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SingaporeBiotechnology

DNA and Genetic Material

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Before a cell divides, how does it make a perfect copy of all its DNA?

Describe how DNA is replicated, including the role of the template strand and complementary base pairing
A focused answer to the O-Level outcome on DNA replication. Unwinding the helix, using each strand as a template, complementary base pairing, and why replication is accurate.
8 min answer →

How can you get the DNA out of living cells and actually see it, using everyday materials?

Describe how DNA can be extracted from cells in the laboratory and explain the purpose of each step
A focused answer to the O-Level outcome on DNA extraction. Breaking open cells, removing proteins, precipitating DNA with cold alcohol, and the reason for each step.
8 min answer →

How does the order of bases in a gene end up deciding what protein a cell makes?

Explain how a gene codes for a protein through transcription and translation using the genetic code
A focused answer to the O-Level outcome on gene expression. What a gene is, the triplet code, transcription to mRNA, translation to protein, and why the base order matters.
9 min answer →

Once you have a gene, how do you actually carry it into a cell so the cell will use it?

Describe plasmids and other vectors and explain how they are used to carry genes into host cells
A focused answer to the O-Level outcome on vectors. What plasmids are, why they make good vectors, other vectors such as viruses, and how a gene is carried into a host cell.
8 min answer →

What is DNA actually made of, and how does its shape let it store the instructions for life?

Describe the structure of DNA as a double helix of nucleotides with complementary base pairing
A focused answer to the O-Level outcome on DNA structure. Nucleotides, the double helix, the four bases, complementary base pairing, and why the structure suits storing information.
9 min answer →