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AP Biology Exam Review 2003-2004 Heredity and Evolution – 25%

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Presentation on theme: "AP Biology Exam Review 2003-2004 Heredity and Evolution – 25%"— Presentation transcript:

1 AP Biology Exam Review Heredity and Evolution – 25%

2 Heredity and Evolution Heredity – 8% Molecular Genetics – 9% Evolutionary Biology – 8%

3 Heredity Meiosis and gametogenesis Eukaryotic chromosomes Inheritance patterns

4 Asexual vs. Sexual Reproduction Asexual reproduction: binary fission, regeneration, vegetative propagation, budding Sexual reproduction: result of gametic fusion, gametes formed from meiosis, promotes genetic recombination (variety) Meiosis: process of gametic nuclear transfer

5 Sexual life cycles Remember: Asexual life cycles do not require the fusion (fertilization) of sperm and egg.

6 Meiosis overview Each normal 2N (diploid) cell has 2 sets of chromosomes, one from each gamete. Gametogenesis: specialized cells (spermatocyte, oocyte) undergoing meiosis to produce gametes with some combination of the 2 chromosome sets

7 Important vocabulary Homologous chromosomes: pair of like chromosomes, having similar length, centromere position, gene loci Linkage group: genes that are linked on the same chromosome (linked loci) Locus (pl. loci): site on chromosome where gene is located on the chromosome

8 Meiosis


10 Crossing over Genetic variation in meiosis result of crossing over when chromosomes aligned in tetrad formation Breaks linkage groups (genes found on the same chromosome)

11 Oogenesis

12 Spermatogenesis

13 Pine life cycle

14 Eukaryotic chromosome Allele: alternative form of the same genes Chromosome: condensed double helix (DNA)

15 Eukaryotic DNA packing Nucleosomes: beads on a string (beads = histones) Chromatin: condensed nucleosomes Looped chromatin on protein scaffolding Chromosomes

16 Mendels work Law of independent assortment Law of segregation Dominant vs. recessive phenotype Used peas because of fast generations, easily recognizable characteristics, two alleles

17 Inheritance patterns Mendelian inheritance: AA & Aa = dominant phenotype; aa = recessive phenotype Codominance: Aa = shows both A and a equally

18 Incomplete dominance Intermediate inheritance AA = dominant Aa = half way between AA and aa aa = recessive phenotype

19 Inheritance patterns Hybrid: mixed genes between two species Pleiotropy: ability of one gene to affect many different genes

20 Epistasis Expression of one gene determines the expression of another gene

21 Polygenic inheritance Many genes affecting a phenotype Leading to many possible phenotypes of a trait

22 Multiple alleles

23 Test cross If Mendelian inheritance, AA and Aa genotypes are indistinguishable. Crossing dominant phenotype with aa. 100% dominant = PP; 1:1 = Pp

24 Sex-linked Sex-linked: gene loci on sex chromosome (X or Y) Ex: hemophilia, color blindness First discovered in 1910 by Thomas Hunt Morgan Autosomal: gene loci on non-sex chromosome

25 Sex linkage Look for inheritance patterns that deviate from 3:1 or 1:1. Also look for disorders affecting mostly males.

26 Recombination frequencies

27 X-inactivation & Barr bodies

28 Nondisjunction

29 Nondisjunction disorders

30 Human pedigrees Square = male Circle = female Colored in = affected

31 Molecular Genetics – 9% RNA and DNA structure and function Gene regulation Mutation Viral structure and replication Nucleic acid technology and application

32 DNA structure Nucleotide: nitrogen base, deoxyribose sugar, phosphate group Nitrogen bases: adenine, thymine, cytosine, guanine Joined 5 – 3 (phosphodiester bonds) Sugar-phosphate backbone

33 RNA structure Nucleotide: nitrogen base, ribose, phosphate group Nitrogen bases: uracil, adenine, guanine, cytosine Single stranded Joined 5-3 In eukaryotes: RNA produced in nucleolus of nucleus. tRNA, rRNA, mRNA

34 Griffith experiment Avery did a follow-up experiment and coined transformation.

35 Phage

36 Hershey and Chase

37 DNA replication models

38 Meselson and Stahl

39 Origin of replication

40 DNA elongation

41 DNA synthesis Leading strand: made continuously Lagging strand: Okazaki fragments

42 DNA priming Necessary for starting DNA synthesis

43 Okazaki fragments

44 Telomeres Necessary to preserve DNA through successive rounds of DNA replication

45 Controlling gene expression Gene expression = transcription RNA transcript is translated into amino acid polymer. Operons are examples of prokaryotic gene expression control. Methylation is an example of eukaryotic gene expression control.

46 One enzyme, one protein (controlling gene expression) Beadle and Tatum

47 Overview Transcription: DNA RNA Translation: RNA amino acid polymer (peptide)

48 Transcription Initiation Elongation Termination


50 RNA processing Removing introns that interrupt the express-able code (exons) Also adding poly-A tail and 5-CAP

51 tRNA tRNA charged with amino acid assists ribosomes with protein synthesis

52 Translation - initiation

53 Translation - elongation

54 Translation - termination

55 Point mutation Codon can be mutate due to substitution.

56 Insertion & deletion Frameshift mutation Mutation: spontaneously occurs; basis of variation in populations

57 Viral reproduction Lytic vs. lysogenic life cycle Viruses are not cells. Viruses are particles of nucleic material and protein that requires host cells for reproduction. Bacteriophage: viruses that infect bacteria

58 Lytic life cycle

59 Lysogenic life cycle

60 HIV Retrovirus RNA nucleic acid Requires reverse transcriptase enzyme (RNA DNA)

61 Bacterial replication

62 Using recombinant bacteria

63 Transduction

64 Plasmid biotechnology

65 Recombinant DNA Restriction enzymes cut host DNA and gene of interest Sticky ends complementary (match), enabling recombination

66 Genomic library Having multiple copies of DNA or phage

67 PCR Polymerase chain reaction: heat, cool, add primer Forms cDNA (clonal DNA) library

68 Gel electrophoresis

69 RFLP: cut sites in junk DNA Restriction fragment length polymorphism

70 Southern blotting

71 Sanger Method to deduce the DNA sequence that is unknown

72 Gene therapy

73 Phage as a vector Transduction: using virus as a means to transport eukaryotic gene into bacteria

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