SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

BIOLOGY, M5 2022 HSC 28b

Describe the process of DNA replication.   (3 marks)

Show Answers Only
  1. DNA helicase ‘unwinds’ DNA by breaking hydrogen bonds between the bases.
  2. Binding proteins are added to each strand to prevent them reattaching. 
  3. RNA primase adds RNA primers which act as a promoter region for DNA polymerase.
  4. DNA polymerase adds complementary nucleotides in the 5′ to 3′ direction of each strand.
  5. Exonuclease removes RNA primers, and DNA polymerase adds complementary nucleotides.
  6. DNA ligase reattaches sections together.

 
→ This produces 2 identical DNA molecules, which are also identical to the original.

Show Worked Solution
  1. DNA helicase ‘unwinds’ DNA by breaking hydrogen bonds between the bases.
  2. Binding proteins are added to each strand to prevent them reattaching. 
  3. RNA primate adds RNA primers which act as a promoter region for DNA polymerase.
  4. DNA polymerase adds complementary nucleotides in the 5′ to 3′ direction of each strand.
  5. Exonuclease removes RNA primers, and DNA polymerase adds complementary nucleotides.
  6. DNA ligase reattaches sections together.

 
→ This produces 2 identical DNA molecules, which are also identical to the original.


♦ Mean mark 47%.

BIOLOGY, M5 2022 HSC 28a

Soon after the discovery of the structure of DNA, scientists began investigating how DNA replicated. Three models were proposed.
 

Identify which of the models above is currently accepted.   (1 mark)

Show Answers Only

→ Model 2 is correct.

→ Each replicated copy contains 1 original strand and 1 new strand.

Show Worked Solution

→ Model 2 is correct.

→ Each replicated copy contains 1 original strand and 1 new strand.