Chapter 6
The Chemistry of Life
Atoms & Their InteractionsOrganic compounds are molecules in which
Carbon(C) combines with other elementsAll living systems contain Carbon (C),
Oxygen (O), Hydrogen (H), and Nitrogen (N)Element - A substance that cannot be broken down
into a simpler substance - Periodic TableElements are made up of hundreds of atomsAtomssmallest particle of an element (building
blocks)
Periodic Table•The number of particles in an atom determine the element •The number of electrons in the outer ring determines how reactive it is•If all electrons are paired then they are stable and will not react Noble Gases
Atoms contain the following:1. Nucleus - center of an atom it
contains A. Proton - positively charged + B. Neutrons - no charge2. Electrons - located in a cloud around
the nucleus with a negative charge -
Bohr Model of an atomIsotopes- atoms of the same element
with different numbers of neutrons
Chemical Bonding•Free electrons, that are unpaired, are also unstable and looking to form a chemical bond•Electrons are very important to the chemical bonding process
•Chemical bonding occurs when an electron moves from one atom to another•When this happens the atom giving up the electron becomes positive and the atom gaining the electron becomes negative
Covalent bondoccurs when two atomsshare electrons to become more stable Molecule group of atoms held together by
covalent bonds and having no overall charge
The physical and chemical properties of a compound differ from the physical and chemical properties of the individual elements that compose it
CompoundSubstance that is composed of atoms of two or more different elements that are chemically combined example H2O
Ion A charged particle it has gained or loss
electronsIonic BondChemical bond formed by the attractive
forces between two ions of opposite charge NaCl
Chemical reactions - bonds formed or broken
Metabolism – all of the chemical reactions that occur within an organism
Elements combine to form compounds the elements do not have their original properties
Mixture – a combination of substances in which the individual components retain their own properties
Solutions – mixture in which one is dissolved into the other (Kool-aid)
Acids and BasespH – measure of how acidic or basic a
solution is pH scale is from 0-14Must remain very stable for biological
reactions to occurOrganisms have a tendency to remain
stable under a wide range of conditions
Acid – substances with a pH < 7 forms H+ ions Bases – substances with a pH > 7 forms OH-
ions
Water and DiffusionWater makes up 70-95% of most
organismsPolar molecule – molecule with an
unequal distribution of charge one end is positive, one is negative (attraction causes it to dissolve many ionic compounds like salt, sugar)
Hydrogen BondH+ attract the O- holds many large
molecules together, proteins, also water tension allows water to creep, plants use this to water from ground called capillary action
Characteristics of Water1. Polar Molecule – has a slight
charge2. Water resists temperature
changes – requires more heat to increase , insulator, cells exist in an aqueous environment helps maintain an optimum environment
3. Water expands when it freezes therefore ice is less dense than water and it floats
DiffusionDiffusion – net movement of particles
from an area of higher concentration to an area of lower concentration
Kinetic energy – the energy of motionBrownian motion – 1827 observed the
evidence of random motion of molecules
3 factors affect diffusion: 1. Concentration – internal factor
2 external factors which speed molecular motion are: 2. Temperature 3. Pressure
Dynamic equilibrium – concentration distributed evenly through molecules still in motion
Concentration gradient – area between the two levels of concentration
November 19, 2010
Differentiate between a mixture and a solution.
Stamp on Vocab 6.3Collect McMush Lab GradeNotes on 6.3Protein Building..
6.3 Life SubstancesCarbon © is the central element for all
living things and combines with H, O, N, S and Ph to form organic compounds
Organic compounds are essential building blocks for living things and are also a major source of energy
Carbon is able to form single, double and triple covalent bonds this gives it greater strength, diversity and energy potential
Isomers – compounds with the same chemical formula but different structures
Isomers
Polymer – large molecule formed when many smaller molecules bond together
Condensations – chemical reaction by which polymers are formed covalent bond formed when water removed
Hydrolysis – method that polymers are broken apart OH and H ions come from water to break it apart
4 Basic Carbon Containing Molecules:
1. Carbohydrates – sugars starch
2. Lipids – oils, fats3. Proteins – cell structure,
muscles, enzyme4. Nucleic Acids – hereditary or
genetic material coordinates cell activity
CarbohydratesContain only C,H,O in same proportions as
water H2OBuilding blocks are simple sugars or
monosaccharides ex: glucose, fructose C6H12O6
Glucose can change its molecules (hydrolysis) within the cell and is a major source of energy
Disaccharide – double sugar sucrose formed by the synthesis of glucose and fructose
Synthesis reactions of glucose build complex carbohydrates like starch and cellulose
Polysaccharides – largest carbohydrate molecules composed of many monosaccharide subunits
Starch is a storage compound in plants used by humans
Cellulose is part of wood and cotton and gives plant cell walls rigidity
Carbohydrates are stored as glycogen in human liver and muscle (animal starch)
Starch, cellulose and glycogen consist of thousands of glucose molecules
LipidsContain only C,H,O abut fewer O ex
C57H110O6
Building blocks fatty acids and glycerolNon polar molecule – doesn’t dissolve in
waterEssential structural part of all cellsInclude simple fats, oils, plant waxes and
cholesterolContain 2x the energy per gram of
carbohydrates
LIPIDSUnsaturated – double bondSaturated – Single bond
ProteinsContain C,H,O,N and some SBuilding blocks – amino acids there
are 20 different types =1 proteinGreen plants can synthesize amino
acids, animals cannot produce all of them
Polypeptide- Long chain of amino acids
Peptide
AminoAcids
Enzymes
Enzymes are made up of proteins and used as catalysts in specific biochemical reactions
Enzymes: Promote reactions Not used up Need only small amounts
Enzymes in Action