U3A1: 3A enzymes in dna manipulation

Question 1

enzymes

Answer 1

organic catalysts that speed up reactions.

Question 2

explain an enzyme’s active site

Answer 2

each enzyme has an active site complementary to the substrate. when a substrate binds to an active site they form an ‘enzyme substrate complex’, in which the active site undergoes conformational change. the reaction then occurs and the products leave the enzyme.

Question 3

features of enzymes

Answer 3

• reusable
• specific
• reversible (one enzyme can be catabolic and anabolic)
• speed up, not create
• have an active site
• are proteins
• type of catalysts
• act on entire biochemical pathways (catalyse each step)
• end in “-ase”
• above the arrow

Question 4

activation energy

Answer 4

minimum amount of energy needed to energise atoms to a state they can undergo chemical transformation.

Question 5

anabolic reaction

Answer 5

when 2+ smaller molecules combine to form a larger molecule.

Question 6

catabolic reaction

Answer 6

when larger molecules turn into 2+ smaller molecules.

Question 7

DNA polymerase

Answer 7

extends primer to synthesise new DNA by adding more nucleotides to leading and lagging DNA strands.

Question 8

taq polymerase

Answer 8

form of DNA polymerase that is found in hot springs bacteria, and is stable at high temperatures.

Question 9

restriction enzymes (restriction endonuclease)

Answer 9

cuts DNA at a restriction site. these cuts may be sticky (overhanging) or blunt.

Question 10

DNA ligase

Answer 10

repairs small breaks in DNA. joins DNA fragments together by forming phosphodiester bonds between nucleotides via condensation reactions.

Question 11

RNA polymerase

Answer 11

assembles RNA (such as mRNA, tRNA, and rRNA)