1. Genetics & Heredity

2. Who was Gregor Mendel?

3. Austrian monk who studied mathematics and science As a boy he experimented with pea plants Made careful use of scientific methods, which resulted in the first recorded study of how traits pass from one generation to the next.

4. What is GENETICS?

5. The study of how traits are inherited through the interactions of genes.

6. The nucleus of a cell contains genetic material –DNA Chromosomes –Genes www.kent.edu/projects/cell/page7.htm Genetic Material

8. Genes Genes are short sections of chromosomes Genes come in pairs and offspring inherit one copy of each gene from each parent http://www.accessexcellence.org

9. Genes come in pairs Since chromosomes come in pairs (one from mom, one from dad) Genes come in pairs http://anthro.palomar.edu/biobasis/ima ges/karyotype_male.gif

10. Define the following terms: Heredity Allele Trait

11. Define HEREDITY The passing of traits from parent to offspring

12. Allele Alleles are different versions of a gene Every gene has two or more alternatives http://library.thinkquest.org

13. Define TRAIT Characteristic or a way of looking, thinking, or being Traits that are genetic are passed down through the genes from parents to offspring

14. Describe RECESSIVE

15. A trait that is covered over, or dominated, by another form of that trait and seems to disappear Shown with a lower-case letter Example: c, d

16. What is HOMOZYGOUS?

17. Both alleles [forms of the gene] are the same When offspring inherit two dominant genes, (one dominant gene from each parent) they are said to be homozygous dominant (BB) When offspring inherit two recessive genes, (one recessive gene from each parent) they are said to be homozygous recessive (bb)

18. What is HETEROZYGOUS?

19. When alleles occur in different forms When offspring inherit one dominant gene and one recessive gene, they are said to be heterozygous (Bb) Since the dominant gene will be expressed, they are said to be heterozygous dominant

20. Describe DOMINANT

21. A trait that covers over, or dominates, another form of that trait Trait that always shows up, even when only one of the two alleles is in the dominant form Shown by a capital letter

22. Define GENOTYPE

23. An organism's genetic makeup Or the letters Example: Bb, bb, BB

24. Define PHENOTYPE

25. Outward physical appearance and behavior of an organism Example: black hair

26. What is a PUNNETT SQUARE?

27. A tool to predict the probability of certain traits in offspring that shows the different ways alleles can combine A way to show phenotype & genotype A chart that shows all the possible combinations of alleles that can result when genes are crossed

28. What is a PUNNETT SQUARE? Letters stand for dominant and recessive alleles An uppercase letter stands for a dominant allele Lowercase letters stand for recessive alleles

29. Read More About Punnett Squares Here: http://www.borg.com/~lubehawk/p square.htm

30. List the 3 Principles of Heredity

31. Traits are controlled by alleles on chromosomes An allele’s effect is dominant or recessive When a pair of chromosomes separate during meiosis the different alleles for a trait move into separate sex cells

32. What is meant by MULTIPLE ALLELES?

33. A trait that is controlled by more than two alleles is said to be controlled by multiple alleles Traits controlled by multiple alleles produce more than three phenotypes of that trait

34. What is meant by MULTIPLE ALLELES? For Example: The alleles for blood types in humans are called A, B, and O The O allele is recessive to both the A and B alleles

35. What is meant by MULTIPLE ALLELES? When a person inherits one A allele and one B allele for blood type, both alleles are expressed The person has the blood phenotype AB

36. What is meant by MULTIPLE ALLELES? A person with phenotype A blood inherited an A and an O allele (AO) ~OR~ an A and an A allele (AA)

37. What is meant by MULTIPLE ALLELES? Someone with phenotype B blood has the genotype BB or BO This person inherited either a B and an O allele ~OR~ Two B alleles

38. What is meant by MULTIPLE ALLELES? A person with phenotype O blood has the genotype OO

39. What is POLYGENIC INHERITANCE?

40. Occurs when a group of gene pairs acts together to produce a trait The effects of many alleles produces a wide variety of phenotypes