Chemical Basis of Life NEW

8/9/2019 Chemical Basis of Life NEW

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Did you know thatyou are a living

example ofchemistry?


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The average human

body contains:

Enough iron to make a3-inch nail

Sulfur to kill all fleas onan average-sized dog


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Carbon to make 900

pencils

Potassium to fire a toy

cannon

Fat to make 7 bars ofsoap


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Phosphorus to make

2,200 match heads Water to fill a 10-gallon

tank


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AnswerActivity

Sheet #4


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The Chemical Basis of Life


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The Chemical Context of life

MatterAnything that takes up

space and has mass


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ATOM

The smallest stableparticle of matter

Composed of

protons, neutrons,and electrons


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All matter ismade up of tiny

particles called

atoms.


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Atoms are thebasic building

blocks of allmatter, including

life.


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What is the relationship of

the following?

Atoms

Molecules

Elements

Compounds


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Ions

an atom that gains orloses electrons to

become stable


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Cationa positively charged

ion formed when an

atom loses electrons


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Aniona negatively charged

ion formed when an

atom gains electrons


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an electrically charged atom


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Chemical Bonding


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Ionic Bond

an attraction

between a cation

and an anion


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Ionic Bond

formed when

electrons are

transferred from one

atom to another atom


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Covalent Bond

Formed when

atoms share

electrons


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Covalent Bond

Hydrogen atoms form

single bonds ( 2 electrons

are shared by the atoms )

H H( Hardest to break )


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Oxygen atoms form

two bonds (4 electronsshared )

O = O


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Nitrogen atoms form

three bonds (6 electrons

shared )

N NEasiest to break


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Carbon atoms form four

bonds (8 electrons shared)

O=C

=O


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MOLECULE

formed when atomsare joined together by

covalent bonds


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OtherTypes of

Atomic & MolecularInteractions


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PolarInteractions

Attraction between

partially charged (polar)

molecules and other polar

or charged molecules

Similar to ionic bonding


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A water molecule

is polar


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The OXYGEN atom onone end of the molecule

is partially negative The HYDROGEN atom on

the other end is partiallypositive


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Hydrogen bondingInteraction between

a hydrogen atomand two strong

electronegativegroups


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Water has hydrogen

bondsA single water molecule

may be involved in asmany as 4 hydrogen

bonds at the same time.


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Water is extremelycohesive:

there is an attractionbetween molecules of the

same substance.


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How is the insect ableto rest on top of the

water?


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strong attractionbetween water

molecules producesa force called

surface tension


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Why do you get the volume of

water in the graduated cylinderusing the lower meniscus?

This iscaused by

ADHESION.


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Adhesion

is theattraction

between

molecules

of different

substances


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Why study chemistry in

biology?

- body functions depend on

cellular functions

- cellular functions result from

chemical changes


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- biochemistry helps to

explain physiological

processes, and develop new

drugs and methods for

treating diseases


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Justify your existencein this world!

How can you show thatyou are living your life

to the fullest?

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