Life sciences code of life- grade 12

Life Sciences Grade 12
DNA: Code of life
(CAPS, 2011:59)

By Danielle Plooy

​"Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism" (Bates, 2025).

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Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries ​

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information for the development and ​ functioning of an organism

Multiple Select

According to your notes and lesson 1 of this unit. Which two scientists discovered the structure of DNA in 1953?

• Francis Crick

• James Watson

• Maurice Wilkins

• Rosalind Franklin

Multiple Choice

Which following facts about the DNA structure is false?

• The DNA molecule is made up of a ladder like structure, called a Double Helix.

• All DNA structures in the body are identical

• A DNA molecule is made up of Nucleotides.

• DNA can be found in the nucleus and are grouped into chromosomes.

Labelling

A DNA molecule is known to have a double helix structure, made up of millions of tiny nucleotides. Complete the structure on the right by adding the proper labels.

Drag labels to their correct position on the image

Sugar phosphate backbone

Base pairs

Guanine

Nitrogeous base

Adenine

Thymine

Cytosine

Match

Nucleotides consist of bases that pair specifically with complementary bases. Match the bases below to the correct base they pair with.

• Guanine (G)

• Thymine (T)

• Cytosine (C)

• Adenine (A)

Cytosine (C)

Adenine (A)

Guanine (G)

Thymine (T)

• Cytosine (C)

• Adenine (A)

• Guanine (G)

• Thymine (T)

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The genetic code has a specific sequence. The bases are arranged in triplets called​

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​ ​ ​ for example: A G G- C T C -A AG -T C C-T A G T C C-G A G -T TC - A G G- A T C

Reorder

Resources for extra learning:

https://bio.libretexts.org/Under_Construction/Cell_and_Molecular_Biology_(Bergtrom)/09%3A_Details_of_DNA_Replication_and_DNA_Repair/9.04%3A_The_Process_of_Replication

As explained by Bergtrom (n.d.) in the article The Process of Replication, DNA replication involves the joining of nucleotide building blocks through repeated dehydration reactions, resulting in the formation of a long DNA strand.

With this knowledge, reorder the steps of DNA replication.

• Unwinding- The enzyme helicase creates a replication fork.

• Priming- Primase adds short RNA primers for synthesis.

• Elongation- DNA polymerase adds new nucleotides.

• Leading and lagging strands are made

• Joining- Ligase seals the fragments together.

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Hotspot

Show which areas on the (gene) DNA are non-coding areas.