AP Biology

1. AP Biology Test Return/Lab return/Study guide return Chapter 13-15 Next test December 6  Study guide Corrections too

2. Chapter 13- Meiosis • Heredity- or inheritance transmission of traits from one generation to the next • Genes- coded information with traits, segments of DNA • Gametes- reproductive cells (sperm and egg)

3. Somatic cells- cells other than reproductive cells • Locus- a specific location on a chromosome • Asexual reproduction vs Sexual reproduction • Life cycle- generation to generation sequence of stages in reproductive history

4. Chromosomes • 46 human chromosomes (somatic) 2n (2 sets) • Karyotype • Autosomes vs sex chromosomes • Haploid (n) – cells with a single chromosome set

5. Fertilization- union of gametes (sperm and egg) zygote is formed • Zygote- fertilized egg, diploid because it contains 2 haploid sets from each parent • Meiosis- process to form gametes, reducing chromosome number by half

7. Meiosis • Interphase • Meiosis I • Separates homologous chromosomes • Meiosis II • Separates sister chromatids

8. Meiosis I • Prophase I • Crossing over occurs • Metaphase I • Homologous chromosome PAIRS line up at middle • Anaphase I • Duplicated homologous chromosomes separate • Telophase I, Cytokinesis • 2 cells result

10. Meiosis II • Prophase II • Metaphase II • Homologous chromosomes (sister chromatids) line up at center • Anaphase II • Sister chromatids separate • Telophase II, Cytokinesis

12. Mendel and Gene Idea Chapter 14 • Blending hypothesis- genetic material mixes in a manner which blends traits • Mendel- peas • Traits- characteristic inherited • True-breeding – plants self-pollinate to have same traits as parents • Hybridize- cross (or cross-pollinate)

13. P generation – parent • F1 = Offspring of P • F2 = offspring of F1

14. Genotype – • Phenotype – • Alleles- alternative forms of traits • Dominant- • Recessive-

15. AP Biology

16. Mendel’s laws • Law of segregation- • 2 alleles for a heritable character separate during gamete production (end up in different gametes) • Law of independent assortment- • Each pair of alleles segregates independently during gamete formation.

17. Problem: • Homozygous black rabbit mates with a homozygous white rabbit Phenotypic ratio: Genotypic ratio:

18. Problem: • Carry out a cross for the F1 generation: Phenotypic ratio: Genotypic ratio:

19. Problem: • A brown tall rabbit is mated with a white short rabbit. Brown and tall are dominant. Construct a punnett square

20. Problem: • Use F1 to determine the F2 generation

21. Laws of probability govern Mendelian inheritance • Probability of tossing heads with normal coin: • Probability of rolling a 3 with a 6 sided die:

22. Law of multiplication • Used to determine probability of two or more independent events. • Probability that 2 girls are born in a row to a family: • Probability that 6 girls are born in a row to a family:

23. Law of addition: • The probability of an event that can occur in two or more mutually exclusive ways • The probability of producing an F2 heterozygote:

24. Mendel genetics = simple genetics • Incomplete dominance – intermediate offspring • Codominance– both traits are shown

25. Many genes exist in populations in more than two allelic forms: • ABO blood groups: • IA, IB, i

26. Pleiotrophic- when genes affect more than one phenotypic characteristic • Polygenic inheritance- additive effects of two or more genes on a single phenotypic character.

27. Pedigrees

28. AP BIO • Finish Chapter 15 • Lab Tuesday • Test Thursday

29. AP Biology • Thomas Morgan • Worked with Drosophila (fruit flies) • Discovered wild type – characteristic found in nature • Mutants were alternatives to the wild type Fruit flies- carry eye color on X chromosome White eyes – w Red eyes – w+

30. Not All organisms are XX and XY

31. SRY gene on Y • SRY (sex-determining region of Y) gene was discovered in 1990. • Individuals with the SRY gene embryonic gonads develop into testes • Individuals without the SRY gene develop ovaries

32. Genes located on Sex Chromosomes • Sex-linked genes • On Y = Y-linked genes • On X = X-linked genes • Color blindness • Hemophilia • Duchenne muscular dystrophy

33. Problem: • Mother heterozygous for color blindness • Father is not colorblind Results:

34. Barr body • Females inherit 2 X chromosomes, only 1 X chromosome is active. • Barr body- during development 1 X chromosome per cell condenses into a compact Barr body. • Barr bodies are not expressed.

35. Linked genes • Linked genes – genes located near each other on the same chromosome and tend to be inherited together.

36. Crossing over • Accounts for recombination of linked genes • Occurs in prophase I meiosis I • New combinations result in varied offspring

37. Alterations of chromosome number • Nondisjunction – • members of a pair of homologous chromosomes do not separate properly during meiosis I • Or sister chromatids fail to separate during meiosis II. • Trisomic, monosomic cells • Polyploid – organisms with more than two complete sets of chromosomes

38. Breakage of chromosome structure • Deletion – when a chromosomal fragment is lost • Duplication- occurs when a fragent becomes attached as an extra segment to a sister chromatid. • Inversion – When chromosome fragment reattaches to the original chromosome in the reverse direction • Translocation- fragment joins a non homologous chromosome