Chapter 6

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.


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


Horizontal rows are called periods. Vertical columns are called groups.


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


Atoms of the same element that have the same number of protons and electrons but have a different number of neutrons


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


When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.


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


Covalent bonds

bond that forms when electrons are shared

A molecule is acompound in which the atoms are held together by covalent bonds.


Ionic Bonds


Electrical attraction between two oppositely charged atoms or groups of atoms


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.


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


The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

Energy of Reactions


Energy of the Reaction (cont.)Exergonic reaction - ______________ in

which the products have less energy than the ____________

Energy is _________ off

reaction

reactants

given


This reaction is exothermic and released heat energy.

The energy of the product is lower than the energy of the reactants.


Energy of the Reaction (Cont.)Endergonic reaction – reaction in which the

____________ have more energy than the _______________

Energy is ____________

products

reactants

absorbed


This reaction is endothermic and absorbed heat energy.

The energy of the products is higher than the energy of the reactants.


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


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


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


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.


6.3 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


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


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


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


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



Buffers are mixtures that can react with acids or bases to keep the pH within a particular range.


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.


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


Carbohydrates Compounds composed of carbon, hydrogen, and

oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH2O)n


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


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).


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


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.


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


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.


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Chapter 6

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