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3.1 - Genes
Understandings
A gene is a heritable factor that consists of a length of DNA and influences
a specific characteristic
A gene occupies a specific position on a chromosome
The various specific forms of a gene are alleles
Alleles differ from each other by one or only a few bases
New alleles are formed by mutation
The genome is the whole of the genetic information of an organism
The entire base sequence of human genes was sequenced in the Human
Genome Project
Applications
The causes of sickle cell anaemia, including a base substitution mutation,
a change to the base sequence of mRNA trancribed from it and a change
to the sequence of a polypeptide in haemoglobin
Comparison of the number of genes in humans with other species
Skills
• Use of a database to determine differences in the base sequence of a gene
in two species
Genes and Loci
Substantive
What is DNA?
3.1 - Genes 1
, DNA is the genetic blueprint which codes for, and determines, the
characteristics of an organism
This includes the physical, behavioural and physiological features of
the organism
What are Chromosomes?
DNA is packaged and organised into discrete structures called
chromosomes
What is a Gene?
A gene is a sequence of DNA that encodes for a specific trait (traits
may also be influenced by multiple genes)
What is a Locus?
The position of a gene on a particular chromosome is called
the locus (plural = loci)
Diagram
3.1 - Genes 2
3.1 - Genes
Understandings
A gene is a heritable factor that consists of a length of DNA and influences
a specific characteristic
A gene occupies a specific position on a chromosome
The various specific forms of a gene are alleles
Alleles differ from each other by one or only a few bases
New alleles are formed by mutation
The genome is the whole of the genetic information of an organism
The entire base sequence of human genes was sequenced in the Human
Genome Project
Applications
The causes of sickle cell anaemia, including a base substitution mutation,
a change to the base sequence of mRNA trancribed from it and a change
to the sequence of a polypeptide in haemoglobin
Comparison of the number of genes in humans with other species
Skills
• Use of a database to determine differences in the base sequence of a gene
in two species
Genes and Loci
Substantive
What is DNA?
3.1 - Genes 1
, DNA is the genetic blueprint which codes for, and determines, the
characteristics of an organism
This includes the physical, behavioural and physiological features of
the organism
What are Chromosomes?
DNA is packaged and organised into discrete structures called
chromosomes
What is a Gene?
A gene is a sequence of DNA that encodes for a specific trait (traits
may also be influenced by multiple genes)
What is a Locus?
The position of a gene on a particular chromosome is called
the locus (plural = loci)
Diagram
3.1 - Genes 2
