Lec 5: Molecules, energy and biosynthesis

Question 1

Types of biological molecules

Answer 1

• Lipids
• Carbohydrates
• Proteins
• Nucleic acids

Question 2

diverse group of water insoluble biological molecules

Answer 2

Lipids

Question 3

energy stores

Answer 3

fats

Question 4

major components of membrane

Answer 4

-phospholipids
-sterols

Question 5

are called polyhydroxy aldehydes and ketones

Answer 5

Carbohydrates

Question 6

general formula for carbohydrates

Answer 6

(CH2O)n

Question 7

most complex and most abundant organic molecules

Answer 7

Proteins

Question 8

What does proteins contains

Answer 8

• atleast one carboxyl
• one amino group

Question 9

contents of nucelic acid

Answer 9

• 5 carbon sugar
• phosphate grouo
• nitrogenous base

Question 10

Main classes of Nucleic acids

Answer 10

• DNA (deoxyribonucleic acid)
• RNA (ribonucleic acid)

Question 11

carries coded information, arranged into genes

Answer 11

DNA

Question 12

instrumental in translating the coded message of DNA into amino acid

Answer 12

RNA

Question 13

The process of increasing the rate of reaction with the use of a catalyst

Answer 13

Catalysis

Question 14

any substance that increases rate of reaction

Answer 14

catalyst

Question 15

Catalyst of biochemical reactions

Answer 15

Enzymes

Question 16

How does enzyme increase reaction rate

Answer 16

by means of lowering the energy of activation

Question 17

reactions catalyzed by enzymes are usually
____ to ___times faster than uncatalyzed reactions.

Answer 17

10^3 to 10^17

Question 18

The kinetic energy required to bring the reactants into position to interact

Answer 18

Activation energy/free energy of activation

Question 19

molecule form when enzyme binds with substrate

Answer 19

Enzyme-sustrate complex

Question 20

each enzyme is specific for a certain substrate

Answer 20

Enzyme specificity

Question 21

The enzyme will act on a particular steric or optical isomer

Answer 21

Stereospecificity

Question 22

The enzyme will act on a particular type of chemical bond

Answer 22

Bond specificty

Question 23

highly specific nature of most enzymes arises from the close and complementary fit between enzymes and substrate in a special portion of the enzyme surface

Answer 23

Active site

Question 24

Two models for enzyme action

Answer 24

• Lock-and-key model
• Induced fit model

Question 25

that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit

Answer 25

Induced fit model

Question 26

The active site of an enzyme is structured to fit a specifically shaped substrate

Answer 26

lock-and-key model

Question 27

Mechanism of catalysis by enzymes

Answer 27

- Enzyme activity - Turnover number

Question 28

catalytic potency of an enzyme

Answer 28

Enzyme activity

Question 29

number of reactions catalyzed per second by the enzyme

Answer 29

Turnover number

Question 30

Substrate interacts with the active site of the enzyme, forming an enzyme-substrate complex

Answer 30

Enzymatic reaction

Question 31

How does enzyme accelerate reactions?

Answer 31

- holds substrates in close proximity to one another - form an unstable intermediate - presence of proton donors and acceptors

Question 32

Factors affecting enzyme activity

Answer 32

- Temperature - Reaction rates

Question 33

small organic molecules that act as cofactors

Answer 33

Coenzymes

Question 34

enzyme minus its cofactor; cannot function without its cofactor/coenzyme

Answer 34

Apoenzymes

Question 35

whole enzyme

Answer 35

Haloenzyme

Question 36

Classification of enzyme

Answer 36

- Oxidoreductase - Transferase - Hydrolase - Lyase - Isomerase - Ligase

Question 37

Oxidation-reduction reactions

Answer 37

Oxidoreductase

Question 38

Group transfer

Answer 38

Transferase

Question 39

Hydrolysis reactions

Answer 39

Hydrolase

Question 40

Addition or removal of groups to form double bonds

Answer 40

Lyase

Question 41

Isomerization (intramolecular group transfer)

Answer 41

Isomerase

Question 42

Ligation of two substrate at the expense of ATP hydrolysis

Answer 42

Ligase

Question 43

Example of oxidoreductase

Answer 43

Lactate dehydrogenase

Question 44

Example of transferase

Answer 44

Nucleoside monophosphate kinase

Question 45

Example of Hydrolase

Answer 45

Chymotrypsin

Question 46

Example of lyase

Answer 46

Fumarase

Question 47

Example of Isomerase

Answer 47

Triose phosphate isomerase

Question 48

Example of Ligase

Answer 48

Aminoacyl-tRNA synthease

Question 49

The rate at which an enzymatic reaction proceeds depends on;

Answer 49

- concentrations of substrate, - product - active enzyme

Question 50

used in the living cell as a means of controlling enzymatic reaction

Answer 50

Enzyme inhibition

Question 51

a molecule that binds to an enzyme and blocks its activity

Answer 51

Enzyme inhibitor

Question 52

Two types of enzyme inihibition

Answer 52

- Competitive inhibition - Noncompetitive inihibition

Question 53

substrate molecule is prevented from binding to the active site of an enzyme by a molecule that is very similar in structure to the substrate

Answer 53

competitive inhibition

Question 54

How to reverse competitive inhibition

Answer 54

increasing substrate concentration

Question 55

Caused by molecules that bind to a region(s) of the enzyme outside the active site

Answer 55

noncompetitive inhibition

Question 56

how to reverse noncompetitive inhibition

Answer 56

dilution or removal of inihibitor

Question 57

Regulation of Metabolic Reactions

Answer 57

- Control of enzyme synthesis - Control of enzyme activity

Question 58

enzymes are only synthesized when needed

Answer 58

Control of enzyme synthesis

Question 59

regulated by modulator molecules

Answer 59

Control of enzyme activity

Question 60

alters the tertiary structure of the enzyme thus changing the conformation of the active site.

Answer 60

Allosteric site

Question 61

first enzyme of the sequence that acts as the regulatory enzyme - limits the rate of accumulation of the product by slowing the entire sequence from the beginning

Answer 61

End-product (feedback) inhibition

Question 62

several cat-ion cofactors act as allosteric activators for some enzymes

Answer 62

Enzyme activitation

Question 63

TWO KINDS OF ENERGY-YIELDING Pathways for Animal tissues

Answer 63

1. Aerobic metabolism 2. Anaerobic metabolism

Question 64

food molecules are completely oxidized to carbon dioxide and water by molecular oxygen; energy yield is far greater.

Answer 64

Aerobic respiration

Question 65

food molecules are oxidized incompletely to lactic acid (lactate); absence of oxygen

Answer 65

Anaerobic metabolism