Biology · Unity and diversity
A1.2 — Nucleic acids
Biology · SL / HL · syllabus-mapped notes
A1.2.1
DNA as the genetic material of all living organisms
State that DNA is the genetic material of all living organisms, and explain why RNA viruses are not an exception.
A1.2.2
Components of a nucleotide
Name the three components of a nucleotide, and draw one using the standard symbols.
A1.2.3
Sugar–phosphate bonding and the sugar–phosphate “backbone” of DNA and RNA
Explain how sugar–phosphate bonding creates a strong backbone that conserves the base sequence.
A1.2.4
Bases in each nucleic acid that form the basis of a code
Name the bases in DNA and in RNA, and state that their sequence is how information is coded.
A1.2.5
RNA as a polymer formed by condensation of nucleotide monomers
Explain how RNA is built from nucleotide monomers by condensation, and draw a nucleotide and an RNA polymer.
A1.2.6
DNA as a double helix made of two antiparallel strands of nucleotides with two strands linked by hydrogen bonding between complementary base pairs
Describe DNA as a double helix of two antiparallel strands held together by complementary base pairing, and draw it.
A1.2.7
Differences between DNA and RNA
Distinguish DNA from RNA by strand number, bases and sugar, and sketch ribose against deoxyribose.
A1.2.8
Role of complementary base pairing in allowing genetic information to be replicated and expressed
Explain how complementary base pairing allows genetic information to be replicated and expressed.
A1.2.9
Diversity of possible DNA base sequences and the limitless capacity of DNA for storing information
Explain why any sequence of any length is possible, and why that gives DNA an enormous storage capacity.
A1.2.10
Conservation of the genetic code across all life forms as evidence of universal common ancestry
Explain how a genetic code shared by all organisms is evidence of universal common ancestry.
A1.2.11
Directionality of RNA and DNA
Explain the 5' to 3' directionality of DNA and RNA, and why replication, transcription and translation all follow it.
A1.2.12
Purine-to-pyrimidine bonding as a component of DNA helix stability
Explain how pairing a purine with a pyrimidine keeps the helix a constant width, and therefore stable.
A1.2.13
Structure of a nucleosome
Describe the structure of a nucleosome, and use visualization software to examine one.
A1.2.14
Evidence from the Hershey–Chase experiment for DNA as the genetic material
Explain how the results of the Hershey–Chase experiment show that DNA, not protein, is the genetic material.
A1.2.15
Chargaff’s data on the relative amounts of pyrimidine and purine bases across diverse life forms
Explain how Chargaff's data falsified the tetranucleotide hypothesis.