what are enzymes

Question 1

define active site

Answer 1

indented area on the surface of an enzyme molecule with a shape that is complementary to the shape of the substrate molecule

Question 2

define catalyst

Answer 2

chemical that speeds up the rate of reaction without being used up at the end of the reaction

Question 3

define extracellular

Answer 3

outside the cell

Question 4

define intracellular

Answer 4

inside the cell

Question 5

define metabolic reactions

Answer 5

the chemical reactions that take place inside living cells or organism

Question 6

define metabolism

Answer 6

the sum of all the different reactions and reaction pathways happening in a cell or organism and can only happen as a result of enzymes

Question 7

define product

Answer 7

molecule produced from susbtrate molecules by an enzyme catalysed reaction

Question 8

define substrate

Answer 8

molecule that is altered by an enzyme catalysed reaction

Question 9

what are enzymes

Answer 9

• globular proteins
• biological catalysts
• speed metabolic reactions in living organisms

Question 10

why are enzymes used to speed up rate of reactions

Answer 10

normally to speed up a reaction a high temperature and pressure would be required which is not possible in living cells as an extemely high temperature can denature other proteins in the body

Question 11

in which conditions can enzymes speed up rate of reactions

Answer 11

• low temperature
• neutral pH
• normal pressure

Question 12

what is special about catalysts

Answer 12

a small number of catalyst can catalyse the conversion of a large number of substrate molecules into product molecules

Question 13

what is turnover number

Answer 13

the number of reactions an enzyme molecule can catalyse per second

Question 14

why are enzymes more specific than chemical catalysts

Answer 14

they don’t produce unwanted by-products
the cells in which they are made or act can regulate their production and activity to fit the needs of the cell or organism at the time

Question 15

describe enzymes

Answer 15

they are globular prtoeins with hydrophillic R groups faced towards the exterior of the molecule making them soluble.

Question 16

what does bonding of a protein determine

Answer 16

the proteins shape

Question 17

what does the shape of the protein determine

Answer 17

its function

Question 18

where do enzymes get help from to catalyse certain reactions

Answer 18

cofactors

Question 19

where are instructions for making enzymes encoded

Answer 19

in genes

Question 20

what happens if the gene coding for an enzyme has a mutation

Answer 20

it alters the sequence of amino acids in the protein which may alter the enzymes tertiary structure and prevent it from functioning

Question 21

how does a metabolic disorder arise

Answer 21

if an enzyme that catalyses a metabolic reaction is deficient

Question 22

which structural components of organisms do enzymes catalyse the formation of

Answer 22

• collagen in bone
• cartilage
• blood vessel walls
• joints and connective tissue

Question 23

what do genetic disorders cause

Answer 23

malformation of connective tissue (painful)

Question 24

what is the specific part of the enzyme molecule called

Answer 24

the active site

Question 25

what does the active site consist of

Answer 25

often about 6-10 amino acids

Question 26

why is the tertiary structure of the enzyme important

Answer 26

the shape of the active site has to be complementary to the shape of the substrate

Question 27

why is each enzyme highly specific in its function

Answer 27

it can only catalyse a reaction involving the particular type of substrate molecule that fits in its active site

Question 28

what can alter the shape of an active site and its ability to catalyse a reaction

Answer 28

changes in temperature and pH as these affect the bonds that hold proteins in their tertiary structure

Question 29

name the two types of metabolic reactions

Answer 29

catabolic and anabolic reactions

Question 30

what are anabolic reactions

Answer 30

a reaction that builds larger molecules from smaller ones. they require energy and their purpose is to catalyse reactions required for growth, repair and storage

Question 31

give example of anabolic reactions

Answer 31

protein synthesis DNA replication photosynthesis

Question 32

what are catabolic reactions

Answer 32

reaction that breaks down larger molecules into smaller ones. energy is release. its purpose is to produce energy and recycle cellular components

Question 33

give examples of catabolic reactions

Answer 33

cellular respiration digestion of food glycolysis

Question 34

what are anabolic and catabolic reactions catalysed by

Answer 34

enzymes

Question 35

at which point can enzymes increase the rate of reaction

Answer 35

a certain point called the Vmax

Question 36

what is Vmax

Answer 36

maximum initial velocity or rate of the enzyme catalysed reaction

Question 37

which enzyme functions inside cells

Answer 37

intracellular

Question 38

which reactions involve intracellular enzymes

Answer 38

- respiration - photosynthesis - glycogen synthesis (digestion inside liver and muscle cells) - protein synthesis

Question 39

give an example of an intracellular enzyme

Answer 39

catalase

Question 40

which enzyme functions outside of cells

Answer 40

extracellular enzymes

Question 41

which reactions use extracellular enzymes

Answer 41

- reactions in the human digestive system - decomposition of organisms (bacteria and fungi release enzymes)

Question 42

give example of an extracellular enzyme

Answer 42

maltase and amylase

Question 43

what is the function of catalase

Answer 43

it breaks hydrogen peroxide into water and oxygen to prevent it accumulating

Question 44

what is hydrogen peroxide

Answer 44

a toxic product of many metabolic pathways

Question 45

where is catalase found

Answer 45

in animal and plant tissues

Question 46

where are most substrates obtained

Answer 46

supplied by nutrients in the diet in the form of polymers

Question 47

why do large molecules need to be broken down first

Answer 47

large molecules cannot enter cells directly through the membrane

Question 48

how are large molecules broken down

Answer 48

enzymes are released from cells to break down the nutrient molecules into smaller molecules during digestion

Question 49

what relies on extracellular enzymes

Answer 49

bacteria which release enzymes to break down larger molecules to smaller molecules which are absorbed by the cells.

Question 50

why do large molecules in the digestive system have to be digested

Answer 50

so smaller molecules can be absorbed in the bloodstream and then transported around the body to be used as substrates in cellular enzymes

Question 51

where does digestion of starch occur

Answer 51

begins in the mouth and continues in the small intestine

Question 52

which two enzymes help digest starch

Answer 52

amylase and maltase

Question 53

what is important about amylase and maltase

Answer 53

each enzyme only catalyses one specific reaction

Question 54

how is starch (polysaccharide) broken into maltose (disaccharide)

Answer 54

broken down by amylase

Question 55

where is amylase produced

Answer 55

in salivary glands and pancreas

Question 56

where is amylase released

Answer 56

in saliva into the mouth and in pancreatic juice down into the small intestine

Question 57

how is maltose (disaccharide) broken down into glucose (monosaccharide)

Answer 57

broken down by maltase

Question 58

where is maltase present

Answer 58

in the small intestine

Question 59

what is important about glucose

Answer 59

it is small enough to be absorbed by cells lining the digestive system and then absorbed into the bloodstream