A1.2.1—DNA as genetic material
DNA acts as the hereditary material in living organisms, carrying genetic information in chromosomes and some organelles while RNA genomes occur only in viruses.
- Syllabus
- First assessment 2025
- Objective
- A1.2.1
- Level
- HL
Exam analysis
Chance of appearing2%of analysed past papers
Latest appearanceNovember 2023
Most common paperPaper2
Typical marks1
Common command terms
- State
Recent exam appearances
November 2023Paper2 HL · TZ23(a)[ 1 ]A1.2.1—DNA as genetic material
November 2023Paper2 HL · TZ13(a)[ 1 ]A1.2.1—DNA as genetic material
Practice this objective
Coverage 2023–2023 · Updated 14 Jul 2026
DNA Is the Genetic Material of Living Organisms
DNA is the genetic material of all living organisms: its base sequence stores information that can be copied and inherited.
DNA occurs in chromosomes and also as smaller genomes in mitochondria and chloroplasts. Copying DNA allows cells and offspring to receive genetic information.
Apply the rule to living organisms, then handle the exception carefully: some viruses use RNA as genetic material, but viruses are not classified as living organisms.
A plant cell contains DNA in its nuclear chromosomes, mitochondria and chloroplasts; all of these DNA molecules carry heritable information.
The existence of RNA viruses does not contradict the statement about all living organisms, because viruses are not regarded as living organisms in this syllabus.
DNA as genetic material
Assessment in practice
1 marksHow it is assessed
This objective is assessed through multiple choice, commonly using State.
Command terms
State
What earns marks
Build the answer around this relationship: DNA as genetic material should be described using precise molecular vocabulary.
Representative question
Question 1
The Human Genome Project completed the sequencing of the human genome by the year 2003. Which could have been a source of the entire genome in humans?
A
The contents of a red blood cell
B
The nucleus and mitochondria of a skin cell
C
The nucleus and acrosome of a sperm cell
D
The nucleus and ribosomes of any somatic cell
Retrieve The Core Rules
The core chain is: nucleotides have three parts; condensation builds the sugar-phosphate backbone; base order stores information; complementary pairing lets DNA copy and express that information.
- Nucleotide parts: phosphate, pentose sugar, nitrogenous base.
- Polymer rule: condensation forms a sugar-phosphate backbone.
- Code rule: base order stores information and triplet codons specify amino acids.
- Pairing rule: A-T or A-U, and C-G, enables replication and gene expression.
- DNA/RNA contrast: DNA uses deoxyribose/T and is usually double-stranded; RNA uses ribose/U and is usually single-stranded.
Concept essentials
- DNA as genetic material should be described using precise molecular vocabulary.
- Structure and information must be kept separate: backbones provide continuity while bases carry sequence meaning.
- Exam answers should match the command term and avoid adding unsupported extra claims.