Metabolic Pathways and their Control

Question 1

Active transport

Answer 1

Movement of molecules or ions through a cell membrane from a region of lower concentration to a region of higher concentration.

Question 2

Alternative route

Answer 2

Step(s) in a metabolic pathway that allow the regular steps to be bypassed.

Question 3

Anabolism

Answer 3

Type of metabolic pathway that brings about the biosynthesis of complex molecules and requires energy.

Question 4

Carrier

Answer 4

Type of protein molecule that actively pumps specific ions into and/or out of a cell.

Question 5

Catabolism

Answer 5

Type of metabolic pathway that brings about the breakdown of complex molecules and releases energy.

Question 6

Channel – forming

Answer 6

Type of protein molecule in the cell membrane containing a pore through which specific substances are able to diffuse.

Question 7

Chloroplast

Answer 7

Membrane – bound organelle containing enzymes responsible for the Calvin cycle.

Question 8

Concentration gradient

Answer 8

Difference that exists between two regions resulting in diffusion.

Question 9

Diffusion

Answer 9

Movement of molecules or ions from a region of higher concentration to a region of lower concentration.

Question 10

Metabolism

Answer 10

Sum of all the biochemical reactions occurring within a living organism.

Question 11

Reversible

Answer 11

Step in a metabolic pathway that can operate in both a forward and backward direction.

Question 12

Activation energy

Answer 12

Energy needed to break the chemical bonds in the reactants in a chemical reaction.

Question 13

Active site

Answer 13

Region of an enzyme molecule where the complementary surface of its substrate molecule becomes attached.

Question 14

Affinity

Answer 14

Degree of chemical attraction between reactant molecules.

Question 15

Catalyst

Answer 15

Substance that increases the rate of a chemical reaction and remains unaltered by the reaction.

Question 16

End product

Answer 16

Substance formed as a result of an enzyme acting on its substrate.

Question 17

Enzyme

Answer 17

Protein made by living cells that acts as a biological catalyst.

Question 18

Induced fit

Answer 18

State of close molecular contact resulting from change in shape of an enzyme’s active site to accommodate its substrate.

Question 19

Orientation

Answer 19

Way in which molecules of two reactants are held together as determined shape of the enzyme’s active site.

Question 20

Reaction rate

Answer 20

Amount of chemical change that occurs per unit of time.

Question 21

Specificity

Answer 21

Complementary relationship of a molecular structure allowing an enzyme to combine with one type of substrate only.

Question 22

Substrate

Answer 22

Substance upon which an enzyme acts, resulting in the formation of an end product.

Question 23

Transition

Answer 23

State of reactant molecules that have absorbed enough energy to break and allow the reaction to occur.

Question 24

Allosteric site

Answer 24

Non-active location on an enzyme molecule to which an inhibitor or an activator may become attached.

Question 25

Competitive

Answer 25

Type of inhibitor with a molecular structure similar to an enzyme’s substrate enabling it to become attached to the enzyme’s active site.

Question 26

End – product inhibition

Answer 26

Process by which a metabolite at a later stage in a pathway builds up and prevents the activity of an enzyme controlling an earlier stage.

Question 27

Inhibitor

Answer 27

Regulatory molecule that halts or decreases the rate of an enzyme – controlled reaction.

Question 28

Non– competitive

Answer 28

Type of inhibitor that becomes attached to a non-active site on an enzyme and changes the enzyme’s molecular shape.