DNA replication


DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA replication takes place during interphase of the cell cycle.

  • The DNA double helix unwinds
  • Weak hydrogen bonds between nitrogenous bases break and the two DNA strands unzipBoth DNA strands serves as templates
  • Free nucleotides in the nucleoplasm are used to build a complementary DNA strand onto each of the original DNA strands (A to T and G to C)
  • This results in two identical DNA molecules. Each molecule consists of one original and one new strand


For futher reading on DNA replication please visit https://en.wikipedia.org/wiki/DNA_replication


For todays Task please complete the following  worksheet


Name:______________________ _______________________Date_______


DNA Replication exercise


Directions: Below are the 3 steps in DNA replication. Follow the directions for each step and then answer the questions below.


  1. -What is happening to the DNA molecule in the figure? (Explain the first step in DNA replication)









  1. -What happens to the DNA molecule during the second step of DNA replication?









  1. -What happens during the third step of DNA replication?








How DNA Is Copied

  1. What does it mean that the two strands of DNA are complementary? ______________



  1. What is DNA replication?___________________________________________________________________________________________________
  2. ______________________________________________________________________________________________________________________________________________________________________________________________________
  3. Using your notes, book and place the steps of DNA replication in the correct order.

____    a. The enzyme DNA polymerase moves along the exposed strands and adds

complementary nucleotides to each nucleotide in each existing strand.

____     b. The DNA double helix breaks or unzips down the middle between the base pairs.

____    c. A complementary strand is created for each of the two strands of the original double helix.

____    d. Two new identical DNA molecules have been produced.

  1. (True or False)  The process of DNA replication results in a copy of the original DNA molecule.
  2. (True or False)  DNA does not have to break apart to be copied.
  3. (True or False) After DNA replication is complete, there are two new DNA molecules; one molecule has both of the original strands and one molecule has two new strands of DNA.
  4. Where does DNA replication happen?________________________________________


  1. When does DNA replication happen?________________________________________
  2. Below are DNA strands.  Make the complementary DNA strand:

Original Strand: A T G C A A A T T G C T C A C C G G G G A T C A G C A C C G G

Complementary Strand:  _____________________________________________________

Original Strand: A G G G G A T C A G C A C C G G A T T T C A T G A G C C C T A

Complementary Strand: ____________________________________________________

Original Strand: A A G T A C G A T C G A T G C A C A T G C A T G G C T A C G C

Complementary Strand: ______________________________________________________


  • Please refer to Your Textbook Page 20-22 and study carefully the steps of DNA replication. 
  • Revise the Notes that we covered in the Classroom
  • Use the video below for more revision 



Make sure you read your rubric carefully before answering your worksheet. 

Criteria  4 3 2 1 0

Completion of blank


Learner filled all the blank spaces learner Have some blank spacess learner filled few blank spaces learner didn't fill blank spaces s indicated  learner didn't Fill any blank spaces
Knowledge for Steps of DNA replication  learner successfully shows knowledge For steps of DNA replication  learner shows knowledge for DNA replication steps  learner does not shows full knowledge of DNA replication Steps learner have the least knowledge for DNA replication Steps learner Have no knowledge for DNA replication steps
Making of complementary strand of DNA learner Correctly made the Complementary Strand need learner knowledge for complementary Strand is acceptable.  learner made the Complementary Strand but the Nitrogenous Base pairs were incorrect order.  complementary strand made by the learner was Totally incorrect.  learner didn't made complementary Strand. 
Usage of Textbook, Notes and Video Textbook, Notes and Video Were correctly used in the worksheet  learner used Notes, Textbook and Video to complete Worksheet  learner didn't used all the resources required to complete Worksheet  Learner used least resources to complete Worksheet  No resources were used



Emphasize important points of the lesson. The completion of your worksheet will be used in the continuation of this topic. for more queries, you have my email also if you do not have it please find it on the teachers page. Thank you


You tube videos

Wikipedia Notes and photos


Teacher Page

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