Heredity and Gene Expression
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Transcript of Heredity and Gene Expression
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Heredity and Gene ExpressionGenetics the study of heredityLesson ObjectivesAt the end of this topic you should be able to Discuss the variation and diversity of organismsDefine the term speciesDefine the term heredityGive an example of heredityDefine the term gene expressionExample of a gene expressionDefinition of a geneOutline the role of a geneKnow the structure of a chromosome refer to DNA and protein structure
VariationVariation means that there are differences between members of the same species i.e. a population
Think of all the variations within your class even though you are all humanSpeciesA group of organisms capable of interbreeding and producing fertile offspring.
HumansCatsDogsOak TreesAsh Trees
Tiger a member of the cat family
http://commons.wikimedia.org/wiki/File%3APanthera_tigris_tigris.jpgLion a member of the cat family
http://commons.wikimedia.org/wiki/File%3ALion_in_masai_mara.jpgLiger = Male Tiger + Female Lion
http://commons.wikimedia.org/wiki/File%3ALiger_couple.jpgLiger Family in Chinese Zoo
http://files.redux.com/images/f2f1c0d86ce7601a4ce421f71d994f40/rawTigon = Male tiger + Female Lion
Males are sterile but female are fertile so not a new specieshttp://www.lifeinthefastlane.ca/wp-content/uploads/2007/10/tigons_sfw.jpgFor a new species to be formed all the offspring must be fertileLearning CheckWhat is meant by variation?
Give the definition for species
Why is a liger not a new species?HeredityHeredity is the passing on of features from parents to offspring by means of genes
Also calledGenetic InheritanceGenesA gene is a length of DNA that codes for a specific proteinIt is the unit of inheritanceIt is found on a chromosomeIt contains instructions to make a particular proteinIt directly influences the characteristics of an organismCharacteristics are controlled by genes.
For example everyone has genes which determine hair colour.
But not everyone has the same version of those genes.
So there is more than one type of gene for hair colour that you could have.GenesGene ExpressionNot all genes are expressed
Genes produce characteristics or traits that are inherited
Eg: Gene for TallnessOrganism is small Why?Maybe due to poor nutrition
CharacteristicsCharacteristics = heredity + environment
Heredity is the passing on of _________ from parents to ______________ by means of ______. A gene is the unit __________________. They are found on a _________________. They contain ________________ to make a particular _______________. Gene expression is the way in which _____ ________ in a gene is decoded.
Learning CheckChromosomes
Chromosomes contain a number of genesChromosome StructureChromosomes are made up of
60% protein40% DNA
Genes are arranged along the DNA of the chromosomeNon Coding DNALarge sections of the chromosome do not contain genes
This DNA is called Non Coding DNA
Its function is not yet clear
Chromosome structure
ChromosomesThread like structuresContain DNAContain ProteinContain Genetic Information Occur in pairs Found in the nucleus of all cells
What have you learned?Can you .Define the term heredityDefine the term gene Outline the role of a geneDefine the term gene expressionKnow the structure of a chromosome
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