chapter 4- Enzymes

Question 1

enzymes are biological catalysts,
what biological molecule are enzymes

Answer 1

-globular proteins

Question 2

what is a feature of an enzyme

Answer 2

-an active site which is specific and unique in its shape due to the specific folding and bonding in the tertiary structure of the protein.

Question 3

tertiary structure definition

Answer 3

the specific overall 3d shape of a protein determined by r group properties and r group interactions.

Question 4

what does the specific shape of the active site mean for the enzyme

Answer 4

enzymes can only attach to substrates that are complementary to the shape of the active site of the enzyme

Question 5

what are intracellular enzymes

Answer 5

catalyse reactions that take place inside of cells
example: catalase

Question 6

what are extracellular enzymes

Answer 6

catalyse reactions that take place outside of cells
examples: amylase and trypsin

Question 7

trypsin definition

Answer 7

an extracellular enzyme that hydrolyses proteins into polypeptide chains and eventually amino acids.
found in small intestines

Question 8

catalase definition

Answer 8

intracellular enzyme that catalyses the breakdown of h202 hydrogen peroxide into oxygen and water in liver cells.

Question 9

how do enzymes catalyse a reaction

Answer 9

they lower the activation energy of the reaction

Question 10

describe the lock and key model

Answer 10

suggests enzyme is like a lock and substrate is like a key that fits into it due to the enzymes specific tertiary structure resulting in its complementary shape

Question 11

how does the lock and key model explain the activation energy being lowered

Answer 11

the enzyme active site is a fixed shape, due to random collision, the substrate can collide and attach onto the active site of the enzyme forming an enzyme substrate complex. the charged groups within the active site are thought to distort the substrate lowering the activation energy.

Question 12

what is the induced fit hypothesis

Answer 12

induced fit hypothesis suggests that when the enzyme is induced (changes shape) to mould around the substrate, this induces changes in the enzyme’s tertiary structure that strengthen binding and so puts a strain on the substrate molecule which weakens bonds in the substrate, lowering the activation energy

Question 13

list the four factors that effect the rate of enzyme activity

Answer 13

-temperature
-Ph
- enzyme concentration
-substrate concentration