Download CHAPTER 6 The Chemistry of Life

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. ATOMS and THEIR INTERACTIONS
A. What is the structure of an atom?
1.
2.
3.
4.
5.
6. atoms contain the same number of electrons & protons no net chargeneutral
7. the atom is the smallest particle of an element that has the characteristics of that
element.
8.
B. What is an element?
1.
C. Why are elements important?
1. Because everything is made of elements
D. Which elements are essential for life?
1.
2.
3. Other elements like iron are present in living things, but only in a very small amount
a. these are referred to as trace elements
E. 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=
2. their structure determines their properties & chemical behavior
3. isotopes
a.
b. isotopes can be used in radiometric dating b/c as an isotope decays/breaks down it
releases what is known as a daughter element
c. the isotope is known as a parent element
d. when carbon 14 decays, it decays into nitrogen 14
e. carbon 14 has a half-life of 5,730 years
f. half-life
g.
II. Compounds & Bonding
A. What is a compound?
1.
a. ea compound has a chemical formulaH2O & NaCl
2. compounds have unique characteristics
a. always form from a specific combination of elements in a fixed ratio
b. chemically & physically diff from the elements that comprise them
c.
d.
3. chemical bonds form to hold the atoms together
4. atoms are most stable when their outermost energy level is full of electrons
B. Chemical Bonds & Lewis Dot Structures
1. the atoms in a compound are held together by chemical bonds
2. where are electrons found?
a.
b. remember electrons exist in orbitals/energy levels?
c. ea orbital has a specific number of electrons it can hold
d. ea atom has a diff. number of orbitals based on its number of electrons
e.
f.
g.
3. Covalent bonds
a.
b. example of 2 hydrogen atoms sharing electrons & H20
c. found in most living organisms
d. molecule
4. Ionic Bonds
a. atoms tend to donate/accept electrons to become more stablewhy?
b. ion
c. some atoms combine when they gain/lose electrons
d. ionic bond
e. NaCl Na11 electrons (1 in outer shell) & Cl17 electrons (7 in outer shell)
f. ionic compounds are essentialnerve impulses, homeostasis, & muscle contractions
g. include: sodium (Na), potassium (K), calcium (Ca), chloride (Cl), carbonate (CO 32-)
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 van der Waals Forces diff from covalent/ionic bonds?
6. Lewis Dot Structures
III. CHEMICAL REACTIONS
A. Reactants & Products
1. every second there are chemical rxns occurring in our bodies
2. chemical rxns occur anytime a bond is formed or broken
3. chemical rxns involve the reactants
a.
b. ea chemical rxn must be balanced
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 the substrate is the key & the active site is the locktogether they
unlock the energy req for the rxn to take place
2.
3. it’s the enzyme-substrate complex that helps break the chemical bonds in the
reactants & form new chemical bonds in the substrates=products
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
2. solution
a. 2 componentsa solvent & a solute
1. solvent
2. solute
3. heterogeneous mixturethe components remain distinct
C. Acids & Bases
1. many solutes easily dissolve in H2O
2. acid
a.
3. base
a.
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
b. can form chains, branched, or ring compounds
B. Macromolecules
1.
a.
b. 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. if ea C only has single bond, then it is a saturated fat b/c
b. if there is a double bond present, then it is an unsaturated fat
5. phospholipids
6. steroids
7.
E. Proteins
1.
2. amino acids(AA)
a. peptide bond
b.
c. AA structure
1. has a central carbon atom that bonds w/4 other atoms/grps
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.
2. nucleic acids are polymers of nucleotides
a.
b.
1. DNA
2. RNA
a.
3. adenosine triphosphate (ATP)
a.