Unit 1 KA6 - Metabolic Pathways

Question 1

what is an enzyme?

Answer 1

a biological catalyst made up of protein which speeds up chemical reactions.

Question 2

which factors affect enzyme activity?

Answer 2

temperature, pH, presence of substrates, presence of inhibitors, end-product concentration.

Question 3

what is a metabolic pathway?

Answer 3

a sequence of enzyme-controlled reactions where the products of one reaction can influence the next.

Question 4

what are the two types of metabolic pathways?

Answer 4

catabolic and anabolic.

Question 5

…………. pathways are the breakdown of ………. molecules to ………… ones.

Answer 5

catabolic, complex, simpler.

Question 6

……………pathways requires energy and is a …………..process

Answer 6

anabolic, biosynthetic.

Question 7

anabolic pathways are catalysed by the enzyme…………..

Answer 7

DNA polymerase.

Question 8

catabolic pathways are catalysed by the enzyme………..

Answer 8

glycogen phosphorylase.

Question 9

what is meant by the active site of an enzyme?

Answer 9

a hollow on the enzyme’s surface which has a particular shape determined by the chemical structure of protein and the bonding between amino acids (caused by the amino acid sequence).

Question 10

the role of the active site of an enzyme is to ……… the activation ……….. needed for the reaction to occur, …………the reactants, releases………. after the reaction.

Answer 10

lower, energy, orientates, releases.

Question 11

what is meant by induced fit?

Answer 11

when a molecule of substrate enters the active site and the shape of the enzyme molecule and active site changes slightly, making the active site fit very closely around the substrate molecule.

Question 12

a multi-enzyme complex is when several different………. are arranged in a ………….., promoting a series of …………. steps in a metabolic…………… and ensures that they occur in a specific………….

Answer 12

enzymes, membrane, related, pathway, order.

Question 13

many reactions in the cell are reversible and can go either way depending on …………….

Answer 13

the concentration of substrate and products.

Question 14

the …………. of a substrate/……. of a product will drive a ……….. of reactions in a …………………

Answer 14

presence, removal, sequence, particular direction.

Question 15

what is an inhibitor?

Answer 15

a substance that decreases the rate of an enzyme-controlled reaction.

Question 16

what are the three types of inhibition?

Answer 16

competitive, non-competitive, and end product (negative feedback).

Question 17

describe how a competitive inhibitor decreases the rate of an enzyme-controlled reaction.

Answer 17

they are a similar shape to the substrate so bind with the active site and block it from the substrate by competing with the substrate for the active site.

Question 18

competitive inhibition can be………….. by ………………. the substrate ……………..

Answer 18

reversed, increasing, concentration.

Question 19

describe how a non-competitive inhibitor decreases the rate of an enzyme-controlled reaction.

Answer 19

they bind to the enzyme, not at the active site.

this changes the shape of the active site so the substrate no longer fits.

Question 20

end-product (…………….) inhibition is when the ……………… in the metabolic …………… reaches a ……….. condition.
the ……….. product then ……… an …………… blocking the pathway and …………… further …………… of the ……………………

Answer 20

negative feedback, end product, pathway, critical, end, inhibits, earlier enzyme, preventing, synthesis, end product.