TUTORME
LS
40
40
BIOLOGY
TOPIC DNA – THE CODE OF LIFE
ACTIVITIES WITH
ANNOTATED MARKING
GUIDELINES
This pack is designed to support parents, learners, teachers, and tutors
with high-quality materials that make studying easier and more effective.
,DNA – THE CODE OF LIFE
• Two types of nucleic acid → Deoxyribonucleic acid (DNA) and
Ribonucleic acid (RNA)
• The nucleus of a cell is made up of four basic parts:
o Nuclear membrane – double and continuous with the
endoplasmic reticulum. Contains pores on its wall
o Nucleoplasm – contains free nucleotides
o Nucleolus – manufactures and contains ribosomal RNA (rRNA)
o Chromatin network – contains DNA. Unwinds to form
chromosomes
Diagram illustrating the Nucleus
Activity 1
The diagram below illustrates an organelle.
1. Write the LETTER and NAME of the part that:
a) unwinds to form chromosomes. (2)
b) contains the nucleotides. (2)
2. State TWO functions of part labelled A. (2)
(6)
2
© 2025 Tutorme LS. All rights reserved.
,Structure of nucleic acids
• Nucleic acids are made up of a number of smaller units (monomers) =
NUCLEOTIDES
• Nucleotide is made up of:
o Nitrogenous base (NB)
o Pentose sugar portion (S) – deoxyribose in DNA; ribose in RNA
o Phosphate portion (P)
Diagram illustrating the structure of a nucleotide
DNA (Deoxyribonucleic Acid)
Location of DNA
• Nuclear DNA
o Found within the nucleus
o Together with protein make chromosomes, which make up the
chromatin network
o Nuclear DNA + protein → chromosomes → chromatin network
• Extra-nuclear DNA
o Found outside the nucleus
o Chloroplastic DNA – within the chloroplast
o Mitochondrial DNA (mtDNA) – within the mitochondria →
important in helping trace our ancestor
3
© 2025 Tutorme LS. All rights reserved.
, Diagram illustrating the location and composition of a chromosome
Acknowledgement: The University of Waikato Te Whare o Wãnanga o Waikato/ www.sciencelearn.org.nz
History of the Discovery of the DNA Molecule
• In the 1940s, biochemist, Erwin Chargaff came to the
conclusion that DNA is made up of four different types of of
nitrogenous bases (Adenine, Thymine, Guanine,
and Cytosine).
o Irrespective of the species, the number of
adenine was always = the number of thymine
o the number of cytosine was always = Photo of Erwin Chargaff
the number of guanine
Source: Wikipedia
• Two English biophysicists, Maurice H. Wilkins and
Rosalind Franklin, studied the structure of DNA using X-
rays.
o They realized that if DNA could be extracted and
made into a concentrated viscous solution, it
could be separated into fibres that, under the
right conditions, were like crystals through Photo of Maurice Wilkins
with a model of a DNA
which an X-ray beam could be passed to produce molecule, 1962.
an X-ray pattern on photographic film. Source: Britannica
o Franklin’s photo was named photo 51 → showed
the three dimensional structure of DNA indicating
that DNA was helical in nature and had a regular
shape
Photo of Rosalind Franklin
4 Source: Donaldson
Collection/Getty Images
© 2025 Tutorme LS. All rights reserved.
LS
40
40
BIOLOGY
TOPIC DNA – THE CODE OF LIFE
ACTIVITIES WITH
ANNOTATED MARKING
GUIDELINES
This pack is designed to support parents, learners, teachers, and tutors
with high-quality materials that make studying easier and more effective.
,DNA – THE CODE OF LIFE
• Two types of nucleic acid → Deoxyribonucleic acid (DNA) and
Ribonucleic acid (RNA)
• The nucleus of a cell is made up of four basic parts:
o Nuclear membrane – double and continuous with the
endoplasmic reticulum. Contains pores on its wall
o Nucleoplasm – contains free nucleotides
o Nucleolus – manufactures and contains ribosomal RNA (rRNA)
o Chromatin network – contains DNA. Unwinds to form
chromosomes
Diagram illustrating the Nucleus
Activity 1
The diagram below illustrates an organelle.
1. Write the LETTER and NAME of the part that:
a) unwinds to form chromosomes. (2)
b) contains the nucleotides. (2)
2. State TWO functions of part labelled A. (2)
(6)
2
© 2025 Tutorme LS. All rights reserved.
,Structure of nucleic acids
• Nucleic acids are made up of a number of smaller units (monomers) =
NUCLEOTIDES
• Nucleotide is made up of:
o Nitrogenous base (NB)
o Pentose sugar portion (S) – deoxyribose in DNA; ribose in RNA
o Phosphate portion (P)
Diagram illustrating the structure of a nucleotide
DNA (Deoxyribonucleic Acid)
Location of DNA
• Nuclear DNA
o Found within the nucleus
o Together with protein make chromosomes, which make up the
chromatin network
o Nuclear DNA + protein → chromosomes → chromatin network
• Extra-nuclear DNA
o Found outside the nucleus
o Chloroplastic DNA – within the chloroplast
o Mitochondrial DNA (mtDNA) – within the mitochondria →
important in helping trace our ancestor
3
© 2025 Tutorme LS. All rights reserved.
, Diagram illustrating the location and composition of a chromosome
Acknowledgement: The University of Waikato Te Whare o Wãnanga o Waikato/ www.sciencelearn.org.nz
History of the Discovery of the DNA Molecule
• In the 1940s, biochemist, Erwin Chargaff came to the
conclusion that DNA is made up of four different types of of
nitrogenous bases (Adenine, Thymine, Guanine,
and Cytosine).
o Irrespective of the species, the number of
adenine was always = the number of thymine
o the number of cytosine was always = Photo of Erwin Chargaff
the number of guanine
Source: Wikipedia
• Two English biophysicists, Maurice H. Wilkins and
Rosalind Franklin, studied the structure of DNA using X-
rays.
o They realized that if DNA could be extracted and
made into a concentrated viscous solution, it
could be separated into fibres that, under the
right conditions, were like crystals through Photo of Maurice Wilkins
with a model of a DNA
which an X-ray beam could be passed to produce molecule, 1962.
an X-ray pattern on photographic film. Source: Britannica
o Franklin’s photo was named photo 51 → showed
the three dimensional structure of DNA indicating
that DNA was helical in nature and had a regular
shape
Photo of Rosalind Franklin
4 Source: Donaldson
Collection/Getty Images
© 2025 Tutorme LS. All rights reserved.
