AP Bio: Instructor - lead DNA replication

...by the enzyme

• ligase

• primase

• RNA polymerase

• helicase

• DNA polymerase

The leading strand is synthesized​ ​ (a)   towards the ​ (b)   and the lagging strand is synthesized ​ (c)   away from the replication fork.

• continuously
• replication fork
• discontinuously
• rapidly
• slowly
• correctly
• incorrectly

DNA replication begins at a predetermined place in the sequence. The ​ (a)   ​ bonds between the complementary bases are broken and a gap called a “replication bubble” forms. ​ Helicase continues the breaking/​ (b)   of the double helix and creates replication forks. ​ (c)   relaxes the coiled DNA ahead of the replication fork. ​ Once unzipped, the original DNA strands serve as ​ (d)   for the building of the new complementary strands. ​ (e)   DNA strands are synthesized by the enzyme DNA polymerase in the 5’ to 3’ direction.​

• unzipping
• Topoisomerase
• templates
• New
• hydrogen
• sealing
• Ligase
• old

Primase adds a primer on the template strands. ​ (a)   knows to start synthesizing there. ​ DNA polymerase adds new nucleotides continuously in the leading strand and discontinuously in the lagging strand. ​ Leading strand is synthesized in the ​ (b)   direction that the replication fork is opening.​ The lagging strand is synthesized in Okazaki fragments in the ​ (c)   direction that the replication fork is opening. ​ Imagine this as a back-tracking. Since new DNA is synthesized away from the replication fork, there is a sort off jumping backwards once the fork has ​ (d)   up some more. ​ These fragments are eventually bound with the help of ligase (another ​ (e)   ).

• sealing
• Ligase
• old
• DNA polymerase
• same
• opposite
• split
• enzyme
• helicase

The picture below shows an enzyme unwinding and unzipping DNA.

​

​What is the name of this enzyme?

• DNA Helicase

• DNA Ligase

• DNA polyermase

• RNA Polymerase

Which letter in the picture below depicts the lagging strand in DNA replication?

• A

• C

• B

• None of the above

Which letter in the picture below depicts the leading strand in DNA replication?

• A

• C

• B

• None of the above

What is the role of DNA polymerase in DNA replication?

• Unwinds the DNA double helix

• Synthesizes RNA primers

• Adds nucleotides to the growing DNA strand

• Joins Okazaki fragments

Which strand is synthesized continuously during DNA replication?

• Leading strand

• Lagging strand

• Template strand

• Coding strand

What are Okazaki fragments?

• Short DNA sequences synthesized on the leading strand

• Short RNA sequences synthesized on the lagging strand

• Short DNA sequences synthesized on the lagging strand

• Short RNA sequences synthesized on the leading strand