The Chemical Context of Life Image by Riedell KEY CONCEPTS: 2.1 Matter consists of chemical elements in pure form and in combinations called compounds. 2.2 An elements properties depend on the structure of its atoms 2.3 The formation and function of molecules depend on chemical bonding between atoms 2.4 Chemical reactions make and break chemical bonds.

Click the image to play the video segment. Atomic Structure 2A Click the image to play the video segment. Video 1

What is an atom? Basic unit of matter

The center of an atom called a Nucleus

The particles found in the nucleus: Proton (+) Neutron (0)

The particle found in the energy level cloud around the nucleus: Electron (-)

What is an element? Pure substance that contains only one type of atom

Which elements make up 96% of the mass of a human? Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N)

MOLECULES CAN BE SHOWN IN DIFFERENT WAYS Water molecule: http://www.lsbu.ac.uk/water/molecule.html H2O Other Images by: Riedell

Symbol A one or two letter abbreviation is called a chemical symbol.

Atomic Number # of protons

Atomic Mass # of protons + # of neutrons

A compound Atoms of 2 or more different elements chemically joined

Covalent bonds share electrons (e-) Example Water (H2O)

Ionic bonds transfer electrons (e-) Example Table salt (sodium chloride – NaCl)

 Properties of Water

WATER is important for all living things Average person ~~ 60-70% water Babies ~~ 78% Human brain ~~ 90% Image from: http://sjr.state.fl.us/programs/outreach/pubs/irl_update/images/water_glass.jpg

Characteristics of WATER: Water is polar Water resists temperature changes Water expands when it freezes Water is cohesive – it sticks to itself Water is adhesive – it sticks to other stuff Water has surface tension – ex. A bug walks on water Water can diffuse

Water is a polar molecule Atoms in covalent bond that do not share electrons equally [has (+) & (-) ends] Typically dissolves in H2O Example of a polar molecule H2O

- + Polar Molecules electric charge Because of the location of Image from: http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookCHEM2.html Because of the location of electrons in molecules, some molecules have an _________ pattern of ____________________ More ___ on one side; More ___ on the other EX: water UNEVEN electric charge + - Bending water video More about this in Chapter 7

The same molecule can have both POLAR and NON-POLAR parts EX: PHOSPHOLIPIDS The same molecule can have both POLAR and NON-POLAR parts Polar head NON-polar tails More about this in Chapter 7 Image by Riedell

Hydrogen bond Weak bond created by a hydrogen atom attracted to oppositely charged atoms Ex: Water – 2 Hydrogens (+) + 1 Oxygen (-) = H2O

HYDROGEN BONDS positively Bonds that form between the _________ charged _____________ in one molecule and a __________ charged _________ in a nearby molecule are called _____________________ positively HYDROGEN atom negatively atom HYDROGEN BONDS EX: water molecules are held together by Hydrogen bonds Hydrogen bond animation Images from: http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookCHEM2.html

Water Resists Temperature Change Water has a high specific heat capacity, which is the amount of energy that it takes to raise the temperature of 1 gram of a substance by 1°C. In other words, it takes a lot of energy to heat water.  Which takes longer to heat up? A pot with water or a pot without water?

Water expands when frozen

Water is cohesive Cohesion is an attraction between molecules of the same substance. Because of hydrogen bonding, water is extremely cohesive

Water is adhesive Adhesion is an attraction between molecules of different substances.

Water has surface tension The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. This forms a surface "film" which makes it more difficult to move an object through the surface than to move it when it is completely submerse

Water can diffuse

“Like dissolves like” HYDROPHILIC ____________________ means “water loving” _________ groups/molecules try to _________ and touch water or ______________ molecules POLAR be near other polar Water makes a great solvent in living things because so many molecules found in living things are polar or have a charge. http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg

“Like dissolves like” HYDROPHOBIC NON-polar http://egullet.com/imgs/egci/nonstocksauce/nons1.JPG “Like dissolves like” HYDROPHOBIC _________________ means “water fearing” ___________ groups/molecules try to _________ other __________ molecules and __________ ________ molecules NON-polar be near NON-polar away from polar Oil based paints dissolve in solvents such as turpentine . . . not water.

“Like dissolves like” SOAP http://mchi.mcallenisd.org/mchi/site/hosting/ipc/ipc/ipcch23htm/ipcch23sec2.htm “Like dissolves like” SOAP ______ works because it has a _____________ that dissolves _______ and a __________ that dissolves in _____ to wash away oily dirt. NON-polar end grease Polar end water

Mixture Substances are combined, but each keeps its own properties Example Salt/ sugar, Saltwater

Solution Mixture of one or more substances (one being dissolved and the other does the dissolving)

Solute Substance being dissolved in a solution

Solvent Substance doing the dissolving in a solution Lemonade = solution (solvent= water, solute = sugar, lemon juice)

Hydrogen Ions (H+) H+ acidic More H+ = more acidic http://www.guardiantrader.com/images/ph_scale.gif The number of ____ ions determines how _______ a solution will be. H+ acidic More H+ = more acidic

pH Measure of how acidic or basic a solution is 1-6 = Acidic ; 7 = Neutral; 8-14 = Basic

Acid Below 7 ; more H+ than OH- Ex: lemon juice, milk, HCl

Neutral 7 Ex: pure water (equal amount of H+ and OH-)

Base Above 7 ; less H+ than OH- Ex: ammonia, drain-o, eggs, soap

Organic chemistry is the study of all compounds that contain bonds between carbon atoms.

_________ is the most important atom found in living things CARBON four It can join to _______ other atoms at same time chains It can form ______ or _____ so it can make lots of different kinds of molecules. rings Images from: http://www.school-for-champions.com/science/chemhydrocarbon.htm

__________ molecules are found __________ and _____________ atoms http://www.mrbigler.com/Chem1-C1/topics/vsepr/VSEPR_files/image002.gif __________ molecules are found __________ and _____________ atoms ORGANIC in living things contain CARBON http://biologyjunction.com/organic_model_project_bi.htm

The 4 types of organic compounds are Carbohydrates Lipids Proteins Nucleic Acids

Macromolecules giant molecules made up of many monomers (smaller units) joined together to form polymers

POLYMERIZATION kind of synthesis small subunits similar _________________ is a ________________ reaction in which many _____________ that are ________ join to make a bigger molecule These small units are called ______________ The big molecule they make is called a _____________ kind of synthesis small subunits similar MONOMERS POLYMER Image by RIedell

Carbohydrates Composed of the elements: C, H, and O with a ratio of 2 Hydrogens to every 1 oxygen Building blocks are: simple sugars called monosaccharides Used for: energy and storage

Types of carbohydrates 1. Simple Sugar-monosaccaride, a single sugar molecule Examples: Glucose (C6H12O6) – plants produce this during photosynthesis Fructose – found in fruit Galactose – found in milk

C6H12O6 NOTE: Glucose and Fructose are isomers Isomers = same formula but a different arrangement of elements

2. Disaccharides – two simple sugars joined by a saccharide bond Examples: Sucrose – table sugar Lactose – milk sugar Maltose – found in malted beverages (malt, beer) Forming a disaccharide: Monosaccharide + Monosaccharide  Disaccharide

3. Polysaccharide – many simple sugars joined by a saccharide bond Examples: Starch – stores glucose in roots of plants (ex: potatoes); important food source for humans Glycogen – stores glucose in liver cells in humans Cellulose – found in plant cell walls to make more rigid Chitin – found in the exoskeleton of arthropods Forming a polysaccharide Three or more monosaccharides combine to form a polysaccharide.

Lipids Composed of the elements: H, and O but contains fewer O’s than carbohydrates Building blocks are: glycerol and fatty acids Used for: used to store energy, important parts of biological membranes and waterproof coverings protection, cushion, structure, insulation, Types of lipids Fatty acids Saturated – solids at room temperature (animal fats) Unsaturated – liquids at room temperature (vegetable oil) Phospholipids – make up cell membranes

Saturated and Unsaturated

Proteins Composed of the elements: C, H, O, and N Building blocks are: polymers called amino acids held together by a peptide bond Used for:control the rate of reactions and regulate cell processes, cellular structures, transport substances into and out of cells, helps fight disease Examples of proteins: antibodies, muscles, enzymes, hair

Proteins structure and function - amino acids are joined together by covalent bonds levels of organization - amino acids are assembled using instructions found in DNA

Nucleic Acids Composed of the elements: C, H, O, N and P (Phosphorus) Building blocks are: monomers called nucleotides which are made of a Simple sugar – deoxyribose for DNA and ribose for RNA Phosphate group Nitrogen base – adenine, cytosine, guanine, and thymine for DNA and adenine, cytosine, guanine, and uracil for RNA Used for: controlling cellular activities and making proteins (genes) Examples of nucleic acids: DNA and RNA

Nucleic Acids joined by covalent bonds -store and transmit hereditary, or genetic information. EX: DNA and RNA

Enzymes Made of proteins Act as a catalyst – speeds up the rate of chemical reactions Can catabolize (breakdown) or anabolize (build up) molecules Hydrolysis (Decomposition) – a whole breaks down into its parts Dehydration Synthesis – two parts come together to make a whole

Chemical reactions can also ________ molecules apart. ______________ = kind of chemical reaction in which a molecule is broken apart by adding a________ molecule. “_____” = water “_____” = break apart break HYDROLYSIS WATER hydro lysis See an animation http://apchute.com/dehydrat/dehydrat.html

opposite HYDROLYSIS is the _________ of DEHYDRATION SYNTHESIS. Adding a water molecule breaks the bond. http://www.usd116.org/apalla/biology/unit3/notes/3notes1.htm

One way to join molecules to make a bigger molecule is by ________ a _______ molecule to make a bond. = ____________________ reaction removing WATER dehydration synthesis http://www.cengage.com/biology/discipline_content/animations/reaction_types.html See an animation http://apchute.com/dehydrat/dehydrat.html

DEHYDRATION SYNTHESIS “dehydration” “synthesis” =_____________ _____________ water loss put parts together http://io.uwinnipeg.ca/~simmons/macromol/sld003.htm http://www.usd116.org/apalla/biology/unit3/notes/3notes1.htm

A chemical equation tells what happens in a chemical reaction when molecules interact. H + 2O → H20 _______________ ________________ Molecules that react Molecules that are produced → REACTANTS PRODUCTS Image by RIedell

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

Energy in Reactions chemical reaction that release energy often occur on their own, or spontaneously - chemical reactions that absorb energy will not occur without a source of energy - activation energy – the energy needed to get a reaction started

Enzymes catalyst - a substance that speeds up the rate of a chemical reaction enzyme – a protein that acts like a biological catalyst. They speed up chemical reactions that take place in cells - lowers activation energy in a reaction

Enzyme Substrate Complex provide a site for chemical reactions to take place reducing the energy needed for the reaction reactants in these reactions are called substrate substrates bind to the active site (fit like a lock and key)