Topic 3.1

Essential idea: Every living organism inherits a blueprint for life from its parents.


Definition gene and allele

3.1.U4 Alleles differ from each other by one or only a few bases

allelic difference

3.1.U5 New alleles are formed by mutation

What is a gene mutation?

A gene mutation involves a change in the nucleotide sequence of DNA and is the ultimate source of genetic diversity.

3.1.U6 The genome is the whole of the genetic information of an organism

Definition of genome

3.1.U7 The entire base sequence of human genes was sequenced in the Human Genome Project

Definition of genome


3.1.A1 The causes of sickle cell anemia, including a base substitution mutation, a change to the base sequence of mRNA                      transcribed from it and a change to the sequence of a polypeptide in hemoglobin

What is the consequence of a base substitution mutation using the example of sickle-cell anemia?

Place mouse pointer on figure to view base mutation changes to the protein structure of hemoglobin in sickle-cell anemia.

Base mutation and sickle-cell anemia

Use the figure to explain how the base mutation cause sickle-cell anemia.

Click on "Show explanation sickle-cell anemia" below to check your explanation.

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Sickle-cell anemia explained

3.1.A2 Comparison of the number of genes in humans with other species

Use the figure to compare the genes of humans to other organisms.

Place mouse pointer on the figure to comparison of genes between humans and other organisms.

Base mutation and sickle-cell anemia

3.1.S1 Use a database to determine differences in the base sequence of a gene in two species

Go to Bioinformatics Basics
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