CHEM 46 FINALS

Question 1

a family of substances that are insoluble in water but
soluble in nonpolar solvents and solvents of low polarity,
such as diethyl ether.

Answer 1

Lipids

Question 2

• Fatty acid with a carbon chain in which all C-C bonds are single bonds
• Numbering starts from the end of -COOH group
• Structural notation: it indicates number of C atoms
• Example - Lauric acid has 12 C atoms and no double bonds = (12:0)

Answer 2

Saturated Fatty Acid

Question 2

A polyunsaturated fatty acid is a fatty acid with a carbon chain in which
two or more carbon–carbon double bonds are present.

Answer 2

Polyunsaturated fatty acid

Question 3

A monounsaturated
fatty acid is a fatty acid with a
carbon chain in which one carbon–
carbon double bond is present.

Answer 3

Unsaturated Fatty Acid

Question 4

an unsaturated fatty acid with its
endmost double bond six carbon atoms away from its
methyl end.

Answer 4

Omega (ω)-6 fatty acid

Question 4

An unsaturated fatty acid with its
endmost double bond three carbon atoms away from
its methyl end.

Answer 4

Omega (ω)-3 fatty acids

Question 5

The number of bends in a fatty acid chain increase as the number of double bonds increase.

Answer 5

Space-filling molecules

Question 6

are triesters of glycerol and long-chain carboxylic acids called fatty acids

Answer 6

Triglycerides

Question 7

triglycerides also called

Answer 7

triacylglycerols

Question 8

Two Types of Triacylglycerols

Answer 8

Simple Triacylglycerols
Mixed Triacylglycerols

Question 9

Three identical fatty acids ar esterified
– Naturally occurring simple triacylglycerols are rare

Answer 9

Simple Triacylglycerols

Question 10

A triester formed from theesterification of
glycerol with more than one kind of fatty acid
– In nature mostly mixed triacylglycerols are found and are
different even from the same source depending on the feed, e.g., corn,
peanut and wheat -fed cows have different triacylglycerols

Answer 10

Mixed Triacylglycerols

Question 11

Amixture of triglycerides containing a high proportion of long-chain, saturated fatty acid

Answer 11

Fat

Question 11

A mixture of triglycerides containing a high proportion of long-chain unsaturated fatty acid or short-chain, saturated fatty acid

Answer 11

Oil

Question 12

base-promoted hydrolysis of fats and oils producing glycerol and
a mixture of fatty acid salts
called soaps

Answer 12

Saponification

Question 12

a lipid
that contains two fatty acids and a
phosphate group esterified to a
glycerol molecule and an alcohol
esterified to the phosphate group.

Answer 12

glycerophospholipid

Question 13

the third major class of lipids which are compounds containing the following
ring system

Answer 13

Steroids

Question 14

Carriers of Cholesterol

Answer 14

Lipoproteins

Question 14

The most abundant steroid in the human body, and the most important, is
cholesterol

Answer 14

Cholesterol

Question 15

oxidation products of cholesterol

Answer 15

Bile salts

Question 16

organic compound that acts as a catalyst for
biochemical reactions

Answer 16

Enzymes

Question 17

composed only of protein (amino acid chains)

Answer 17

Simple enzymes

Question 18

has a nonprotein part (cofactor) in addition to the
protein part (apoenzyme)

Answer 18

Conjugated Enzymes

Question 18

the reactant in an enzyme-catalyzed reaction or the
substance upon which the enzyme acts

Answer 18

Substrate

Question 18

can be a small organic molecule (coenzyme) or an inorganic ion (Zn2+, Fe2+ , etc.)

Answer 18

Cofactors

Question 19

– named based on the type of reaction catalyzed and substrate identity

Answer 19

Nomenclature and Classification of Enzymes

Question 19

catalyze redox reactions

Answer 19

Oxidoreductases

Question 19

catalyze the transfer of a functional group from one molecule to another

Answer 19

Transferases

Question 19

catalyze the addition of two groups to a double bond or the removal of 2 groups from adjacent atoms to create a double bond

Answer 19

Lyases

Question 20

catalyze hydrolysis reaction in which the addition of water molecule to a bond causes the bond to break

Answer 20

Hydrolases

Question 20

catalyze isomerization (rearrangement of atoms) reactions

Answer 20

Isomerases

Question 20

catalyze the joining of two molecules with the help of ATP

Answer 20

Ligases or Synthetases

Question 21

a relatively small part of an enzyme’s structure involved in catalysis

Answer 21

Enzyme Active Site

Question 21

intermediate formed when a substrate binds to the active site

Answer 21

Enzyme-Substrate Complex

Question 22

– active site has a fixed, rigid geometrical conformation

Answer 22

Lock-and-Key Model

Question 22

enzyme will catalyze a particular reaction for only one substrate

Answer 22

Absolute Specificity

Question 22

active site changes shape to accommodate a substrate

Answer 22

Induced-Fit Model

Question 23

enzyme can distinguish between stereoisomers

Answer 23

Stereochemical Specificity

Question 24

involves structurally similar compounds that have the same functional groups

Answer 24

Group Specificity

Question 25

– involves a particular type of bond – the most general

Answer 25

Linkage Specificity

Question 26

Four Factors Affecting Enzyme Activity

Answer 26

1. Temperature 2. pH 3. Substrate Concentration 4. Enzyme Concentration

Question 26

a measure of the rate at which an enzyme converts substrate to products in a biochemical reaction

Answer 26

Enzyme Activity

Question 27

– rate increases as temperature increases, however – when temperature increases beyond “optimum temperature”, enzyme starts to denature and rate drastically decreases

Answer 27

Temperature

Question 28

most enzymes exhibit maximum activity over a very narrow pH range (7.0 – 7.5) – “optimum pH” is where the enzyme exhibits maximum activity

Answer 28

ph

Question 28

– Enzyme activity increases up to a certain substrate concentration and thereafter remains constant – the activity pattern is called a “saturation curve”

Answer 28

Substrate Concentration

Question 29

– number of substrate molecules transformed per minute by one molecule of enzyme under optimum conditions of temperature, pH, and saturation.

Answer 29

Turnover Number

Question 29

– the concentration of substrate in a reaction is much higher than that of the enzyme – greater the enzyme concentration, the greater the reaction rate

Answer 29

. Enzyme Concentration

Question 30

The rates of enzyme-catalyzed reactions can be decreased by a group of substances called inhibitors.

Answer 30

Enzyme Inhibition

Question 31

– a substance that slows or stops the normal catalytic function of an enzyme by binding to it – has three (3) modes: reversible competitive inhibition, reversible non-competitive inhibition, and irreversible inhibition

Answer 31

Enzyme Inhibitor

Question 32

a molecule that sufficiently resembles an enzyme substrate in shape and charge distribution competes with the substrate for occupancy of the enzyme’s active site

Answer 32

Reversible Competitive Inhibition

Question 33

a molecule decreases enzyme activity by binding to a site on an enzyme other than the active site

Answer 33

Reversible Noncompetitive Inhibition

Question 33

– responsible for regulating many cellular processes – an enzyme with two or more protein chains (quaternary structure) and two kinds of binding sites (substrate and regulator)

Answer 33

Allosteric Enzymes

Question 33

– a molecule inactivates enzyme by forming a strong covalent bond to an amino acid side-chain group at the enzyme’s active site – enzyme is permanently deactivated

Answer 33

Irreversible Inhibition

Question 34

a process in which activation or inhibition of the first reaction in a reaction sequence is controlled by a product of the reaction sequence

Answer 34

Feedback Control

Question 34

based on the production of enzymes in an inactive form (zymogens)

Answer 34

Proteolytic Enzymes and Zymogens

Question 35

catalyze the breaking of peptide bonds that maintain the primary structure of a protein

Answer 35

proteolytic enzymes

Question 36

enzyme activity is altered by covalently modifying the structure of the enzyme through attachment of a chemical group to or removal of a chemical group from a particular amino acid within the enzyme’s structure

Answer 36

Covalent Modification of Enzymes