Download CHAPTER 6sThe Chemistry of Life2015

CHAPTER 6 The Chemistry of Life
Main Ideas:
1. Matter is composed of tiny particles called atoms.
2. Chemical reactions allow living things to grow, develop, reproduce, and adapt.
3. The properties of water make it well suited to help maintain homeostasis in an
organism.
4. Organisms are made up of carbon-based molecules.
I. Basis of Life
A. matter
1.
a. can be a solid/liquid/gas
B. matter
1. atoms
a.
C. molecules2/more atoms bonded together
D. element
1. imp b/c elements are essential for life
a.
b. other 1%=trace elements
c. carbon is imp b/c it bonds easily with other elements
II. ATOMIC STRUCTURE
A. What is the structure of an atom?
1.
2. The nucleus is the center of the atom & it determines the chemical ID of an atom
3.
4.
5.
a. most atoms have outer orbitals/shells that are not completely full
b.
6. atoms contain the same number of electrons & protons no net chargeneutral
7. atoms are the basic building blocks of all matter
B. How are elements identified?
1. By letter symbols on the periodic table Na=sodium, H=hydrogen
2. the periodic table contains the atomic number & the atomic mass
a. atomic number=
b. atomic mass=
3. their structure determines their properties & chemical behavior
4. isotopes
a.
1. isotopes can be used in radiometric dating b/c as an isotope decays/breaks down it
releases what is known as a daughter element
2. the isotope is known as a parent element
3. when carbon 14 decays, it decays into nitrogen 14
4. carbon 14 has a half-life of 5,730 years
5. half-life
6. using the ratio of parent elements to daughter elements present & the known halflife, scientists can determine the age of a rock/fossil
III. CHEMICAL BONDS & MOLECULES
A.
1.
a. compounds have unique characteristics
b. always form from a specific combination of elements in fixed ratio
c.
B. Chemical Bonds & Lewis Dot Structures
1. the atoms in a compound are held together by chemical bonds
2. where are electrons found?
a. remember electrons exist in orbitals/energy levels?
b.
c.
d.
e.
f.
3. Covalent bonds
a.
b. example of 2 hydrogen atoms sharing electrons & H2O
c. found in most living organisms
d. molecule
4. Ionic Bonds
a.
b.
1. cation
2. anion
c. some atoms combine when they gain/lose electrons
d.
e. NaCl
f. ionic compounds are essentialnerve impulses, homeostasis, & muscle contractions
g. include: sodium (Na), potassium (K), calcium (Ca), chloride (Cl), carbonate (CO32-)
5. van der Waals Forces
a. ever wonder how water can stay above a the rim of a glass?
b.
1.
2. van der Waals Forces
c. found in waterallows H20 to form droplets
d. how are van der Waals Forces diff from covalent/ionic bonds?
6. Lewis Dot Structures
III. CHEMICAL REACTIONS
The process by which atoms/grps of atoms in substances are reorganized into diff.
substances
A. Reactants & Products
1. every second there are chemical rxns occurring in our bodies
2.
3. chemical rxns involve the reactants
a.
b.
B. Energy of Reactions
1. for reactants to form products energy is req
2. activation energy
a. activation energy is diff for every rxn
3. energy changes during chemical rnxs
a. exothermic
b. endothermic
C. Enzymes
1.
2. catalyst
a. w/o a catalyst the rxn can take longer or not at all
3. how an enzyme works
a. substrate
b. active/activation site
c.
1.
think lock & key
2.
3.
4. once the new products are formed, they are released by the enzyme
4. many factors affect enzymatic activitypH, temp, other enzymes
5. enzymes are involved in almost every biological process
IV. WATER & SOLUTIONS
A. Water’s Polarity
1. in a H20 molecule the electrons are more strongly attracted to the oxygen atom’s
nucleus
a.
b. polar molecules
c. polarity
d. when opp ends of polar molecules are close to ea other a weak electrostatic
attraction occurs
1. hydrogen bond
2.
3.
allows H20 to have the properties of cohesion, adhesion, & surface tension
4. cohesion
5.
adhesion
6. surface tension
B. Mixtures with Water
1. mixture
a. heterogeneous mixturethe components remain distinct
2. solution
a. 2 componentsa solvent & a solute
1. solvent
2. solute
C. Acids & Bases
1. many solutes easily dissolve in H2O
2. acid
a. the more H+ released the more acidic the solution becomes
3. base
a. the more OH- released the more basic the solution becomes
D. pH & Buffers
1. pH
a. scale is 0-14
b. pure H2O is 7neutral
2. why is the pH level imp?
a. most biological processes occur at a pH range of 6.5-7.5
b. buffers
V. THE BUILDING BLOCKS of LIFE
A. Organic Chemistry
1. carbon basedb/c carbon is essential for all life
a. carbon can easily form covalent bonds w/ other atoms & functional grps; stable
b. can form chains, branched, or ring compounds
B. Macromolecules
1.
a.
b. isomers=
c. 4 types of macromolecules:
C. Carbohydrates
1
a. simple carbohydratemonosaccharidesimple sugar5C/6Cribose & deoxyribose
b. monosaccharide + monosaccharidedisaccharidesucrose
c. polysaccharidespolymers of many monosaccharides
1. starch
2. glycogen
3. cellulose
4. chitin
D. Lipids
1.
2. hydrophobic
3. fats, oils, waxes, & steroids are lipids
4. fatty acid
a.
b.
5. phospholipids
6. steroids
7.
E. Proteins
1.
2. amino acids(AA)
a. peptide bond
b. essential for life
c. AA structure
1.
2. the variable grp(R-grp)
3.
3. structure
4. proteinsinvolved in nearly every f(x) in your body
a.
F. Nucleic acids
1. account for only 2% of the wt of animals
2.
3. nucleic acids are polymers of nucleotides
a.
b.
4. DNA
5. RNA
a.
6. adenosine triphosphate (ATP)
b.