Biology notes-Chapter 2-The Chemistry of Life….

Name______

I.The nature of matter-

A. Atoms-______

  • Derived from Greek word Atomos,which means “unable to be cut”

As described by ______,2300 years ago

  • 100 million atoms would make a room about 1 cm long
  • DOES contain______particles that are smaller than an atom

Particle / Size / Location / Charge
electron / 1/1840th of mass of a proton(amu) / Energy levels in an electron cloud
proton / 1 amu / +
neutron / 1 amu / nucleus
  • Calculating subatomic particles:

PROTONS=Atomic Number=electrons(in a neutral atom)

MASS NUMBER=p + n

N=Mass-p

Electrons=p=atomic number

  • Since atoms tend to have p=electrons ,the + and – charge balance,making them neutral
  • ______center of atom bound by STRONG FORCES.
  • Electrons are attracted to + nucleus ,but are held in levels by the energy of their motion

B. Elements and Isotopes

  • ______=PURE SUBSTANCE CONSISTING OF ONE KIND OF ATOM
  • More than 100 in existence but ~24 compose living things
  • Represented by 1 or 2 letter symbol
  • Common symbols:

Name / symbol / Name / symbol
Hydrogen / Chlorine
Helium / Potassium
Lithium / Calcium
Boron / Arsenic
Carbon / Bromine
Nitrogen / Radon
Oxygen / Silver
Fluorine / Gold
Neon / Mercury
sodium / Tin
Magnesium / Iodine
Aluminum / Barium
Silicon / Radium
Phosphorus / Uranium
  • Isotopes-atoms of the same element with a different number of neutrons----example:C-12,C-13,C-14----all averaged together for the atomic mass
  • Isotopes are identified by ______.
  • Radioactive Isotopes have unstable nuclei and break down at a constant rate over time…
  • Radioactive Isotopes uses:___________-
  • All isotopes of an element have the same chemical properties because they have the same # of ______-.

C. Chemical Compounds=______

  • Shown by a chemical formula
  • Physical and chemical properties for an element differ a lot when they are bound in a compound
  • What is the ratio of H:O on H2O?______
  • Physical properties:______
  • Chemical properties:______

D. Chemical Bonds hold together atoms in a compound

  1. Ionic Bonds-electrons are transferred from one to another creating an electrical,ionic charge that binds the atoms
  • Tends to happen between metals and nonmetals
  • Looking @ p.38 ,draw what happens in a NaCl bond
  1. Covalent Bonds-______
  • The moving electrons of both atoms travel in the orbits of both atoms
  • Double or triple bonds occur when 4 or 6 electrons are shared
  • ______-smallest unit of a compound
  • See drawing 2-4 on p.38 and draw the bond of H2O

E. Van der Waals Forces_intermolecular forces that result from

unequal sharing that results in tiny + or – charges in covalent bonds

  • Help hold a molecule together a little more….see example of gecko on p.39

II. Properties of water

  • Single most abundant compound in most living things
  1. The Water Molecule

______-because of an uneven distribution of electrons between O and H atoms

O side is more – pole because it has more electrons

It is ,essentially,neutral,but has a more – and more + end

Because of this polarity water molecules can attract one another

Polar charges are written in ( ) to show they are weaker than ionic charges

H bonds not strong ,but water can form______H bonds…..causing many of its properties

A single water molecule can be involved in as many as 4 H-bonds

______-attraction between molecules of the same substance…water is cohesive

______-attraction between molecules of different substances

Look @ p.41 and describe the effect of capillary action and how it is used in nature:______

B.Solutions and Suspensions

Water is often in a ______,where 2 or more elements or compounds are PHYSICALLY combined

2 types;

1)______mixture where components evenly distributed

Ions are surrounded by water molecules and evenly distributed

______-substance dissolved

______-substance that does dissolving

2)______-mixtures of water and nondissolved materials—blood cells in a suspension of water in vessels

  1. Acids,Bases and pH-

Water molecule can react to form ions.Draw reaction as shown @ bottom of p.42:

______indicates concentration of H ions in solution

Each step represents a power of 10

______-higher concentrations of H+ ions and pH <7

______-alkaline-lower H+ concentration and pH>7

______weak acids or bases that react w/ strong ones to prevent sharp pH changes

III. Carbon Compounds

In the 1800’s,chemists thought compounds created by living things –organic compounds-were much different than others

In 1838 a German chemist made the organic compound,urea ,from nonorganic ammonium cyanate…Thus principles of chemistry governing nonliving could be applied to living things

______is actually the study of almost all C-compounds-many not having anything to do w/ living things.

  1. The Chemistry of Carbon
  2. Why is carbon special?---1) It has 4 valence electrons and can make 4 bonds 2)It can bond w/ many other elements.

3)C can bond to other C’s in single,double or triple bonds

4)C can form chains and rings

methane acetylene

butadiene

benzene

isooctane

  • Forms millions of different complex structures.
  1. Macromolecules
  • “Giant molecules found in organisms “
  • Formed by ______,in which large compounds are built by joining smaller ones.
  • ______-small units –join to form ______-large molecules
  • The 4 groups of macromolecules are______

C.Carbohydrates

  • Made up of C,H and O in a ratio 1:2:1.
  • Used by organisms for energy.
  • Used for structure.
  • Break down of sugars,like glucose(C6H12O6)provides immediate energy

sucrose

  • Starches are complex carbohydrates
  • Single sugars are called ______,like glucose,galactose and fructose.
  • ______are large molecules formed from monosaccharides

-such as glycogen or animal starch—glycogen from the liver helps out when glucose levels run low.This is also stored in muscles for energy.

  • Plants have plant starch and cellulose,which gives plants their structure----major component of wood and paper.

D. Lipids

  • Large ,varied group of macromolecules that are generally are ______in water
  • Made mostly of C,H and O
  • Groups are ______.
  • Can be used to store energy
  • Some are parts of biological membranes or waterproof coverings
  • Many are formed when glycerol is combined w/ fatty acids

1)If each C atom is joined to another C atom by a single bond it is called ______.This is because it has the max # of H-atoms.These are______.

2)If there is at least 1 C-C double bond ,it is called ______.These are ______@ room temp.example-olive oil

  • If there is more than 1 C-C double bond,it is______examples:oils such as corn,sesame,canola and peanut
  1. ______=macromolecules containing C,H,O,N and P

  • Polymers assembled from monomers called______, which contain 3 parts:
  • 5-C sugar
  • phosphate group
  • nitrogenous base
  • Nucleic Acids store and transmit ______or genetic info…2 types of nucleic acids
  1. ______-,involved in protein synthesis and has the sugar______.

RNA

  1. ______-contains genetic code and has the sugar ______.

DNA

  1. ______=macromolecules containing C,H,O and N and composed of amino acids
  • ______are compounds w/ an amino group(-NH2) on one end and a carboxyl group(-COOH) on the other end.
  • Look @ Fig 2-16 on p. 47

basic amino acid formula

  • More than 20 amino acids in nature
  • All amino acids alike in region where they may be joined by covalent bond.Thus any amino acid can be joined to any amino acid-by bonding an amino group to a carboxyl group
  • The portion of each amino acid that is different is the side chain called a ____group.Some of these R groups are acidic and some are basic…some polar and some nonploar.Some have C rings .
  • The instructions for assembling amino acids into different proteins is stored in____.

  • Each protein has a specific role….various functions include:
  • control ______rates.
  • regulate cell processes .
  • forming bones and muscles
  • transporting substances into and out of cells
  • fighting diseases
  • up to 4 levels of organization

1st –sequence of amino acids in a protein chain

2nd–amino acids within a chain can be twisted or folded

3rd –chain itself is folded—If there is more than one chain,each chain has a specific arrangement in space.

4th –Van der Waals forces and H-bonds help maintain a protein’s shape.

  1. Chemical Reactions and Enzymes
  1. Chemical reactions=______
  2. Some are fast and some are slow
  3. The elements entering into the reaction are ______and that which is produced are the ______.

Co2 + H2OH2CO3 reaction that allows release of CO2 from the bloodstream

The above reaction is reversed in the lungs.

  • Chemical reactions always involve the breaking of bonds in ______and the formation of new bonds in ______.

B. Energy in Reactions

  • Energy is released or absorbed in chemical reactions.
  • Energy Changes-
  • Chemical Reactions that release energy are called ______and often occur spontaneously.

Example: 2 H2 + O2 2 H2O….energy released as heat/sometimes as light and sound

  • Chemical reactions that require energy are called______and usually doesn’t occur by itself

Example: 2 H2O 2H2 + O2 requires an electrical current

  • Organisms must have a source of energy to carry out necessary reactions.Plants get this from products of ______and animals get it from consuming plants or other animals….thus from metabolizing food
  • Activation energy-______

  1. Enzymes-______
  • A ______is a substance that speeds up the rate of a chemical reaction by lowering activation energy.
  • Enzymes speed up reactions that take place in a cell
  • ______speeds up the release of CO2 from the bloodstream.
  • Enzymes are specific to the reaction they speed up and usually named on the basis of the reaction.
  1. Enzyme Action-
  • Reactants must collide w/ sufficient energy to make ______.
  • ENZYME-SUBSTRATE COMPLEX-enzymes provide a site where reactants can be brought together to react,thus reducing energy needed for the reaction.
  • Reactants of enzyme-catalyzed reactions are called ______.
  • Substrates bind to a site on the enzyme called the ______.These are complementary shapes..These are bound together by intermolecular forces making an______These are bound together until the reaction is done.
  • REGULATION OF ENZYME ACTIVITY
  • Affected by many variables,such as temperature
  • Cells can regulate enzymes in many ways—often w/ a protein that turns the key enzymes on and off.

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