1. Genetics – the study of heredity

2. At the end of this topic you should be able to 1. Discuss the variation and diversity of organisms 2. Define the term species 3. Define the term heredity 4. Give an example of heredity 5. Define the term gene expression 6. Example of a gene expression 7. Definition of a gene 8. Outline the role of a gene 9. Know the structure of a chromosome – refer to DNA and protein structure

3.  Variation 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 human

4. A group of organisms capable of interbreeding and producing fertile offspring. Humans Cats Dogs Oak Trees Ash Trees

5. http://commons.wikimedia.org/wiki/File%3APanthera _tigris_tigris.jpg

6. http://commons.wikimedia.org/wiki/File%3ALio n_in_masai_mara.jpg

7. http://commons.wikimedia.org/wiki/File%3ALiger _couple.jpg

8. http://files.redux.com/images/f2f1c0d86ce7601a4ce421f71d994f40/raw

9. Males are sterile but female are fertile – so not a new species http://www.lifeinthefastlane.ca/wp-content/uploads/2007/10/tigons_sfw.jpg

11.  What is meant by variation?  Give the definition for species  Why is a liger not a new species?

12. Heredity is the passing on of features from parents to offspring by means of genes Also called Genetic Inheritance

13.  A gene is a length of DNA that codes for a specific protein  It is the unit of inheritance  It is found on a chromosome  It contains instructions to make a particular protein  It directly influences the characteristics of an organism

14.  Characteristics 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.

15. Not all genes are expressed Genes produce characteristics or traits that are inherited Eg: Gene for Tallness Organism is small – Why? Maybe due to poor nutrition

16. Characteristics = heredity + environment

17. 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.

18. Chromosomes contain a number of genes

19. Chromosomes are made up of 60% protein 40% DNA Genes are arranged along the DNA of the chromosome

20. Large sections of the chromosome do not contain genes This DNA is called Non Coding DNA It’s function is not yet clear

22.  Thread like structures  Contain DNA  Contain Protein  Contain Genetic Information  Occur in pairs  Found in the nucleus of all cells

23. Can you ……………. 1. Define the term heredity 2. Define the term gene 3. Outline the role of a gene 4. Define the term gene expression 5. Know the structure of a chromosome