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 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 and Skills:-A: The causes of sickle cell anemia, including a base substitution mutation, a change to the base sequence of mRNA transcribed from it, and the change to the sequence of a polypeptide in hemoglobin.-A: Comparison of the number of genes in humans with other species.-S: Use a database to determine differences in the base sequence of two species.

Guidance:-Students should be able to recall one specific base substitution that causes glutamic acid to be substituted by valine as the 6th amino acid in the haemoglobin polypeptide.-The number of genes in a species should not be referred to as a genome size as this term is used for the total amount of DNA. At least one plant and one bacterium should be included in the comparison, and at least once species with more genes and one with fewer genes than a human.-The GenBank data base can be used to search for DNA base sequences. The cytochrome c gene sequence is available for many different organisms and is of particular interest because of its use in reclassifying organisms into three domains.-Deletions, insertions, and frame shift mutations do not need to be included.

What is a gene?

A gene is a segment of DNA, located on the chromosomes, that carries hereditary instructions from parent to offspring.A gene codes for a protein that gives a characteristic.

What is an allele?

An allele is one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene.

What is a mutation?

A gene mutation is a permanent change in the DNA sequence that

makes up a gene .

may produce a different amino acid sequence in the protein

translated.

may not change the protein because of the degenerate

nature of the genetic code.

expression of the mutated gene may or may not be

beneficial to the organism.

Substances that cause mutation are called mutagens and include

chemicals and radiation. 

Cystic Fibrosis - Caused by a mutation of the cystic fibrosis

transmembrane conductance regulator (CTFR) gene

- Autosomal recessive

- Presence of thick, sticky mucus in digestive organs and airways

http://discovermagazine.com/~/media/Images/Issues/2013/September/a-look-inside-cystic-fibrosis.jpg

Sickle-cell anemia mutation

Effect on the phenotype

animation

Glutamic acid is substituted by valine.

http://www.glossary.periodni.com/images/glutamic_acid.jpghttp://images.tutorvista.com/cms/images/38/valine.PNG

Characteristics of Sickle Cell

- Weakness, fatigue, shortness of breath.-Curved shaped blood cells that cannot carry oxygen efficiently.-Hemoglobin can crystalize, causing blood flow to be slow or blocked.- Resistance to malaria

Those with one bad copy of the gene are at the highest advantage in areas where malaria is common.

Define genome

Genome is the whole of the genetic information of an organism.

How to sequence DNA

https://o.quizlet.com/5jzEdgB-Rd7KvAiJMNbRFQ_m.jpg

DNA Segment

dNTP’s ddNTP’s

Adapted from http://www.gida.de/testcenter/biologie/bio-dvd040/jpg/14_Ablauf.jpg

Adapted from http://www.gida.de/testcenter/biologie/bio-dvd040/jpg/14_Ablauf.jpg

DNA Sequence

Complimentary Sequence

https://o.quizlet.com/5jzEdgB-Rd7KvAiJMNbRFQ_m.jpg

The Human Genome Project- An international project aimed at sequencing the complete human genome.- Completed in 2003- Available online

What did it teach us?-We are all different and the same.-Differences between us are the result of minor differences in our coding.

HomeworkHomeworkVocab Other

• Gene• Heritable• Characteristic• Locus/loci• Alleles• Mutation• Gene therapy• Sickle cell anemia• Sickle cell trait• The Human Genome Project• Cytochrome C

• Challenge yourself 2• Exercises 1-3• TOK pg 121 HL/ 128

SL• TOK 124 HL/ 131 SL