Essential Idea
Every living organism inherits a blueprint for life from its parents.
Understandings
A gene is a heritable factor that consists of a length of DNA and influences a specific characteristic.
Sequencing of the human genome shows that all humans share the vast majority of their base sequences but also that there are many single nucleotide polymorphisms that contribute to human diversity.
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 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 (VIDEO).
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.
Key Vocabulary
Heredity
Gene
Allele
Genome
Mutation
Base substitution
Sickle cell anemia
Hemoglobin
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 3.
Pages 119-134
Challenge Yourself (p.122)
Worked Example (p.123-124)
Exercises (p.134)
Notes
A detailed set of notes, prepared by Bob Smullen, examining all of the IB learning expectations.
A detailed set of notes, prepared by Stephen Taylor, examining U1 - U7 and A1.
A series of questions, prepared by Stephen Taylor, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, prepared by Jacob Cedarbaum, examining all of the IB learning expectations.
3.1 Study Questions (NEW Syllabus)
A series of questions, prepared by Jacob Cedarbaum, to help check your understanding of the IB learning expectations. This is VERY GOOD practice. Answers (OLD).
Learning Activities
Comparing Amino Acid Sequences
This activity will help see the similarities between different species. By examining the amino acid sequence of cytochrome C from different organisms, we can better understand the relationships between humans and other organisms.
Living Things Share Common Genes
This narrated animation, by DNA from the Beginning, outlines the similarities between a specific gene in humans and yeast cells. It also examines the process by which these similarities are determined and connects to the similarities between all living organisms.
This very short read (<5 minutes) and interactive animation, by National Geographic, illustrates the similarities between the human genome and other organisms.
This virtual lab, prepared by McGraw-Hill, will help you better understand how mutations can lead to altered protein structure.
Supplemental Reading
This video outlines the differences between genes and alleles while making connections to how they are expressed within living organisms.
This video outlines what SNPs are (single nucleotide polymorphisms) and how they affect living organisms.
This video outlines what genes are and how they are related to DNA and chromosomes. It is part of a great series covering many of the IB learning expectations.
This video outlines the origins of genes and the effects that mutations have on the effect of these genes.
This video outlines the structure and function of genes within living organisms.
Video Tutorials
Supplemental Videos
This video outlines what mutations are and how they're caused. It also examines the different types of mutations and how they might affect living organisms. It explores Sickle Cell Anemia as a real-world example.
This video is a little longer but does a fantastic job outlining the evolutionary origins of the sickle cell disease. Additionally, it describes the mutation involved in the sickle cell trait and the genetics involved in passing the trait from one generation to the next.
This video outlines what a genome is and how we successfully managed to sequence the entire human genome. It also examines how this information will be useful to society as we continue to improve our understanding of it.