chapter 2 cp

8/14/2019 Chapter 2 CP

1/61

Chapter 2

CHEMISTRY

OF

LIFE


2/61

KEY CONCEPT

All living things are made of cells which are based on

atoms and their interactions.


3/61

Cell Theory

All living things are made of cells

All cells come from other cells

The cell is the basic unit of life


4/61

Matter is . . .

Anything that occupies space andhas mass


5/61

Living things consist of atoms of different elements.

An atom is the smallest basic unit of matter. An element is one type of atom.

H

O

Hydrogen atom (H)

Oxygen atom (O)


6/61

What is an element?

A substance made of only one kind of atom

Elements are listed on the periodic table


7/61

How many elements listed on the

periodic table are actually found

in 97% of all living organisms?

10 elements

C CarbonH Hydrogen

N Nitrogen

O Oxygen

Ca Calcium

P Phosphorus

K Potassium

S Sulfur

Na Sodium

Cl Chlorine

Mg Magnesium


8/61

The nucleus has protons and neutrons.

Electrons are in energy levels outside nucleus.

Oxygen atom (O)

Nucleus:

8 protons (+)

8 neutrons

outermost energy level:

6 electrons (-)

inner energy level:

2 electrons (-)

An atom has a nucleus and electrons.


9/61

water (H2O) is a compound

O

HH

_

++

A compound is made of atoms of different elements

bonded together.


10/61

carbon dioxide (CO2)


bonded together.

water (H2O)


11/61

many other carbon-based compounds in living things


bonded together.

water (H2O)

carbon dioxide (CO2)


12/61

Ions form when atoms gain or lose electrons.

An ion is an atom that has gained or lost one or moreelectrons.

positive ions

negative ions

Ionic bonds form between oppositely charged ions.

Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na+) Chloride ion (CI-)

Na loses an

electron to CI ionic bond

gained electron


13/61

Atoms share pairs of electrons in covalent

bonds.

A covalent bond forms when atoms share a pair ofelectrons.

covalent bonds

Oxygen atom (O) Carbon atom (C) Oxygen atom (O)

Carbon dioxide (CO2 )

multiple covalent bonds

diatomic molecules


14/61

KEY CONCEPT

Waters unique properties allow life to exist on Earth.


15/61

What is Osmosis?

the diffusion of water.


16/61

HH

_

++

Life depends on hydrogen bonds in water.

Water is a polar molecule. Polar molecules have slightly charged regions.

Nonpolar molecules do not have charged regions.

Hydrogen bonds form between slightly positive

hydrogen atoms and slightly negative atoms.


17/61

Hydrogen bonds are responsible for three important

properties of water. high specific heat

cohesion

adhesion


18/61

Many compounds dissolve in water.

A solution is formed when one substance dissolves inanother.

A solution is a homogeneous mixture.

Solvents dissolve other substances (solvents are

greater than solutes in number) Solutes dissolve in a solvent.

solution

Solvent

Solute


19/61

Like dissolves like.

Polar solvents dissolve polar solutes.

Nonpolar solvents dissolve nonpolar solutes.

Polar substances and nonpolar substances generally

remain separate.


20/61

Some compounds form acids or bases.

An acid releases a hydrogen ion when it dissolves inwater.

high H+ concentration

pH less than 7

more acidic because there are more H+ ions

stomach acid pH between 1 and 3


21/61

A base removes hydrogen ions from a solution.

low H+ concentration

pH greater than 7

bile pH between 8 and 9

more basic because there is less H+


22/61

A neutral solution has a pH of 7. (the H+ ions are equal to

the OH- ions)pure water pH 7

H+ (+) OH- = H2O


23/61

What would result if you added an acid to a

neutral solution?

Water is neutral H2O

Acid + neutral = Acid

pH 6 + pH7 = pH 6.5

H+ ions added to H2O = H20 + H+(shifted toward the acid end of the pH scale


24/61


25/61

0100 (1.0)1410-14

110-1 (0.1)1310-13

210-2 (0.01)1210-12

310-3 (0.001)1110-11

410-4(0.0001)1010-10

510-5(0.00001)910-9

610-6(0.000001)810-8(0.00000001)

710-7(0.0000001)710-7(0.0000001)

810-8(0.00000001)610-6(0.000001)

910-9510-5(0.00001)

1010-10410-4(0.0001)

1110-11310-3 (0.001)

1210

-12

210

-2

(0.01)

1310-13110-1 (0.1)

1410-140100 (1.0)

MpOH[OH-]pH[H+] M


26/61

Household ammonia has a pH of 12; household bleach

has a pH of 13. What is the difference in the number of

H+ ions in the two solutions?

The ammonia has 10 times as many H+ ions as the bleach.

pH 12 has: 1 x 10-12H+ and 1 x 10-2OH-

pH 13 has: 1 x 10-13H+ and 1 x 10-1OH-


27/61

VOCABULARY 2.1

1. Atom

2. Element

3. Compound

4. Ion

5. Ionic bond

6. Covalent bond

7. Molecule


28/61

VOCABULARY 2.1

Atom smallest basic unit of matter

Element one particular type of atom, cannot be brokendown into a simpler substance by ordinary chemical

means

Compound two or more atoms bonded together in a

fixed ratio Ion an atom that has gained or lost one or more

electrons

Ionic bond forms through electrical force between

oppositely charged atoms Covalent bond forms when atoms share a pair of

electrons

Molecule two or more atoms held together by covalent

bonds


29/61


30/61

Carbon atoms have unique bonding

properties.

Carbon forms covalent bonds with up to four other atoms,including other carbon atoms.

Carbon-based molecules have three general types of

structures.

straight chain branched chain

ring


31/61

Many carbon-based molecules are made of many small

subunits bonded together.

Monomers are the individual subunits.

Polymers are made of many monomers.


32/61

Four main types of carbon-based molecules are found in

living things.

Carbohydrates

Proteins

Lipids

Nucleic Acids


33/61

What property of carbon makes it

perfect for the building block of

life?

Carbon forms covalent bonds


34/61


living things.

Carbohydrates are made of carbon, hydrogen, and

oxygen.


35/61


living things.

Carbohydrates are made of carbon, hydrogen, and

oxygen.

Carbohydrates include

sugars and starches. Monosaccharides are

simple sugars.

Polysaccharides include

starches, cellulose, andglycogen.


36/61

Carbohydrates can be broken down to provide

energy for cells.

Some carbohydrates are part of cell structure.

Polymer (starch)

Starch is a polymer of

glucose monomers that

often has a branched

structure.

Polymer (cellulose)

Cellulose is a polymer

of glucose monomers

that has a straight, rigid

structure

monomer


37/61

Many contain carbon chains called fatty acids.

Fats and oils contain fatty acids bonded to glycerol.

Lipids are nonpolar molecules that include fats, oils, and

cholesterol.

Triglyceride


living things.


38/61

Lipids have several different functions.

broken down as a source of energy

make up cell membranes

used to make hormones


39/61


40/61

Phospholipids make up all cell membranes.

Polar phosphate head

Nonpolar fatty acid tails

Phospholipid

Phospholipids have

KINKY tails!


41/61

Proteins are polymers of amino acid monomers.

Twenty different amino acids are used to build

proteins in organisms.


living things.


42/61

Amino acids differ in side groups, or R groups.





43/61

Amino acids are linked by peptide bonds.


Amino acids differ in side groups, or R groups.




44/61

Proteins differ in the number and order of amino acids.

Amino acids interact to give a protein its shape.

Incorrect amino acids change a proteins structure

and function.

hydrogen bond

Hemoglobi

n

Four main types of carbon based molecules are found in


45/61

Nucleic acids are polymers of monomers called

nucleotides.


living things.


46/61

Nucleotides are made of a sugar, phosphate

group, and a nitrogen base.

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)


nucleotides.


47/61

DNA stores genetic

information.


nucleotides.

Nucleotides are made of a sugar, phosphate

group, and a nitrogen base.

RNA builds proteins.

DNA

RNA


48/61

Where do most of a cells chemical

reactions (metabolism) occur?

The liquid part of a cell called the

cytoplasm


49/61


living things.

Carbohydrates

Proteins

Lipids

Nucleic Acids


50/61

KEY CONCEPT

Life depends on chemical reactions.

B d b k d f d i h i l


51/61

Bonds break and form during chemical

reactions.

Chemical reactions change substances into different onesby breaking and forming chemical bonds.

Reactants are changed during a chemical reaction.

Products are made by a chemical reaction.


52/61

A reaction is at equilibrium when reactants and products

form at the same rate.

CO2 + H2O H2CO3

Bond energy is the amount of energy that breaks a bond.

Energy is added to break bonds.

Energy is released when bonds form.


53/61

Chemical reactions release or absorb energy.

Activation energy is the amount of energy that needsto be absorbed to start a chemical reaction.


54/61


55/61

Endothermic reactions absorb more energy than they

release.

Reactants have lower bond energies than products.

Energy is absorbed by the reaction to make up the

difference.


56/61

KEY CONCEPT

Enzymes are catalysts for chemical reactions in livingthings.


57/61

A catalyst lowers activation energy.

Catalysts are substances that speed up chemicalreactions.

decrease activation energy

increase reaction rate (reactions happen faster at lower

energy levels)


58/61

Enzymes allow chemical reactions to occur under tightly

controlled conditions.

Enzymes are catalysts in living things.

Enzymes are needed for almost all processes.

Most enzymes are proteins.


59/61

Disruptions in homeostasis can prevent enzymes from

functioning. Enzymes function best in a small range of conditions.

Changes in temperature and pH can break hydrogen

bonds.

An enzymes function depends on its structure.


60/61

An enzymes structure allows only certain reactants to

bind to the enzyme. substrates

active site

substrates

(reactants)

enzyme

Substrates bind to an

enzyme at certain places

called active sites.


61/61

The lock-and-key model helps illustrate how enzymes

function. substrates brought together

bonds in substrates weakened, new bonds formed

which creates a new substance

Substrates bind to an

enzyme at certain places

called active sites.

The enzyme brings

substrates together,

forms new bonds,

which forms a new

The catalyzed reaction forms

a product that is released

from the enzyme.

chapter 2 cp

Documents