Worksheet 1 DNA REPLICATION Flashcards
When should DNA be replicated?
Any time the cell needs to divide.
What life events would include DNA replication?
Growth, wound healing, regeneration, gamete production
Which enzyme acts first in DNA replication?
A. Helicase
B. Primase
C. Polymerase
D. Ligase
A. Helicase
Which enzyme(s) add(s) new DNA nucleotides to an existing strand? (Select all that apply.)
A. Primase
B. Ligase
C. Polymerase
D. Helicase
C. Polymerase
What is the difference between the leading strand and the lagging strand?
The leading strand goes in the 3’ to 5’ orientation, so it can be copied in a linear line. The lagging strand is in the 5’ to 3’ direction, so it must be copied in sections (in the opposite orientation) and those sections ‘glued’ together. Remember that DNA is always synthesized in the 5’ to 3’ direction.
TRUE or FALSE: Replication of the leading and lagging strands requires different enzymes.
FALSE
Why are there no Okazaki fragments on the leading strand?
Okazaki fragments are formed on the lagging strand so DNA can be synthesized in the essential 5’ to 3’ manner on the lagging strand.
Why is it important to replicate DNA without errors?
Because the sequence of DNA is what makes it do what it does.
What might happen if there were errors in DNA replication.
A mutation means a sequence change: in a somatic cell, this could lead to cancer;
What happens to the original template DNA after a round of replication?
It is paired with a newly synthesized DNA strand
Instead of Thymine, RNA has
Uracil
Draw a single nucleotide, labeling the phosphate, in the box to the right:
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Draw and label a double-stranded segment of DNA with four nucleotides (arranged in two base pairs)
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Draw and label a nucleosome