Question

dna replication
animation learning module: dna replication
read the overview below and complete the activities that follow.
this animation learning module is designed to increase your understanding of basic dna structure. first, you will answer basic questions related to this topic. then, you will actively engage with an animation by answering questions as you watch. finally, you will be given some follow - up concept check questions to make sure you understand the concept fully.
concept check #2

1. dna polymerase _.

synthesizes both new strands continuously
can only add nucleotides in a certain direction
unwinds the helix and separates the two strands
\stitches\ the okazaki fragments together

1. on one of the strands of bacterial dna, the new complementary strand is synthesized discontinuously into small pieces of dna called _.

spliceosomes
okazaki fragments
introns
ladding fragments

1. one bacterial chromosome replicates to become two chromosomes with _.

each made of one strand of dna from the original chromosome and one newly synthesized strand
each made of alternating 1,000 bp stretches of original and newly synthesized dna
each made entirely of newly synthesized dna after the original is enzymatically degraded
one of which contains the original dna and one of which is made entirely of newly synthesized dna

Explanation:

1. DNA polymerase can only add nucleotides in a certain direction (the 5' to 3' direction). It does not synthesize both strands continuously (one is the leading strand and one is the lagging strand). Helicase unwinds the helix and separates the two strands. DNA ligase "stitches" the Okazaki fragments together.
2. During DNA replication, on the lagging strand (one of the strands in bacterial DNA), the new complementary strand is synthesized discontinuously into small pieces called Okazaki fragments. Spliceosomes are involved in RNA splicing. Introns are non - coding regions in eukaryotic genes. There is no such thing as ladding fragments in DNA replication.
3. Bacterial chromosome replication follows a semi - conservative model. Each new chromosome is made of one strand of DNA from the original chromosome and one newly synthesized strand. It is not made of alternating stretches, entirely new DNA (after degradation of the original), or one original and one entirely new.

Answer:

1. can only add nucleotides in a certain direction
2. Okazaki fragments
3. each made of one strand of DNA from the original chromosome and one newly synthesized strand