Biology notes-Chapter 2-The Chemistry of viewBreak down of sugars,like glucose(C6H12O6)provides immediate energy for cell activities sucrose Starches are complex carbohydrates-stores extra energy Single sugars are called _____,like glucose ...

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Biology notes-Chapter 2-The Chemistry of Life

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


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






1/1840th of mass of a proton(amu)

Energy levels in an electron cloud


1 amu



1 amu


· Calculating subatomic particles:

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



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


· More than 100 in existence but ~24 compose living things

· Represented by 1 or 2 letter symbol

· Common symbols:

































· 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 ______________-.

· ‘WEIGHTED MASS”-ie .Atomic weight=average mass of all isotopes for an element


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.37 ,draw what happens in a NaCl bond

2. 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.37 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.38

· Rapid movement of electrons can create regions of tiny (+) and (-) charges/As some molecules are close together,slight attraction between oppositely charged regions of nearby molecule-esp. when molecule is large

II. Properties of water

· Single most abundant compound in most living things

A. 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/bonding with itself O,N, and F

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

· __________________-attraction between molecules of the same substance…water is cohesive-example-surface tension allows spiders to walk on water

· ___________________-attraction between molecules of different substances-example-water creating meniscus as attaches to sides of graduated cylinder

· H20 bonding in H2O is Unique orientation that enables expanding as freezes

· HEAT CAPACITY---because of H-bonds ,takes a lot of heat to get water molecules moving faster, creating high heat capacity….helping organisms maintain body temp’s

· Look @ ppt 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 non dissolved materials—blood cells in a suspension of water in vessels

B. 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-example-pH of 5 has 10 x as many H+ ions as same qty of ph 6

· ______________-higher concentrations of H+ ions and pH 7

· ________________weak acids or bases that react w/ strong ones to prevent sharp pH changes

· Buffers are dissolved in life’s fluids ,playing an important role in maintaining homeostasis in organisms

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.

A. The Chemistry of Carbon

· Why is carbon special?---1) It has 4 valence electrons and can make 4 bonds 2)It can bond w/ many other elements. Includes H,O,P,S,N to make molecules of life

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

4)C can form chains and rings

methane acetylene




· Forms millions of different complex structures.

B. 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 ,uaually, a ratio 1:2:1.

· Used by organisms for energy-main source.

· Used for structure-by plants and some animals.

· Break down of sugars,like glucose(C6H12O6)provides immediate energy for cell activities


· Starches are complex carbohydrates-stores extra energy

· Single sugars are called ______________________,like glucose,galactose and fructose.

· Sucrose=disaccharide-made of 2 sugars(notice structure in picture)

· ______________________________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

· Includes fats ,oils,waxes

· 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

· Monomer basically glycerol and fatty acids….see analyzing data,p.48

E. ____________________=macromolecules containing C,H,O,N and P

· Polymers assembled from monomers called_________________________________, which contain 3 parts:

1. 5-C sugar

2. phosphate group

3. nitrogenous base

· Nucleic Acids store and transmit ______________or genetic info…2 types of nucleic acids

1. __________________________________-,involved in protein synthesis and has the sugar_________________.

2. Single strand


3. ___________________________________-contains genetic code and has the sugar ____________________________.


· Double helix

· Contains deoxyribose

· For heredity

F. _________=macromolecules containing C,H,O and N and composed of amino acids (monomer)

· _______________________ are compounds w/ an amino group(-NH2) on one end and a carboxyl group(-COOH) on the other end.

· Look @ Fig 2-17 on p. 48

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:

1. control _____________rates(enzymes).

2. regulate cell processes .

3. forming bones and muscles

4. transporting substances into and out of cells

5. 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.

IV. Chemical Reactions and Enzymes

A. Chemical reactions=_______________________________________________________________________________________________

· Some are fast and some are slow

· 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.

1. 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---NEEDS AN ENERGY SOURCE

· 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

2. Activation energy-____________________________________________________

B. 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.

C. Enzyme Action-

· Reactants must collide w/ sufficient energy to make _____________.

1. ENZYME-SUBSTRATE COMPLEX-enzymes provide a site where reactants can be brought together to react,thus reducing energy needed for the reaction.-made of proetein

· Reactants of enzyme-catalyzed reactions are called _____________________________.

· Enzymes themselves unchanged in a reaction

· Often end in –ase/sugars in -ose

· 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.


· Affected by many variables,such as temperature ,pH

· Cells can regulate enzymes in many ways—often w/ a protein that turns the key enzymes on and off.







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