Chapter 6
Chemistry in Biology
6.1: Atoms, Elements and Compounds
Matter is composed of tiny particles called atoms.
Building ____________ of matter = ____________ Composed of 3 ____________ particles: protons,
___________, and electrons Protons = __________ charge Neutrons = no charge (_____________) Electrons = ___________ charge Protons and ____________ are in the nucleus
blocks
atoms
subatomic
neutrons
positive
neutral
negative
neutrons
Electrons are negatively charged particles that are located outside the nucleus.
Chemistry in Biology
6.1 Atoms, Elements, and CompoundsChapter 6
Atomic StructureElectrons are moving around ____________
in various energy _____________Structure of the ____________ is possible
because of the ____________ of protons and ______________
Atoms have no __________ charge because the number of ___________ equals the number of _____________
nucleus
levels
atom
attraction
electrons
overall
protons
electrons
ElementElement – pure substance that
___________ be broken down into other substances by either ____________ or physical meansMade up of _______ type of atom_____ elements have been discovered;
_________ occur naturally in nature; approx. _______ are found in living organisms
cannot
chemical
one
112
92
20
The Periodic Table of Elements
Chemistry in Biology
Horizontal rows are called periods. Vertical columns are called groups.
6.1 Atoms, Elements, and CompoundsChapter 6
Periodic Table of ElementsPeriodic Table of Elements -
_____________ table of the elementsHorizontal rows = __________Vertical ___________ = groupsElements in the same _______ have similar
physical and __________ properties
organized
periods
columns
group
chemical
Isotopes Isotopes – atoms of the __________ element
with the same number of ____________ and electrons but a different number of _______ Mass _____________ identifies an isotope Mass number = _____________ + ______________ Ex. C-12 ____p ____n ____e
C-13 ____p ____n ____eC-14 ____p ____n ____e
same
protons
neutrons
number
protons neutrons
6 6 6
6 7 6
6 8 6
Isotopes
Chemistry in Biology
Atoms of the same element that have the same number of protons and electrons but have a different number of neutrons
6.1 Atoms, Elements, and CompoundsChapter 6
Isotopes (Cont.)Some isotopes are unstable because of the
______________ in neutrons and the nucleus begins to decay or ______________ giving off radiation - _________________
Many applications such as ________________ dating and treating _____________
difference
breakdown
radioisotopes
radioactive
cancer
Radioactive Isotopes
Chemistry in Biology
When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.
6.1 Atoms, Elements, and CompoundsChapter 6
Compounds Compounds – pure substance formed from the
_________________ of 2 or more different ______________ NaCl or H2O – chemical _____________ - tells you
the _____ of elements involved and the _____________ of atoms of each element
Characteristics: Always formed from _____________ combinations of
elements in a ____________ ratio Cannot be broken down by ____________ means but can
be broken down into _____________ elements by chemical means
combination
elements
formulakindsnumber
specificfixed
physicaloriginal
Chemical Bonds Chemical bonds – force that holds _________
together Electrons are _______________ directly in forming
chemical _________ 1st energy _________ holds up to ______ electrons 2nd energy _________ holds up to ______ electrons 3rd energy _________ holds up to ______ electrons 4th energy _________ holds up to ______ electrons Electrons in the ______________ energy level or
_________ are involved in bonding
atoms
involved
bonds
level 2
level 8
level 8
level 16
outermost
valence
Chemical Bonds (Cont.)An empty or _______ energy level is more
stable than a _____ filled energy level so atoms will ________ to lose or gain electrons to _________ stability
Covalent bonds – electrons are __________H2OMolecule – compound in which the ___________
are held together by ____________ bondsAtoms can share 1, ____ or 3 pairs of electrons to
form ___________, double or triple bonds
full
partially
seek
achieve
shared
atoms
covalent
2
single
Chemical Bonds
Chemistry in Biology
Covalent bonds
bond that forms when electrons are shared
A molecule is acompound in which the atoms are held together by covalent bonds.
6.1 Atoms, Elements, and CompoundsChapter 6
Ionic Bonds
Chemistry in Biology
Electrical attraction between two oppositely charged atoms or groups of atoms
6.1 Atoms, Elements, and CompoundsChapter 6
Chemical Bonds (Cont.)Ionic bonds – formed between 2
_____________ charged atoms or _______ of atoms called ions
Ions are ____________ when electrons are donated or ____________ either filling up an energy level or emptying one
Ions carry a _____________________ ions are attracted to negative
________ forming ionic bondsEx. NaCl
oppositely groups
formed
accepted
charge
Positive
ions
Chemical Bonds (Cont.)Characteristics of ____________ compounds
Tend to dissolve in ____________ ____________ at room temperature Higher _____________ points
Ions are important in the maintenance of ____________; nerve ______________ and muscle contractions
ionic
water
crystalline
melting
homeostasis impulses
van der Waals Forces van der Waals forces – attraction between
_______________ caused by areas of __________ charge Atoms shared in a ____________ bond are not
always shared ___________ and the unequal distribution of the _________ cloud around a molecule create theses _______ of unequal charge
Relatively ___________ but depend on size of ___________, its shape and ability to ___________ electrons
Responsible for the ability of the __________ to cling to smooth surfaces and water’s ability to form ______________
molecules
unequalcovalent
equallyelectron
areas
weakmolecule attract
gecko
droplets
6.2 Chemical ReactionsChemical reactions allow living things to
grow, develop, reproduce and adapt.Chemical reaction – process by which
___________ or groups of atoms in substances are ______________ into different substancesBonds are _____________, atoms
______________ and new bonds formed
atoms
reorganized
broken
rearranged
Glucose and oxygen react to form carbon dioxide and water.
Chemistry in Biology
6.2 Chemical ReactionsChapter 6
Physical vs. Chemical ChangePhysical change – ice melting; no
_____________ reaction involvedChemical change – one ___________
turning into another substance through a chemical reaction; metal _____________
chemical
substance
rusting
Chemical Equations Chemical equations
Reactants -> Products; arrow reads ____________ C6H12O6 + O2 -> CO2 + H2O C6H12O6 + _____O2 -> _____CO2 + _____H2O -
balanced Matter cannot be ____________ or destroyed so the
number of atoms of each ___________ in the reactant(s) must _________ the number of atoms of each element in the ____________________
yields
6 6 6
created
elementequal
products
Energy of ReactionEnergy is the ______ to starting a chemical
reactionActivation energy – minimum ____________
of energy needed for reactants to form ____________ in a chemical reaction
Varies for each _________________Reactions will either _________ off energy or
________ energy
key
amount
product
reaction
give
absorb
Chemistry in Biology
The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.
Energy of Reactions
6.2 Chemical ReactionsChapter 6
Energy of the Reaction (cont.)Exergonic reaction - ______________ in
which the products have less energy than the ____________
Energy is _________ off
reaction
reactants
given
Chemistry in Biology
This reaction is exothermic and released heat energy.
The energy of the product is lower than the energy of the reactants.
6.2 Chemical ReactionsChapter 6
Energy of the Reaction (Cont.)Endergonic reaction – reaction in which the
____________ have more energy than the _______________
Energy is ____________
products
reactants
absorbed
Chemistry in Biology
This reaction is endothermic and absorbed heat energy.
The energy of the products is higher than the energy of the reactants.
6.2 Chemical ReactionsChapter 6
EnzymesEnzymes – special ____________ that are
biological catalysts that work to ________ up the rate of chemical reactions
Catalyst – substance that _______________ the activation energy needed to ________ a chemical reaction
Not _______________ up in the reaction; ________________ Necessary because chemical _______________ tend to
occur too slowly because the _____________ energy is high Specific to ________ reaction
proteins
speed
lowersstart
used reusable
reactionsactivation
one
Chemistry in Biology
A catalyst is a substance that lowers the activation energy needed to start a chemical reaction.
Enzymes are biological catalysts.
It does not increase howmuch product is made and it does not get
used up in the reaction.
Enzymes
6.2 Chemical ReactionsChapter 6
Enzymes (Cont.)End in _____; name describes what it does
Ex. Amylase – speeds up the _____________ of amylose
Reactants that bind to the _______________ are called _____________
_____________ of substrates depends on the number of _____________
Specific location where the ____________ binds on an enzyme is called the __________ site
-ase
breakdown
enzyme
substrate
Number reactants
substrate
active
Enzymes (Cont.) Active site and ____________ have complementary
shapes so that only the required _____________ can activate the appropriate enzyme
Once the __________________ binds to the active site the active ________ changes shape and forms the __________________________ complex which helps chemical bonds to be broken and _______ bonds to form and then the ______________ releases the products
Changes in temperature, ________ and other factors can increase or _________________ enzyme activity
Enzymes are essential to ____________
substrate
substrate
substrate(s)site
enzyme-substratenew
enzyme
pHdecrease
life
Chemistry in Biology
The reactants that bind to the enzyme are called substrates.
The specific location where a substrate binds on an enzyme is called the active site.
6.2 Chemical ReactionsChapter 6
6.3 Water and SolutionsThe properties of water make it well-suited
to help maintain homeostasis in an organism.
Polarity Water is a ___________ molecule
Polar molecule – molecule that has an ______________ distribution of charges because electrons are shared _________________
Polarity is the property of having _____ opposite poles or _______; Ex. Magnet
Opposite ends of ___________ molecules are attracted to each other
In _________ this is called ___________ bonding – weak interactions involving a _____ atom and an atom of F, ____, or N
polar
unequal
unequally
2
ends
polar
water hydrogen
HO
Chemistry in Biology
6.3 Water and SolutionsChapter 6
Enzyme-Controlled Reactions
Properties of Water (Fig. 6.20, pg. 162)
1. Liquid water becomes ______ dense as it cools Begins at 4°C and is completed by _______ Water __________ when it freezes Ice floats in liquid ______________
2. Water is ____________ - it sticks to other _____________ by forming hydrogen bonds Makes ______________ action possible Ex. Explains a plant’s ability to move _________ up
the stems against ____________
less
0°C
expands
water
adhesive
substances
capillary
water
gravity
Properties of Water (Cont.) 3. Water is cohesive – it ___________ to itself by
hydrogen bonds Creates ____________ tension
4. Water forms _____________ Mixtures – combination of ____ or more substances in which
each substance retains its individual ___________________ and properties
Homogeneous mixture – mixture with a ____________ composition
Also called a ___________; has ____ parts Ex. Salt water
Solvent – substance in which another ____________ is dissolved; Ex. __________
Solute – substance that is ______________ in the solvent: Ex. ___________
sticks
surface
mixtures2
characteristics
uniform
solution 2
substancewater
dissolvedsalt
Properties of Water (Cont.)Heterogeneous mixture – mixture in which the
____________ remain distinctSuspension – mixture of ___________ and
nondissolved ________________; particles will ___________ to the bottom; Ex. Sand and water
Colloid – mixture in which the ___________ do not settle out; Ex. ________
components
water
solutes
settle
componentsblood
5. Acids and Bases
Because of water’s ___________ solutes readily dissolve in _________ creating a variety of solutions
When a substance containing H is ______________ in water the substance might release _____ ions (H+) because of the strong ________________ to the negatively charged ___________ atoms in water molecules
Acids – substances that release H+ ions when _____________ in water
More _______ released the more _________ the solution
polarity
H
attraction
oxygen
dissolved
dissolved
H+ acidic
water
Chemistry in Biology
Substances that release hydrogen ions (H+) when dissolved in water are called acids.
Substances that release hydroxide ions (OH–) when dissolved in water are called bases.
Acids and Bases
6.3 Water and SolutionsChapter 6
Acids and Bases (Cont.) Bases – substances that _____________ hydroxide
ions (OH-) when dissolved in water More OH- released the more _________ the solution
pH is a measure of the ______________ of H+ in a solution
Buffers are _____________ that can react with acids or ___________ to maintain pH within _______________ ranges; very important to living organisms who cannot ______________ large changes in pH
Ex. Blood pH is maintained between _____ and ______
release
basic
concentration
substances
bases
acceptabletolerate
7.0 7.4
Chemistry in Biology
The measure of concentration of H+ in a solution is called pH.
Acidic solutions have pH values lower than 7. Basic solutions have pH values higher than 7.
pH and Buffers
6.3 Water and SolutionsChapter 6
Chemistry in Biology
Buffers are mixtures that can react with acids or bases to keep the pH within a particular range.
6.3 Water and SolutionsChapter 6
6.4 The Building Blocks of Life
Organisms are made up of carbon-based molecules
Carbon-containing compounds are ____________ compoundsorganic
Organic Chemistry
The element carbon is a component of almost all biological molecules.
6.4 The Building Blocks of Life
Chemistry in BiologyChapter 6
Carbon has four electrons in its outermost energy level.
One carbon atom can form four covalent bonds with other atoms.
Chemistry in Biology
Carbon compounds can be in the shape of straight chains, branched chains, and rings.
6.4 The Building Blocks of LifeChapter 6
Why is C so important to life?
C has ______ valence electrons and can form _______ covalent bonds forming molecules with __________ chains, branched chains and ________
C atoms can be joined together to form ____________ molecules called macromolecules
Macromolecules are _______________ - large molecules made from ______________ units of identical or nearly _________ compounds called ________________ that are linked together by a series of _______________ bonds
44
straight rings
large
polymers
repeating
identicalmonomers
covalent
4 Major Organic Compounds/Macromolecules
(Table 6.1, pg. 167)1. Carbohydrates – compounds that contain C, ____ and O in a ratio of 1:2:1; usually occur in ___________ Have the formula (CH2O)n where n ranges from _____ to ______
forming simple sugars or _____________________ Ex. Glucose Function – energy __________
2 monosaccharides joined together form a _______________ Ex. Sucrose and ___________ Function - ___________ source
Longer ______________ molecules are called polysaccharides Ex. Glycogen, _____________ and starch Function – energy storage and _____________ support
Hrings
3 7monosaccharides
sourcedisaccharide
lactoseenergy
carbohydratecellulose
structural
Chemistry in Biology
Carbohydrates Compounds composed of carbon, hydrogen, and
oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH2O)n
6.4 The Building Blocks of LifeChapter 6
Lipids 2. Lipids – compounds composed of C and H
and very little __________ Fats, oils, ___________ and steroids Structure - ___________ molecule and fatty acid
_________ Primary function - __________ storage Hydrophobic – do not _____________ in water Saturated fats – fats with _________ acid chains
composed of only C-C __________ bonds Tend to be ___________ at room temperature ____________ fats “bad” fats
oxygen
waxes
glycerolchain(s)
energy
dissolve
fatty
singlesolids
animal
Lipids (cont.) Unsaturated fats – fats with fatty ________ chains
composed of at least ______ C-C double bond Tend to be ______________ at room temperature Plant _________ “good” fats
Phospholipids – special type of _________ responsible for the ____________ and function of cell membranes
Partially dissolve in ____________ because they have a ____________ head and 2 hydrophobic tails
Steroids – important in normal _________ functioning Ex: cholesterol and _______________
acid
1liquids
oils
lipid
structure
waterpolar
cell
hormones
Proteins 3. Proteins – compounds made of small carbon
_______________ called amino _________ Amino acids (a.a.) –small compounds composed of C,
H, O, N and _____ All a.a. have the same general ________________: a
central _________ atom bonded to an amino group, ________ , carboxyl group and an R group or ____________ side chain
_____ different R groups creating 20 different _________ acids
Peptide ____________ are formed when one a.a. is joined to another _________
compounds acids
Sstructure
carbon
hydrogenvariable
20
amino
bonds
a.a
Chemistry in Biology
Amino acids have a central carbon atom.
One of the four carbon bonds is with hydrogen.
The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a variable group (–R).
6.4 The Building Blocks of LifeChapter 6
Proteins (cont.)Based on the R groups contained in
_______________ a.a. proteins can have up to ______ levels of structure
Primary - ____________ of a.a. in a chain and the _______ in which the a.a are joined together
Secondary – unique ___________ shape; either a helix or pleated sheet
Tertiary – continued folding of _____________ based on the interactions of ________ groups; Ex. Globular
Quaternary – interactions of more than ______ protein or _________________ chain
4
numberorder
different
3-D
protein
R
onepolypeptide
Chemistry in Biology
The number and the order in which the amino acids are joined define the protein’s primary structure.
After an amino acid chain is formed, it folds into a unique three-dimensional shape, which is the protein’s secondary structure, such as a helix or a pleat.
6.4 The Building Blocks of LifeChapter 6
Proteins (Cont.)Proteins are ________________ to all living
organismsProvide structural supportTransport ______________Communicate signals_________ up chemical reactionsControl _________ growth
essential
substances
Speed
cell
Nucleic Acids 4. Nucleic acids – compounds made up of
smaller repeating subunits called _____________________ Function: store and _____________ genetic
information Nucleotides are composed of C, H, O, N, and _____
6 Major Nucleotides: adenine (A), ___________ (T), guanine (G), cytosine (____), uracil (U) and ATP (_________________________)
Each is composed of a ______________, sugar and nitrogen base
2 types of nucleic acids: _________ (deoxyribonucleic acid) and RNA (______________________)
nucleotidestransmit
Pthymine
Cadenosine triphosphate
phosphate group
DNA
ribonucleic acid
Chemistry in Biology
Nucleic acids are complex macromolecules that store and transmit genetic information.
Nucleic acids are made of smaller repeating subunits called nucleotides, composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.
6.4 The Building Blocks of LifeChapter 6