Notes Compiled by Giorgia Lobban (2021)
DNA- Code of Life
Life at Molecular, Cellular and Tissue Level
SAGS List
Candidates should know
DNA structure and coding
How the work done by many scientists allowed Watson and Crick to unravel the genetic code
(1953) and, in the 1960s, the mechanism of protein synthesis and DNA replication.
The structure and location of DNA and RNA (mRNA, tRNA only) in a cell.
The simple structure of nucleotides, including the names of the four nitrogenous bases of
DNA (adenine [A], thymine [T], cytosine [C] and guanine [G]) and that uracil replaces thymine
in RNA, and which bases are complementary.
That mitochondrial DNA also exists and remains unaltered from mother to child. That this is
used to determined relatedness.
Protein synthesis
The process of transcription of mRNA from DNA and where it takes place in a cell. Refer to
role of polymerase.
The translation of mRNA (including the role of tRNA and amino acids) into specific proteins
and where this takes place in a cell. Reference to other types of RNA is not required. The
terms 'codon' and 'anticodon' should be familiar.
How aberrations occur: the definition and effect of point and frameshift mutations: Refer
only to insertion, deletion, and substitution mutations. Mutations can be caused by
mutagens and chance.
Application of DNA technology
That highly variable, non-coding DNA is used for 'fingerprinting' and the significance of
'fingerprinting'. The role of PCR (Polymerase Chain Reaction) in making this possible from
small DNA samples. Interpretation and importance of a DNA 'fingerprint' is required but not
detail of the process.
1|Page
, Notes Compiled by Giorgia Lobban (2021)
DEFINITIONS
Gene: a short segment of DNA that codes for a particular protein
Nucleotide: monomers of DNA
DNA Replication: transmitting identical DNA to each new cell
Base Triplets: three consecutive nitrogenous bases on the DNA strand
Protein: a polymer with amino acids as monomers
Protein Synthesis: process whereby proteins are manufactured in living cells
Codon: three nitrogenous bases that code for a particular amino acid
Anticodon: three exposed nitrogenous bases on tRNA molecule
Stop Codons: three codons that do not code for amino acids
Antibiotic: a medicine that inhibits the growth of or destroys microorganisms
Auto-Immune Disease: a disease whereby the body attacks its own cell
Mutation: a sudden, unexpected change in the genetic makeup of an organism
DNA Profiling: a scientific method of analysing samples of DNA to create a
unique profile for an individual
Gel Electrophoresis: method using an electrical charge to separate large DNA
molecules
DNA STRUCTURE AND CODING
NUCLEIC ACIDS
Control the synthesis of proteins and therefor structure and functioning of all living organisms
Two types:
- DNA (Deoxyribonucleic Acid)
- RNA (Ribonucleic Acid)
DNA
Discovered by Maurice Wilkins and Rosalind Franklin
Francis Crick and James Watson built a model (1953):
- Twisted ladder
- Runners made of sugar and phosphates
- Rungs or organic bases
2|Page
DNA- Code of Life
Life at Molecular, Cellular and Tissue Level
SAGS List
Candidates should know
DNA structure and coding
How the work done by many scientists allowed Watson and Crick to unravel the genetic code
(1953) and, in the 1960s, the mechanism of protein synthesis and DNA replication.
The structure and location of DNA and RNA (mRNA, tRNA only) in a cell.
The simple structure of nucleotides, including the names of the four nitrogenous bases of
DNA (adenine [A], thymine [T], cytosine [C] and guanine [G]) and that uracil replaces thymine
in RNA, and which bases are complementary.
That mitochondrial DNA also exists and remains unaltered from mother to child. That this is
used to determined relatedness.
Protein synthesis
The process of transcription of mRNA from DNA and where it takes place in a cell. Refer to
role of polymerase.
The translation of mRNA (including the role of tRNA and amino acids) into specific proteins
and where this takes place in a cell. Reference to other types of RNA is not required. The
terms 'codon' and 'anticodon' should be familiar.
How aberrations occur: the definition and effect of point and frameshift mutations: Refer
only to insertion, deletion, and substitution mutations. Mutations can be caused by
mutagens and chance.
Application of DNA technology
That highly variable, non-coding DNA is used for 'fingerprinting' and the significance of
'fingerprinting'. The role of PCR (Polymerase Chain Reaction) in making this possible from
small DNA samples. Interpretation and importance of a DNA 'fingerprint' is required but not
detail of the process.
1|Page
, Notes Compiled by Giorgia Lobban (2021)
DEFINITIONS
Gene: a short segment of DNA that codes for a particular protein
Nucleotide: monomers of DNA
DNA Replication: transmitting identical DNA to each new cell
Base Triplets: three consecutive nitrogenous bases on the DNA strand
Protein: a polymer with amino acids as monomers
Protein Synthesis: process whereby proteins are manufactured in living cells
Codon: three nitrogenous bases that code for a particular amino acid
Anticodon: three exposed nitrogenous bases on tRNA molecule
Stop Codons: three codons that do not code for amino acids
Antibiotic: a medicine that inhibits the growth of or destroys microorganisms
Auto-Immune Disease: a disease whereby the body attacks its own cell
Mutation: a sudden, unexpected change in the genetic makeup of an organism
DNA Profiling: a scientific method of analysing samples of DNA to create a
unique profile for an individual
Gel Electrophoresis: method using an electrical charge to separate large DNA
molecules
DNA STRUCTURE AND CODING
NUCLEIC ACIDS
Control the synthesis of proteins and therefor structure and functioning of all living organisms
Two types:
- DNA (Deoxyribonucleic Acid)
- RNA (Ribonucleic Acid)
DNA
Discovered by Maurice Wilkins and Rosalind Franklin
Francis Crick and James Watson built a model (1953):
- Twisted ladder
- Runners made of sugar and phosphates
- Rungs or organic bases
2|Page
