The Chemistry of Life

Biosphere Biodivers ity Biology Organism -- includes everything that lives on Earth, and every place where those things live -- the variety, or all the different types, of life on Earth -- the scientific study of all forms of life, or all types of organisms -- any individual living thing Tidepo ol Estuary

1. Cells 2. Need for Energy -- all organisms are made up of one or more cells -- a cell is the basic unit of life -- all organisms need a source of energy for their life processes -- all the chemical reactions that build up or break down materials in an organism is metabolism

3. Respond to Environment 4. Reproduce & Develop -- all organisms react to the environment to survive -- physical factors such as temperature, light and touch are called stimuli -- member of a species have the ability to produce new individuals, reproduce -- organisms pass their genetic material through DNA

Systems -- all levels of life have systems of related parts a cell has chemicals and processes a body system has interacting organs an ecosystem has living and nonliving things that interact

Structure & Function -- structure determines function proteins with different structures perform different functions heart muscle cells have different structure and function than stomach muscle cells different species have different anatomical structures

Homeostasi s -- organisms must maintain homeostasis to survive in diverse environments -- homeostasis allows organisms to maintain constant internal conditions

Unity & Diversity -- evolution is the change in living things over time -- an inherited trait that gives an advantage to future generations is adaptation -- evolution can occur through natural selection of adaptations

Scientifc Method -- scientists make careful & systematic observations -- observations are recorded as data -- they form a hypothesis as a possible answer to a question -- scientists test their hypotheses

Problem Hypothesis Test Analysis Conclusion -- make observations -- identify the problem -- form a testable explanation -- typically an “ if…then ” statement -- test the hypothesis -- perform an experiment -- analyze data -- calculations, graphs & charts -- evaluate the results -- peer review, publication

Controlled Experiment I.V.I.V. D.V.D.V. Constants Control -- tests the effect of a single independent variable ( isolate one variable to test ) -- independent variable -- manipulated by scientist -- dependent variable -- measured response to I. V. -- variables that are kept constant - for all groups -- set aside for comparison ; doesn ’ t get the I. V.

Laws vs. Theories -- a law is a statement based on repeated observations -- doesn ’ t attempt to explain, simply describes -- ex ) law of gravitation -- a theory is a proposed explanation supported by much evidence -- can change with new evidence -- explains why -- ex ) the universal particle theory

Microscope s -- provides an enlarged image of an object light microscopes scanning electron microscopes transmission electron microscopes stoma

Imaging in Medicine -- imaging technology is vital in medicine X - ray imaging magnetic resonance imaging ( MRI ) computed tomography ( CT )

Computers & DNA -- computer models are useful when experimental procedures are not safe or ethical -- DNA & molecular genetics give rise to new studies

Why study biology ? -- help you better understand… your health environmental issues issues with biotechnology unanswered questions

Atoms -- All living things consist of atoms. smallest unit of matter that retains its chemical properties an element consist of one type of atom every atom has a nucleus and electrons protons and neutrons are found in the nucleus electrons are outside the nucleus in the electron cloud Oxygen (O) 8 protons 8 neutrons 8 electrons

Compounds -- two or more elements chemically bonded together ex ) H 2 O, CO 2 smallest unit of a compound is a molecule most compounds in living things contain carbon Water (H 2 O) O H H Carbon Dioxide (CO 2 ) + -

Ions -- ions form when an atom or group of atoms gain or lose electrons positive ions ( lose negative e -) negative ions ( gain negative e -) ionic bonds form between oppositely charged ions

Molecules -- atoms share electron pairs in covalent bonds most common bonding in living things molecules can have multiple covalent bonds Methane (CH 4 )

Water is Polar -- water is a polar molecule has (+) and (-) charged ends (+) end of one water molecule is attracted to a (-) end of an neighboring water molecule causing hydrogen bonding shaped like

Unique Properties -- hydrogen bonding causes water to have unique properties high specific heat : heats up slowly / cools down slowly high cohesion : sticks to itself high adhesion : sticks to other surfaces ( capillary action ) high surface tension : thin skin effect on the surface high melting point & boiling point Cohesion Adhesion Surface Tension High Specific Heat

Universal solvent -- many compounds dissolve in water a solution forms when one substance dissolves in another the solvent does the dissolving the solute is being dissolved another name for a solution is a homogeneous mixture “ like dissolves like ” polar solvents dissolve polar nonpolar solvents dissolve nonpolar

Acids & Bases -- compounds form acids or bases an acid releases hydrogen ions ( H + ) and has a pH less than 7 a base removes hydrogen ions ( low H + conc.) & a pH above 7 more basic   more acidic

Pure Water is Neutral -- pure water has a pH of 7

Carbon Compounds -- carbon can form bonds with up to 4 other atoms -- molecules can be straight, branched or ring -- many are made of small subunits bonded together

Carbo - hydrates ( sugars ) -- carbohydrates are made of C, H and O -- monomers are single units -- polymers are made of many units monomer

Carbo - hydrates ( sugars ) -- carbohydrates are the MAIN fuel source for the cell -- carbohydrates include sugars and starches -- monosaccharides are simple sugars -- polysaccharides include starches, cellulose and glycogen -- some carbohydrates are part of cell structure ( cellulose & starch )

-- starch is a polymer of glucose monomers that has a branched structure -- cellulose is a polymer of glucose monomers that have a straight rigid structure Carbo - hydrates ( sugars )

-- lipids are nonpolar molecules that include fats, oils and cholesterol -- contain carbon chain fatty acids -- can be a source of energy, make up cell membranes, and used to make hormones -- lipids are hydrophobic ( insoluble in water ) … ” water repelling ” Lipids ( fats ) Oil & Water

-- phospholipids make up cell membranes -- contain a polar phosphate head and nonpolar fatty acid tails Lipids ( fats )

-- saturated fatty acids : all single C - H bonds ( more calories ) -- unsaturated fatty acids : double bonds, fewer C - H bonds ( less calories ) Lipids ( fats )

-- polymers of amino acid polymers --20 different amino acids ( AA ) are used to build proteins -- AA differ in the side groups ( R ) -- linked by peptide bonds Proteins

-- proteins differ in the number and order of amino acids -- amino acids interact to give a protein its structure & function -- proteins : 1) build structure such as muscle 2) control chemical reactions in the cell 3) defend the body from disease -- NOT a good fuel source Proteins hemoglobin hyaline

-- nucleic acids are polymers of monomers called nucleotides -- nucleotides are made of a sugar, a phosphate group and a nitrogen base Nucleic Acids

-- there are two types of nucleic acids : DNA and RNA -- DNA stores genetic info -- RNA builds proteins Nucleic Acids DNA RNA

-- life depends on chemical reactions -- bonds break and form during chemical reactions -- reactants are changed during a chemical reaction -- products are made by a chemical reaction Reactants  Products Chemical Reactions

-- bond energy is the amount of energy that breaks or forms a bond -- bonds break and energy is released -- bonds form and energy is absorbed -- a reaction is at equilibrium when reactants and products form at the same rate Reactants  Products Bond Energy

-- activation energy is the amount of energy that needs to be absorbed to start a chemical reaction Activation Energy

-- exothermic reactions release more energy than they absorb -- reactants have higher bond energies than products -- energy is released Exothermic Reactions

-- endothermic reactions absorb more energy than they release -- reactants have lower bond energies than products -- energy is absorbed Endothermi cReactions

-- catalysts are substances that speed up chemical reactions 1. lowers activation energy of a chemical reaction 2. increases the rate of reaction Catalysts

-- enzymes are catalysts in living things -- needed for almost all processes -- most enzymes are proteins -- function best in a specific pH and temperature range -- changes in pH and temp can break H - bonds and disrupt function -- why maintaining homeostasis is vital Enzymes

-- enzyme structure allows only certain reactants ( substrates ) to bind to the enzyme -- substrates brought together -- bonds in substrate weakened Enzymes