D1.1 DNA replication HL

Question 1

DNA Polymerase Directionality

Answer 1

DNA polymerases add nucleotides in the 5ʹ to 3ʹ direction, requiring a template strand oriented 3ʹ to 5ʹ.

Question 2

Leading Strand Replication

Answer 2

Continuous replication along the template strand in the 5ʹ to 3ʹ direction

Question 3

Lagging Strand Replication

Answer 3

Discontinuous replication in short segments (Okazaki fragments), later joined together

Question 4

DNA Primase Function

Answer 4

Synthesizes short RNA primers to initiate DNA replication

Question 5

DNA Polymerase I Role

Answer 5

Replaces RNA primers with DNA nucleotides

Question 6

DNA Polymerase III Function

Answer 6

Main enzyme for DNA chain elongation, adds nucleotides to RNA primers

Question 7

DNA Ligase Role

Answer 7

Joins Okazaki fragments by forming phosphodiester bonds

Question 8

DNA Polymerase III Proofreading

Answer 8

Checks and corrects nucleotide pairing errors during DNA replication

Question 9

Okazaki Fragments

Answer 9

Short DNA segments synthesized on the lagging strand

Question 10

Replication Fork

Answer 10

The area where DNA unwinding and replication occurs

Question 11

RNA Primers

Answer 11

Short sequences allowing DNA polymerases to initiate synthesis

Question 12

Antiparallel Strands

Answer 12

Opposing orientations of the two DNA strands in the double helix

Question 13

Continuous vs. Discontinuous Replication

Answer 13

Continuous on the leading strand, discontinuous on the lagging strand

Question 14

Helicase

Answer 14

Enzyme that unwinds and unzips the DNA double helix

Question 15

Single-Strand Binding Proteins

Answer 15

Stabilize separated DNA strands during replication

Question 16

Complementary Base Pairing

Answer 16

Adenine pairs with Thymine, Cytosine pairs with Guanine

Question 17

Role of Gyrase

Answer 17

Relieves strain caused by unwinding of DNA helix