Heredity Unit 1 Test Review

1. Another name for a sex cell. GAMETE

2. Identify the process that creates gametes. MEIOSIS

Distinguish between haploid (N) and diploid (2N) cells. 3. Sex cell. 4. Liver cell. 5. Skin cell. 6. Egg cell. N 2N N

Calculate the haploid (N) number of chromosomes given the diploid (2N) number, and vice versa. 7. Chromosome number of sex cells. 8. Chromosome number of all other cells. 9. If a diploid cell with 24 chromosomes undergoes meiosis, what will the chromosome number be AFTER the creation of sex cells?

10. Explain why gametes are haploid. Sex cells are haploid, having HALF the number of chromosomes, because the other half come will come from the opposite sex cell during fertilization

Describe the major events of meiosis. 11. How many genetically unalike sex cells are produced from meiosis? 4

12. This is created during prophase I of meiosis and consists of a homologous pair of chromosomes joined together. TETRAD

13. Name this chart. 14. How many pairs of chromosomes are usually in a human? KARYOTYPE 23

15. Name the two sex chromosomes in a human female. XX

16. Name the two sex chromosomes in a human male. XY

Identify the sex chromosomes on a karyotype to determine the gender of an individual. 17. Boy or Girl? BOY

18. Name these type of mutations during meiosis. NONDISJUNCTION

Diagnose any nondisjunction errors in a given karyotype. 19. What’s wrong with this karyotype? TRISOMY 21

20. The different forms of a gene. Each sex cell has one of these for every gene. ALLELE

Describe the behavior of alleles in gametes during the production of a zygote. 21. When parents produce offspring, the offspring receives how many alleles from each parent for each trait? ONE

Explain Mendel’s Law of Independent Assortment. 22. List all of the allele combinations that the following parent will produce in its sex cells: AABb There are two: AB and Ab

23. What process is shown below?

Observe and practice how Punnett squares are used to predict the possible genotypes of offspring. a A aa 24. Genotype Frequency: Aa 2/4 aa 2/4

Contrast nature and probability in producing genetic offspring. 25. What is the chance of flipping tails when you flip a coin? 26. What is the chance of a heterozygous parent donating a recessive allele to its offspring? 50%

Identify both the genotype and phenotype of an individual. 27. Physical Characteristic 28. Tall Pea Plant 29. Rr 30. Rough and yellow PHENOTYPE GENOTYPE

Distinguish between homozygous and heterozygous individuals. 31. Having two identical alleles for a trait. 32. Aa 33. Having two different alleles for a trait. 34. BB 35. rr HOMOZYGOUS HETEROZYGOUS

Recognize that genes on separate chromosomes follow the Law of Independent Assortment, while genes on the same chromosome are “linked” and follow different inheritance patterns than unlinked genes 36. On the diagram below, which genes would give a 9:3:3:1 ratio in a dihybrid cross? A and B, or A and C? 37. Why are A and B “linked” traits? A and C They are on the same chromosome

38. Explain why fruit flies are useful in studying the principle of genetics. They have short generation times, reproduce quickly, and have LOTS of offspring

39. When two alleles for a trait are equal in dominance. CODOMINANCE

Complete a Punnett Square for genes that show codominance. B B WW BB= black WW= white 40. Phenotype Frequency: BLACK AND WHITE 4/4

Complete a Punnett Square for genes that show codominance. IAIA IAIA IBIB i AB: 2/4 A: 2/4 41. What are the phenotypes and ratios?

42. When a dominant allele does not completely dominate over a recessive allele. Example: Snapdragons INCOMPLETE DOMINANCE

Complete a Punnett Square for genes that show incomplete dominance. R R WW RR= red WW= white 43. Phenotype Frequency: PINK 4/4

Define a “sex-linked gene.” 44. Why do males have sex-linked traits more often than females? The genes for sex-linked traits are recessive and carried on the X chromosome. Males only have one X chromosome, so they are more likely to have the recessive trait show.

Trace a gene in a pedigree chart as it passed down from generation to generation. 45. Using the letter “A,” what is the genotype of person 7? XaYXaY