enzymes structure + function

Question 1

what kinds of proteins are enzymes

Answer 1

globular proteins

Question 2

what kinds of proteins do enzymes have

Answer 2

mostly quaternary (some tertiary)

Question 3

define catabolic reactions

Answer 3

break down big molecules into small molecules

Question 4

define anabolic reactions

Answer 4

combine smaller molecules into larger molecules

Question 5

what is induced fit

Answer 5

enzyme changes shape in order to fit substrate

Question 6

define enzyme

Answer 6

biological enzymes used to speed up metabolic reactions

Question 7

what does an enzyme inhibitor do

Answer 7

interfere with functioning of the active site of an enzyme

Question 8

what do competitive inhibitors do

Answer 8

compete with substrate to occupy active site of enzyme (not permanent)

Question 9

what do non-competitive inhibitors do

Answer 9

alter the shape of the enzymes active site so enzyme cant function (permanent)

Question 10

define metabolic pathway

Answer 10

series of reactions in which each step is catalysed by an enzyme

Question 11

how do enzyme properties relate to their tertiary structure

Answer 11

each different enzyme has a different tertiary structure and therefore active site. only 1 substrate can fit, so only one reaction can be catalysed

Question 12

what is an extracellular enzyme

Answer 12

produced and secreted by cells to catalyse reactions outside of cells

Question 13

how does substrate concentration affect the rate of reaction

Answer 13

more substrate molecules, more collisions, more actve sites used up.
increases rate of reaction up to a point

Question 14

how do enzymes lower their activation energy in anabolic reactions

Answer 14

enzymes hold 2 substrate molecules close together, reducing any repulsion between the molecules so they bond more easily

Question 15

how does enzyme concentration affect the rate of reaction

Answer 15

more enzyme molecules, more active sites, more likely for collisions to occur. increasing rate of reaction

Question 16

what is an intracellular enzyme

Answer 16

catalyse reactions inside cells

Question 17

what happens if substrate concentration is limited

Answer 17

increasing enzyme conc would have no further affect, substrate conc would be limiting factor

Question 18

define enzyme

Answer 18

biological catalyst that speeds up chemical reactions by reducing the activation energy

Question 19

why are enzymes highly specific

Answer 19

tertiary structure means only one complimentary substrate will fit into the active site

Question 20

in relation to enzymes, what is saturation point

Answer 20

all active sites are full and adding more substrate s would have no further effect

Question 21

why can gene mutation result in an enzyme not catalysing a reaction

Answer 21

changed base sequence of a gene, changing primary structure of a protein, so different R groups, and different binding between them, folding changes, 3D structure changes.
therefeore active site changes and an enzyme substrate complex cant be made

Question 22

how do enzymes lower the activation energy in catabolic reactions

Answer 22

fitting into the active site puts a strain on the bonds in the substrate so the substrate molecules break up more easily

Question 23

describe the lock and key theory

Answer 23

single molecule w a shape that has a complimentary fit in the active site. substrate forms temporary bonds with the amino acids in the active site forming n enzyme substrate complex

Question 24

describe induced fit theory

Answer 24

enzymes are specific so only bond to one substance. complementary substrate enters active site and causes active site to change shape so it fits more closely around substrate