectrons

Covalent bondsCovalent bonds → → SHARINGSHARING of of electronselectrons

Chemical ReactionsChemical Reactions

In a chemical reaction the atoms of In a chemical reaction the atoms of the reactants are rearranged to form the reactants are rearranged to form the products of the reactionthe products of the reaction

REACTANTS PRODUCTSREACTANTS PRODUCTS

ENERGYENERGY

ENDOTHERMICENDOTHERMIC EXOTHERMIC EXOTHERMIC

The structure of waterThe structure of water

Why is water such a unique Why is water such a unique substance? substance?

WATER MOLECULEWATER MOLECULE

Water structureWater structure

Water PropertiesWater Properties

COHESIONCOHESION ADHESIONADHESION

Properties of Properties of waterwater

Meaning Meaning Implications of Implications of Property in Property in

NatureNature

CohesionCohesion

AdhesionAdhesion

Temperature Temperature ModerationModeration

Density of Ice Density of Ice

Universal Universal Solvent Solvent

In your group, read Water’s Life In your group, read Water’s Life Supporting Properties section in Supporting Properties section in your book (pp 82-84)your book (pp 82-84)

Each person is reading and filling Each person is reading and filling on the table the info for one or on the table the info for one or two of the propertiestwo of the properties

PropertyProperty Meaning Meaning Implications of Property Implications of Property in Naturein Nature

CohesionCohesion Water molecules stick Water molecules stick together due to H together due to H bondsbonds

Small animals may walk on Small animals may walk on waterwater

Adhesion Adhesion Water molecules stick Water molecules stick to other moleculesto other molecules

Capillary action. Capillary action.

Water pulled to top of treesWater pulled to top of trees

Temperature Moderation

Water makes it so changes in temperature do not happen quickly

Animals can gradually change their internal system with changes in water temperature

Density of Ice Density of Ice Ice is less dense than Ice is less dense than water so it floatswater so it floats

Ice insulates organisms Ice insulates organisms living beneathliving beneath

Universal Solvent Universal Solvent Many compounds Many compounds dissolve in waterdissolve in water

Dissolved compounds can Dissolved compounds can be brought to cells (via sap be brought to cells (via sap or blood) or move about or blood) or move about cell cytoplasmcell cytoplasm

pH scalepH scale

ACID compounds donate HACID compounds donate H++ ions ions to a solution (HCl)to a solution (HCl)

BASE compounds donates OHBASE compounds donates OH-- ions to a solution (NaOH)ions to a solution (NaOH)

BUFFERS cause a solution to BUFFERS cause a solution to resist changes in pHresist changes in pH

BIOMOLECULESBIOMOLECULES

What is the main chemical What is the main chemical element present in all element present in all biomolecules?biomolecules?

ORGANIC COMPOUNDS: Carbon ORGANIC COMPOUNDS: Carbon basedbased

INORGANIC COMPOUNDS: Non-INORGANIC COMPOUNDS: Non-carbon basedcarbon based

Molecules of lifeMolecules of life CarbohydratesCarbohydrates LipidsLipids ProteinsProteins Nucleic AcidsNucleic Acids

NotesNotes MonomersMonomers – smallest unit of – smallest unit of

polymerpolymer Polymer Polymer – Long chain of monomers – Long chain of monomers

linked togetherlinked together

NotesNotes

Carbohydrates:Carbohydrates: Organic Organic compound made up of sugar compound made up of sugar moleculesmolecules

MonosaccharidesMonosaccharides – one sugar unit – one sugar unit DisaccharidesDisaccharides – two sugar units – two sugar units PolysaccharidesPolysaccharides – long chains of – long chains of

sugar unitssugar units

Notes on LipidsNotes on Lipids

Lipids – Water-avoiding Lipids – Water-avoiding molecule (hydrophobic)molecule (hydrophobic)

Two types of Two types of lipidslipids::– FatsFats – Three long fatty acid – Three long fatty acid

chains attached to glycerol chains attached to glycerol molecule (saturated or molecule (saturated or unsaturated)unsaturated)

– Steroids Steroids – lipid molecule form of – lipid molecule form of four fused rings (testosterone, four fused rings (testosterone, estrogen & cholesterol)estrogen & cholesterol)

NOTES ON NUCLEIC NOTES ON NUCLEIC ACIDSACIDS

Nucleic Acid: A large molecule made up Nucleic Acid: A large molecule made up of smaller molecules called nucleotides. of smaller molecules called nucleotides.

Nucleotides: Small molecules made up of Nucleotides: Small molecules made up of a sugar, a nitrogen base, and phosphatea sugar, a nitrogen base, and phosphate

Nucleic acids are what our DNA or genetic Nucleic acids are what our DNA or genetic material is made ofmaterial is made of

With out nucleic acids our body would not With out nucleic acids our body would not have directions and could not function. have directions and could not function.

NUCLEOTIDENUCLEOTIDE

Notes on ProteinsNotes on Proteins

Proteins are made in cells by linking are made in cells by linking amino acids together to form amino acids together to form polypeptidepolypeptide chainschains

There are only 20 different amino acidsThere are only 20 different amino acids Proteins are composed of one or more Proteins are composed of one or more

polypeptide chainspolypeptide chains The order of amino acids in polypeptide The order of amino acids in polypeptide

chains, and the three-dimensional shape chains, and the three-dimensional shape of a protein molecule determines its of a protein molecule determines its functionfunction

Protein Shape The long Amino acid chain folds to

make the protein useable A proteins shape is changed by its

surroundings A protein that is outside of its

normal environment will be denatured (misshapen)

Notes on EnzymesNotes on Enzymes An enzyme is a type of proteinAn enzyme is a type of protein Each enzyme is specific to a Each enzyme is specific to a

kind of chemical reactionkind of chemical reaction Enzymes are able to speed up Enzymes are able to speed up

chemical reactions in living cells chemical reactions in living cells by lowering the activation by lowering the activation energy of the reactionenergy of the reaction

Enzymes are affected by pH and Enzymes are affected by pH and temperaturetemperature

Enzymes