Biology Test #1

Front 1

Characteristics of life

Back 1

Complex, organized structure
Response to stimuli - a change outside (or inside) leads to another change
Homeostasis - the ability to maintain the structure and regulate the internal environment.
Ability to acquire material and energy -The material and energy are often transformed
Growth
Reproduction - either sexual or asexual DNA is genetic information, the “blueprint” for the offspring
Ability to evolve - to change to fit the environment

Front 2

ecosystem

Back 2

A community together with its nonliving souroundings

Front 3

community

Back 3

two or more populations of different species living and the interaction in the same area

Front 4

species

Back 4

very similiar, potentially interbreeding organisms

Front 5

population

Back 5

members of one species inhabiting the same area

Front 6

muticellular organisms

Back 6

an indivisual living thing composed of many cells

Front 7

organ system

Back 7

two or more organs working together in the execution of a specific bodily function

Front 8

organ

Back 8

a structure usually composed of several tissue types that form a functional unit

Front 9

tissue

Back 9

a group of similiar cells that perform a specific function

Front 10

cell

Back 10

the smallest unit of life

Front 11

organelle

Back 11

a structure within a cell that performs a specific function

Front 12

molecule

Back 12

a combination of atom

Front 13

atom

Back 13

the smallest particle of an element thet retains the properties of the element

Front 14

subatomic particle

Back 14

particles that make up an atom

Front 15

stimuli

Back 15

Organisms react to external and internal stimuli.

Some reactions are slow and can’t be seen.

Front 16

homeostasis

Back 16

the ability to maintain the structure and regulate the internal environment.In order to stay alive and function, organisms must keep the conditions within their bodies fairly constant.

Front 17

Ability to acquire material and energy

Back 17

The material and energy are often transformed .
Energy is used to maintain a high level of complexity and organization, to grow, and to reproduce.

Front 18

heterotrophs

Back 18

Organisms can take in nutrients (food) for raw materials and energy

Front 19

autotrophs

Back 19

Or they can use sunlight for energy (photosynthesis) to produce energy-rich sugar molecules

Front 20

Metabolism

Back 20

is basically the sum total of all of the chemical reactions that occur within an organism.
Metabolism changes the raw material and energy into the forms which are needed for maintenance, growth, reproduction, etc .

Front 21

evolution

Back 21

If the environment changes, then the population of organisms must change to fit the environment or face the possibility of extinction.

Front 22

mutation

Back 22

The evolutionary changes are usually slow, taking several generations and occur by the accumulation of DNA changes known as

Front 23

domains

Back 23

Each of the major organizational groups are called

Front 24

There are two prokaryotic domains;

Back 24

Bacteria and Archaea and a eukaryotic domain; Eukarya.

Front 25

kingdom

Back 25

Within the domains are at least 6 groups known as
Each kingdom has different attributes which define them.

Front 26

prokaryotes

Back 26

-no nucleus or nuclear envelope
-genetic material in a "nucleoid region"
-no organelles or internal membranes

Front 27

Eukaryotes

Back 27

-nucleus w/ a nuclear envelope
-genetic material within the nucleus
-contains cytosol with membrane-bound organelles

Front 28

bacteria-cell type, cell #, nutritional Method

Back 28

prokaryotic
unicellular
absorb/photo

Front 29

Archaea- Cell type, Cell #, NM

Back 29

Pro
Uni
absorb/photo

Front 30

protista- ct, c#, NM

Back 30

eukary
uni
absorb/photo

Front 31

fungi-ct,c#, NM

Back 31

eukary
multi
absorb

Front 32

plantae-ct, c#, NM

Back 32

eukary
multi
photo

Front 33

animalia-ct, c#, NM

Back 33

eukary
multi
ingestion

Front 34

The 3 most stable subatomic particles are

Back 34

neutrons, protons, and electrons

Front 35

protons

Back 35

are positively charged particles found at the core, or nucleus, of the atom

Front 36

neutrons

Back 36

are uncharged particles found at the core, or nucleus, of the atom.

Front 37

electrons

Back 37

are light, negatively charged particles that orbit around the nucleus in electron shells

Front 38

element

Back 38

is a substance that can’t be broken down into other substances by chemical reactions

Front 39

atomic weight

Back 39

of an element is the number of protons plus the number of neutrons

Front 40

isotopes

Back 40

Isotopes are atoms of the same element which have different atomic weights (diff # pf protons and neutons)

Front 41

electron orbitals

Back 41

are the three-dimensional space around the nucleus of an atom where an electron will be found 90% of the time

Front 42

The electron orbitals of an atom are arranged in _______ based on their ________.

Back 42

electron shells
energy level

Front 43

An atom with an incomplete (partially full) electron shell is ______ whereas an atom with a full electron shell is ____, or not chemically active

Back 43

reactive
inert

Front 44

chemical behavior of an atom is determined by

Back 44

the number of electrons in the outermost electron shell

Front 45

A chemical bond

Back 45

is an attraction that holds two atoms together
A reactive atom will try to fill the valence shell by interacting with other atoms

Front 46

a molecule

Back 46

is two or more atoms held together by chemical bonds
The smallest unit that retains the physical and chemical properties of a compound

Front 47

ions

Back 47

is a charged atom or molecule. It is charged because it has either lost or gained electrons
If an atom has an almost empty or an almost full outer electron shell it is more likely to form an ion.

Front 48

anion

Back 48

is a negatively charged atom or molecule. It has gained an electron

Front 49

cation

Back 49

is a positively charged atom or molecule. It has lost an electron

Front 50

A chemical bond is formed through

Back 50

The gaining, losing, or sharing of electrons

Front 51

After sodium loses an electron, it is

Back 51

positive ion.

Front 52

After chlorine gains an electron, it is

Back 52

A negative ion

Front 53

ionic compounds

Back 53

Ionic compounds are called salts and usually form crystals as a solid. 
Ionic bonds are strong in crystals but break easily in water.

Front 54

covalent bond

Back 54

is a bond formed when two atoms share pairs of electrons.

Front 55

nonpolar covalent bond

Back 55

ex H gas
same charge on both nuclei
electrons spend equal time near each nucleus
covalent bond is a covalent bond in which the sharing of the electron pair is equal

Front 56

polar covalent

Back 56

covalent bond is a covalent bond in which the sharing of the electron pair is unequal.
ex.water

Front 57

electronegativity

Back 57

defined as an atom’s ability to attract and hold electrons. Assigned a numerical value. The higher the #, the more electronegative an atom is

Hydrogen = 2.2
Carbon = 2.6
Nitrogen = 3.0
Oxygen= 3.4

Atoms with higher electronegativity have a more positively-charged nucleus, and will hold onto the electron pair more strongly than atoms with significantly lower electronegativity.

Front 58

hydrogen bond

Back 58

is formed by the charge attraction when a hydrogen atom which is covalently bonded to one atom is attracted to a second atom.

Front 59

What kind of bonds form between water molecules?

Back 59

hydrogen

Front 60

hydrophillic

Back 60

describes the property of having an affinity for water. easily dissolves in water

Front 61

hydrophobic

Back 61

describes the property of not having an affinity for water
Nonpolar substances
The polarity of water molecules makes water a poor solvent for molecules which do not have charged regions

Front 62

hydrophobic interaction

Back 62

hydrophobic molecules clump together in water because of

Front 63

Water Molecules Tend To Stick Together

Back 63

Water has cohesive behavior which is the result of hydrogen bonding between the water molecules and the other molecules and includes cohesion, andsurface tension.

Front 64

COHESION

Back 64

Attraction between like molecules

Front 65

Surface Tension

Back 65

cohesion among water molecules at the surface of water

Front 66

>>>Acids and basesWater molecules can

Back 66

dissociate

Front 67

hydrogen atom of one water molecule leaves its electron behind and forms a

Back 67

hydrogen ion (H+) and a hydroxide ion (OH-)
dissociate

Front 68

In pure water

Back 68

the number of H+ ions = the number of OH- ions

Front 69

If the solution is acidic

Back 69

then the number of H+ ions is greater than the number of OH- ions.

Front 70

solution is basic

Back 70

if the number of OH- ions is greater than the number of H+ ions

Front 71

An acid is a proton

Back 71

proton donor, or a substance which increases the concentration of H+ in a solution.

Front 72

base is a proton

Back 72

acceptor, or a substance which reduces the concentration of H+ in a solution

Front 73

pH scale

Back 73

is a scale used to measure the acidity of solutions.

The scale ranges from 0 to 14.

For a neutral solution pH = 7
For an acidic solution pH < 7
For a basic solution pH > 7

Front 74

Because the pH scale is a logarithmic scale

Back 74

a change of one pH unit represents a tenfold change in the concentration of H+.

Front 75

Most biological solutions are between

Back 75

pH 6 and pH 8

Front 76

Buffers

Back 76

are substances that prevent large, sudden changes in pH.

Buffers are combinations of H+ donors and H+ acceptors

Buffers function by accepting H+ ions from solution when they are in excess, and donating H+ ions to the solution when the supply is depleted.


Example: Bicarbonate buffer

Front 77

Three properties of water help keep temperature stable:

Back 77

1) High specific heat
2) High heat of vaporization
3) High heat of fusion

Front 78

Specific heat

Back 78

is the amount of energy that must be absorbed or lost for one gram of matter to change its temperature by one degree Celsius.

Front 79

Vaporization (evaporation

Back 79

is the transformation of matter from a liquid to a gas.

Front 80

Heat of vaporization

Back 80

is the quantity of heat a liquid must absorb for 1 gram to be converted to the gaseous state, or to evaporate.


-Leads to cooling of the surface of a liquid when during evaporation.

Front 81

Water has a high heat of fusion

Back 81

Water has a high heat of fusion and freezes much slower than other liquids.

When water freezes, it forms an unusual solid, Ice which floats.

Front 82

Organic molecules

Back 82

are molecules containing carbon
except water

Front 83

carbon atoms

Back 83

Carbon atoms are the most versatile building blocks of molecules


Carbon has a valence of 4.
Can bind to 2, 3, or 4 other atoms.

Front 84

Functional groups

Back 84

are small characteristic groups of atoms which are frequently bonded to the carbon skeleton of organic molecules.
Another factor which leads to the versatility of organic molecules


Have specific chemical and physical properties.
Are regions of organic molecules which are frequently chemically reactive.
Behave consistently from one organic molecule to another.
Can determine the chemical properties of the organic molecule in which they are located.

Front 85

Hydroxyl group

Back 85

---Hydroxyl group is a functional group of a hydrogen atom bonded to an oxygen atom which is bonded to a carbon atom (of the carbon skeleton).
Is a polar group

-Involved in condensation (dehydration) and hydrolysis reactions

Front 86

carbonyl group

Back 86

Polar functional group.
Extremely hydrophilic.
Makes parts of a molecule water soluble.

Front 87

Carboxyl group

Back 87

Carboxyl group is a functional group in which a carbon atom is double bonded to an oxygen atom (like a carbonyl) and is also single bonded to the oxygen atom of a hydroxyl group.
Since this group can donate a proton, it is acidic
-Involved in peptide bonds between amino acids

-Since this group can donate a proton, it is acidic
-Involved in peptide bonds between amino acids

Front 88

Amino groups

Back 88

Amino groups are functional groups in which two hydrogen atoms are bonded to a nitrogen atom which is bonded to a carbon atom (of the carbon skeleton).


-Acts as a weak base (similar to ammonia) because it accepts protons.
 -Involved in peptide bonds between amino acids

Front 89

sulfhydryl (forms, found in)

Back 89

Forms disulfide bonds within and between proteins.

Found in numerous proteins in biological systems.

Front 90

A peptide bond forms between which two functional groups?

Back 90

Carboxyl and amino

Front 91

Phosphate group

Back 91

Phosphate group is a functional group which is the dissociated form of phosphoric acid (H3PO4)
Acts as an acid because of the ability to donate protons.
-Links nucleotides together to form nucleic acids
-Important in cellular energy storage and energy transfer.
Example: ATP

Front 92

Biological molecules are often put together in

Back 92

Biological molecules are often put together in subunits, or modules, called monomers.

---the simple molecules combined to form more complex ones

---monomers into polymers

Front 93

Polymers

Back 93

are chains of similar building blocks or monomers.

Front 94

-A Monomer

Back 94

is a subunit (or building block) of a polymer.

Front 95

The reaction that forms a polymer from monomers is

Back 95

The reaction that forms a polymer from monomers is a dehydration synthesis (or condensation reactions).

Front 96

Dehydration synthesis

Back 96

is a reaction in which the covalent linkage of the monomers is accompanied by the “removal” of a water molecule.

Front 97

Hydrolysis

Back 97

is the breaking of the covalent bond between two monomers by the addition of water.

Front 98

Carbohydrates

Back 98

are used as fuels and building material
Carbohydrates are organic molecules made of sugars and their polymers.
Carbohydrates are classified by the number of simple sugars.

Front 99

monosaccharides.

Back 99

Monomers are simple sugars
carbohydrate
Monosaccharides are simple sugars in which carbon, hydrogen, and oxygen occur in the ratio of 1-2-1 for C, H, and O.
Major source of nutrients for cells. -Glucose is the most common -Can be produced by photosynthetic organisms from CO2, H2O, and light

Front 100

Monosaccharides can be joined to form

Back 100

disaccharides and polysaccharides

Front 101

Disaccharides

Back 101

are molecules which consist of two monosaccharides joined by a glycosidic linkage.
maltose
lactose
sucrose

Front 102

Glycosidic linkage

Back 102

is a covalent bond formed by a dehydration synthesis between two sugar monomers.

Front 103

Each carbon has a hydroxyl group attached to it except one which is a

Back 103

carbonyl group.

Front 104

In aqueous solutions

Back 104

monosaccharides with 5 or more carbons in the skeleton form ring structures.
The chemical equilibrium favors the ring structure over the straight chain

Front 105

Polysaccharides

Back 105

are macromolecules that are polymers of a few hundred or thousand monosaccharides.

Formed by enzyme-mediated condensation reactions.
-Biological functions Energy storage(starch and glycogen) (see fig 3-3) Structural support (cellulose and chitin) (see figs 3-4 and 3-5)

Formed by enzyme-mediated condensation reactions.
-Biological functions Energy storage(starch and glycogen) (see fig 3-3) Structural support (cellulose and chitin) (see figs 3-4 and 3-5)

Front 106

Storage polysaccharide

Back 106

Stored sugars can be hydrolyzed as needed. Stored in muscle and liver.

Front 107

-Starch

Back 107

is a glucose polymer that is used as a storage polysaccharide in plants.

Front 108

---Glycogen

Back 108

is a glucose polymer that is used as a storage polysaccharide in animals.
If there is more glucose in your bloodstream than your body needs, the excess glucose is linked together and stored as glycogen in your muscles and liver.

When energy is needed, glycogen is quickly broken down to release glucose into the bloodstream for short-term energy needs.

Once glycogen stores are full, excess glucose gets converted to fat for long-term energy needs.

Front 109

Carb-loading

Back 109

A process by which athletes are able to double or triple the amount of glycogen stored in their muscles. Used to delay the onset of muscle fatigue.

2 phase process:
Depletion phase- about a week before competition. Extremely low-carb diet and rigorous exercise.

Loading phase -2 days before competition. Super high-carb diet and no exercise. Achieves a blood glucose level that is higher than necessary, so excess glucose gets converted to glycogen.

Front 110

Water Weight

Back 110

The first stages of any diet usually involve rapid and dramatic weight loss.
Water is heavy 4-ounces to each molecule
Glycogen is nonpolar and does not deplete as fast (fat)

This is because glycogen is being depleted in the muscles and liver as caloric intake is reduced.

Every ounce of glycogen in the body can have as much as four ounces of water bound to it.

Front 111

Structural polysaccharides include

Back 111

cellulose and chitin

Front 112

-Cellulose

Back 112

is a linear unbranched polymer of glucose

most abundant organic molecule on the planet.

-differs from starch in the type of linkage 
-different linkage gives different three-dimensional structure.
-cellulose reinforces plant cell walls.

Front 113

Hydrogen bonds

Back 113

hold the cellulose strands together-cellulose cannot be digested by most animals because they lack the enzyme that can hydrolyze the linkage in cellulose.

Front 114

Chitin

Back 114

is a structural polysaccharide that is a polymer of an amino sugar.

forms the exoskeleton of arthropods (insects, crawfish, etc.)
-found in the cell walls of some fungi.

Front 115

Lipids

Back 115

are mostly nonpolar hydrophobic molecules composed mainly of carbon and hydrogen
Lipids are a diverse group of organic molecules that are insoluble in water, but will dissolve in nonpolar solvents (e.g., ether, chloroform, benzene)

Front 116

-Important lipids are grouped into 3 types:

Back 116

1) fats, oils, and waxes2) phospholipids3) steroids.

Front 117

Oils, Fats and Waxes
Characteristics:

Back 117

-composed of carbon, hydrogen and oxygen
 -contain 1 or more fatty acids
 -usually no ring structure

Front 118

--Fats and oils are

Back 118

macromolecules constructed from fatty acids and glycerol.

Front 119

---Glycerol

Back 119

is a three-carbon molecule with one hydroxyl group per carbon.

Front 120

Fatty acids (FA) are

Back 120

hydrocarbon chains with a carboxyl group at one end

Front 121

The hydrocarbon chain

Back 121

or tail, is hydrophobic and not water soluble.
-The tail has a long carbon skeleton usually with an even number (16-18) of carbon atoms.
-The carboxyl group, or head, has the properties of a carboxylic acid.


The FA group is linked through the head to the glycerol and each hydroxyl group on the glycerol can form a linkage with a fatty acid.

Front 122

Triglyceride

Back 122

is a fat composed of three fatty acids bonded to one glycerol by
ester linkages.

Front 123

Function of fats and oils:

Back 123

Energy storage.
One gram of fat stores twice as much energy in its chemical bonds as one gram of polysaccharide.
-Because of the higher energy per gram, energy storage is more compact with fats and oils than with carbohydrates.

Front 124

Olestra

Back 124

Fake Fat”-designed to be similar to fats in taste and texture.

Cannot be digested by humans.

Instead of being a triglyceride with 3 fatty acids linked to a glycerol, it has 8 fatty acids attached to a molecule of sucrose.


It still stimulates the taste buds on your tongue that tell your brain that you are eating fat.

But because the molecule is so complex in shape, it prevents your body’s digestive chemicals from grabbing onto it and breaking it down.

Passes through your digestive system without being digested.

Front 125

Fats
Humans store fat in
Fat also insulates
Fats exist as 2 main types

Back 125

adipose tissue cells, which swell and shrink as fat is added to, or taken from them.

the body and protects vital organs.

: saturated and unsaturated.

Front 126

SATURATED

Back 126

No double bonds between carbons

Maximum number of hydrogen atoms bonded to the carbon of the skeleton (saturated)

Usually solid at room temperature

Most animals store fats

Front 127

UNSATURATED

Back 127

One or more double bonds between carbons

Chain kinks at each double bond, so individual chains cannot pack close enough together to solidify easily.

Usually liquid at room temperature

Most plants store oils

Front 128

Waxes (linked to?,found in)

Back 128

are similar to fats and oils except the fatty acids are linked to large, long chain alcohols instead of glycerol.Waxes are found in plants where waterproofing is needed and are used to build structures (i.e., beehives)

Front 129

--Phospholipids

Back 129

are compounds with molecular building blocks of glycerol, two
fatty acids, a phosphate group and usually a small chemical group attached to the
phosphate group.


Phospholipids have 2 ends that behave completely differently in water.

Hydrophilic heads and hydrophobic tails.

When phospholipids are added to water, they self-assemble into a bi-layer that shield their hydrophobic portion from water.

Front 130

Steroids

Back 130

Class of lipids that includes many hormones.

Characterized by a carbon skeleton consisting of 4 fused rings with various functional groups attached.

Includes cholesterol, a component of animal cell membranes. Used as a molecular precursor for many steroids

Front 131

Proteins

Back 131

are the molecular tools for most cellular functions.-Proteins are polymers of amino acids arranged in a specific linear sequence and are linked by peptide bonds.
Range in length from a few monomers to more than a thousand.-Each protein has a unique linear sequence of amino acids -Proteins are abundant, making up 50% (or more) of some cells dry weight.

Front 132

Amino acids are joined into chains by

Back 132

dehydration synthesis

Front 133

Peptide bonds

Back 133

are covalent bonds formed by a dehydration synthesis that links the carboxyl group of one amino acid to the amino group of
another amino acid.

Front 134

Four levels of protein structure

Back 134

Primary structure
Secondary structure
Tertiary structure
Quaternary structure (when a protein has more than one polypeptide chain)

Front 135

-Important lipids are grouped into 3 types:

Back 135

1) fats, oils, and waxes2) phospholipids3) steroids.

Front 136

Oils, Fats and Waxes
Characteristics:

Back 136

-composed of carbon, hydrogen and oxygen
 -contain 1 or more fatty acids
 -usually no ring structure

Front 137

--Fats and oils are

Back 137

macromolecules constructed from fatty acids and glycerol.

Front 138

---Glycerol

Back 138

is a three-carbon molecule with one hydroxyl group per carbon.

Front 139

Fatty acids (FA) are

Back 139

hydrocarbon chains with a carboxyl group at one end

Front 140

The hydrocarbon chain

Back 140

or tail, is hydrophobic and not water soluble.
-The tail has a long carbon skeleton usually with an even number (16-18) of carbon atoms.
-The carboxyl group, or head, has the properties of a carboxylic acid.


The FA group is linked through the head to the glycerol and each hydroxyl group on the glycerol can form a linkage with a fatty acid.

Front 141

Triglyceride

Back 141

is a fat composed of three fatty acids bonded to one glycerol by
ester linkages.

Front 142

Function of fats and oils:

Back 142

Energy storage.
One gram of fat stores twice as much energy in its chemical bonds as one gram of polysaccharide.
-Because of the higher energy per gram, energy storage is more compact with fats and oils than with carbohydrates.

Front 143

Olestra

Back 143

Fake Fat”-designed to be similar to fats in taste and texture.

Cannot be digested by humans.

Instead of being a triglyceride with 3 fatty acids linked to a glycerol, it has 8 fatty acids attached to a molecule of sucrose.


It still stimulates the taste buds on your tongue that tell your brain that you are eating fat.

But because the molecule is so complex in shape, it prevents your body’s digestive chemicals from grabbing onto it and breaking it down.

Passes through your digestive system without being digested.

Front 144

Fats

Back 144

Humans store fat in adipose tissue cells, which swell and shrink as fat is added to, or taken from them.

Fat also insulates the body and protects vital organs.

Fats exist as 2 main types: saturated and unsaturated.

Front 145

SATURATED

Back 145

No double bonds between carbons

Maximum number of hydrogen atoms bonded to the carbon of the skeleton (saturated)

Usually solid at room temperature

Most animals store fats

Front 146

UNSATURATED (bonds,solid or liquid, ex)

Back 146

One or more double bonds between carbons

Chain kinks at each double bond, so individual chains cannot pack close enough together to solidify easily.

Usually liquid at room temperature

Most plants store oils

Front 147

Waxes

Back 147

are similar to fats and oils except the fatty acids are linked to large, long chain alcohols instead of glycerol.Waxes are found in plants where waterproofing is needed and are used to build structures (i.e., beehives)

Front 148

--Phospholipids(building blocks of, 2 ends)

Back 148

are compounds with molecular building blocks of glycerol, two
fatty acids, a phosphate group and usually a small chemical group attached to the
phosphate group.


Phospholipids have 2 ends that behave completely differently in water.

Hydrophilic heads and hydrophobic tails.

When phospholipids are added to water, they self-assemble into a bi-layer that shield their hydrophobic portion from water.

Front 149

Steroids

Back 149

Class of lipids that includes many hormones.

Characterized by a carbon skeleton consisting of 4 fused rings with various functional groups attached.

Includes cholesterol, a component of animal cell membranes. Used as a molecular precursor for many steroids

Front 150

Proteins

Back 150

are the molecular tools for most cellular functions.-Proteins are polymers of amino acids arranged in a specific linear sequence and are linked by peptide bonds.
Range in length from a few monomers to more than a thousand.-Each protein has a unique linear sequence of amino acids -Proteins are abundant, making up 50% (or more) of some cells dry weight.

Front 151

Amino acids are joined into chains by

Back 151

dehydration synthesis

Front 152

Peptide bonds

Back 152

are covalent bonds formed by a dehydration synthesis that links the carboxyl group of one amino acid to the amino group of
another amino acid.

Front 153

Four levels of protein structure

Back 153

Primary structure
Secondary structure
Tertiary structure
Quaternary structure (when a protein has more than one polypeptide chain)

Front 154

Amino acids

Back 154

are monomer building blocks of a protein. Most consist of a central carbon with four functional groups:

Front 155

Primary structure

Back 155

is the sequence of amino acids in a protein. (see fig 3-20)

-Determined by the genes (DNA).-Different for each different protein-Determines all the remaining structure

Front 156

--Secondary structure

Back 156

is the coiling and folding of a protein’s polypeptide backbone. (caused by hydrogen bonding)
-Contributes to a protein’s overall conformation.
-Stabilized by hydrogen bonding between peptide linkages in the protein backbone

Front 157

The major types of secondary structure are

Back 157

helices and pleated sheets

Front 158

---Tertiary structure

Back 158

is the irregular contortion of a protein backbone due to bonding or interactions between side chains (R groups).

This third level of structure is superimposed on the primary and secondary structures.
Interactions of amino acid side chains

Front 159

Covalent linkage

Back 159

Disulfide bridges

Front 160

Weak interaction

Back 160

Hydrogen bonding
Ionic bonds 
Hydrophobic interactions

Front 161

Why is wet hair easier to style than dry hair?

Back 161

Many proteins in your hair are held together by hydrogen bonds between the amino acids.

Adding water to your hair disrupts the hydrogen bonds between amino acids and causes them to hydrogen bond to water.

When your hair dries, hydrogen bonds can re-form between amino acids