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Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
Genetics
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Genetics

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  1. DNA and Cellular Reproduction I. DNA (Deoxyribo-nucleic acid) A. Characteristics and general information- Watson and Crick 1- DNA is the genetic information molecule of life 2- DNA is the common molecular thread which connects all living things together 3- DNA ultimately controls the manufacture of all proteins 4- DNA is an effective information storage molecule 5- DNA consists of a double helix 6- DNA is self replicating B. Chemical makeup (basic building blocks: nucleotides) 1- Five carbon sugar ---> deoxyribose 2- Phosphate group 3- Nitrogen base (four different bases) C. Functions of DNA 1- Information storage 2- Information transmission 3- Control of protein synthesis (serves as master blueprint for manufacturing all proteins) 4- Self-replication II. RNA (Ribonucleic acid) A. Characteristics and general information 1- RNA is directly involved in protein synthesis 2- All RNA is transcribed from DNA 3- RNA is a molecule consisting of a single helix B. Chemical makeup (basic building blocks: nucleotides) 1- Five carbon sugar (different from DNA)---> ribose 2- Phosphate group 3- Nitrogen base (four different possibilities; one is different from DNA) C. Types and function of RNA 1- Messenger RNA (mRNA) is the working blueprint for properly arranging amino acids during protein synthesis, each specific protein is made from a different mRNA 2- Transfer RNA (tRNA) transports amino acids to site of protein synthesis and then “reads” the mRNA blueprint in order to properly position each amino acid in the protein molecule 3- Ribosomal RNA (rRNA) is the structural part of the ribosome, assists in the lining up of tRNA and mRNA
  2. III. Comparing DNA and RNA A. DNA 1- Sugar= deoxyribose 2- Nitrogen bases a. Adenine b. Guanine c. Cytosine d. Thymine 3- Double stranded molecule B. RNA 1- Sugar= ribose 2- Nitrogen bases a. Adenine b. Guanine c. Cytosine d. Uracil IV. Basic information about chromosomes A. Homologous or paired chromosomes B. Chromatids C. Alleles 1- homozygous alleles 2- heterozygous allele Cell Division: Mitosis and Cytokinesis I. Mechanics of cell division A. Initiation of cell division B. DNA replication C. Division of the DNA (mitosis) and cytoplasm (cytokinesis) II. Basic cell division sequence A. Interphase 1- DNA replication 2- transcription and translation (cell growth) B. Prophase C. Metaphase D. Anaphase (attachment to centromere) E. Telophase F. Cytokinesis III. Significance of mitosis (1 diploid to 2 diploid cells) A. Growth B. Maintenance (repair and replacement)--> intestinal lining/RBC’s) C. Asexual reproduction Vocabulary: centromere: chromosome: cytokinesis: diploid:
  3. haploid: interphase: metaphase: mitosis: prophase: telophase: Study Questions: 1. What are the specific functions of mitosis? 2. List and discuss the two major processes associated with interphase. 3. Describe how cytokinesis differs in plant and animal cells. 4. Make a chart listing the major activities and events associated with each of the mitotic phases. Meiosis: Producing Sex Cells I. Mechanics of meiosis A. Initiation of meiosis B. DNA replication C. Division of the DNA (meiosis) and cytoplasm (cytokinesis) D. Two gametes brought together to form a zygote II. Basic meiotic sequence (first and second meiotic sequences) A. Interphase 1- DNA replication 2- transcription and translation B. Prophase I C. Metaphase I D. Anaphase I E. Telophase I F. Prophase II G. Metaphase II H. Anaphase II I. Telophase II J. Cytokinesis III. Important events associated with meiosis A. Reduction of chromosome number by half (1 diploid to 4 haploid cells) B. Formation of sex cells (gametes) C. Genetic recombination through crossing over D. Differences between plant and animal cells 1. centrioles in animal cells 2. use of cell wall in plant cells IV. Comparison of mitosis and meiosis A. Mitosis 1- 1 cell ---> 2 cells 2- No change in chromosome number (total DNA content remains the same--diploid)
  4. 3- No consistent mechanism for introducing genetic variation B. Meiosis 1- 1 cell ---> 4 cells 2- Chromosome number reduced by half (total DNA content reduced by half--haploid) 3- Significant genetic variation introduced through crossing over Vocabulary: centriole centromere: crossing over: gamete: meiosis: zygote: Study Questions: 1. What happens as homologous chromosomes pair up during prophase I of meiosis? 2. How does metaphase of mitosis differ from metaphase I of meiosis? 3. What is the sole purpose of meiosis? 4. What specific activities, involving DNA, occur during interphase prior to both mitosis and meiosis? 5. Compare mitosis and meiosis on the following points: a. number of daughter cells produced. b. the amount of DNA in the daughter cells in contrast to the original cell. c. mechanism for introducing genetic variation. 6. What is a zygote and how is it formed? 7. Draw a nucleotide and then draw a 10 nucleotide linear sequence of DNA. Genetics & Inheritance Inheritance : Mendelian genetics I. The nature and relevance of Mendel’s studies on garden peas A. Characteristics studied by Mendel (7 traits) B. Why garden peas? 1- Many true breeding varieties available 2- The flower is self-fertile 3- Generation time is very short C. Difficulties overcome by Mendel 1- No concept of DNA or chromosomes 2- No concept of meiosis D. Some wise (educated guesses) decisions made by Mendel 1- Selection of well-defined, contrasting traits 2- Extensive groundwork completed prior to establishment of final experimental design 3- Extensive replication of crosses E. Understanding phenotype and genotype II. Results of Mendel’s work
  5. A. The principle of unit characters (elementum or genes) B. The phenomenon of dominant and recessive genes: a dominant allele masks the expression of its recessive allele 1- Cross: homozygous recessive dwarf (tt) and homozygous dominant tall (TT) plants 2- Result: all tall (Tt) offspring C. The principle of segregation: alleles separate from one another during the process of gamete (sex cell) formation 1- Cross: homozygous dwarf (tt) and homozygous tall (TT) individuals 2- Follow up cross between members of the F1 generation: heterozygous tall (Tt) and heterozygous tall (Tt) individuals 3- End result: Tall (TT and Tt) individuals and dwarf (tt) individuals [from above cross] D. The principle of independent assortment: alleles on different homologous chromosomes separate independent of one another III. Punnett squares IV. A look at segregation and independent assortment in light of meiosis A. Segregation B. Independent assortment Vocabulary: dominant gene: F1 generation: F2 generation: gene: genetic trait: genotype: hybrid: monohybrid cross: phenotype: principle of independent assortment: principle of segregation: Punnett square: recessive gene: Study Questions: 1. List and explain the four principles of genetics established by Mendel. 2. Complete a monohybrid cross between a pure breeding tall plant (TT) and a pure breeding dwarf plant (tt). Carry the cross through to the second generation (F2 generation) by letting the plants of the first cross (Tt) self-fertilize. Describe the phenotypes and genotypes of both generations. 3. Show how your knowledge of meiosis provides tangible evidence concerning Mendel’s Principles of Segregation and Independent Assortment. 4. Complete a monohybrid cross between (Tt X tt). List all the potential types of gametes produced by each parent and then combine them into all possible
  6. combinations in the offspring. List the various phenotypes and ratios from this cross. 5. List and discuss several of the approaches which made Mendel’s work successful. Monohybrid cross with heterozygous parents Tt X Tt T t (dad) T TT Tt (mom) t Tt tt 3:1 phenotypic ratio Dihybrid cross with homozygous parents TTRR X ttrr F1 generation: TtRr T=tall, t=short, R=red and r=white TtRr X TtRr (Dihybrid cross with heterozygous parent) TR Tr tR tr TR TTRR TTRr TtRR TtRr Tr TTRr TTrr TtRr Ttrr tR TtRR TtRr ttRR ttRr tr TtRr Ttrr ttRr ttrr Inheritance: Non- Mendelian Genetics and environmental influences I. Mutations -- a heritable change in DNA A. Types of mutations 1- Point mutations: change in nucleotide pairs 2- Chromosomal mutations: changes in whole genes a. duplication b. deletion c. translocation d. inversion B. Frequency of mutations (1: 200,000)
  7. C. Significance of mutations 1- self diagnostic/repair 2- ultimate source of genetic variation II. Non- Mendelians concepts A. Incomplete dominance B. Co-dominance C. Polygenic inheritance D. Pleiotropy E. Sex-linked inheritance F. Linkage and crossing-over III. Genetic potential and environmental influences A. Mutagenic factors B. Interactions between genetic information and the environment 1- nature 2- significance Vocabulary: chromosomal mutation: crossing-over: codominance: deletion: duplication: incomplete dominance: inversion: linkage: mutation: non-medelian genetics: pleiotropy: polygenic inheritance: sex-linked inheritance: translocation: Study Questions: 1. List, illustrate and discuss the various types of chromosomal mutations. 2. Show how point mutations, in the DNA, can change the sequencing of amino acids in a protein. 3. Distinguish between polygenic inheritance and pleiotropy. 4. Discuss the interactions between genetic information and environmental influences. 5. Show how crossing-over can change linkage patterns in homologous chromosomes.
  8. Types of chromosomal mutations Normal ABCDEFG Deletion ABC EFG D Duplication ABCDCDEFG Inversion ABEDCFG from another chromosome Translocation ABCDEFG XYZ Crossing Over Paired chromosomes (prior to crossover) Paired chromosomes (after crossover) A A A A A A A A b b b b b b b b C C X c c C c C c crossover occurs between genes b&c, Note “C” genes c and C have been thus genes C and c are exchanged switched through crossover Essential information: - a crossover occurs between homologous or paired chromosomes during prophase I of meiosis - a crossover involves an exchange of equal segments of paired chromosomes - a crossover results in the introduction of significant genetic recombination Linked vs Unlinked Genes Unlinked Linked
  9. A a B b A a Parent B b Gametes A B A b A a B b a B a b Inheritance: Human Patterns and Dilemmas I. Discontinuous variation A. Simple dominant-recessive gene interactions in human B. Examples 1- Normal vision dominant over nearsightedness 2- Normal color vision dominant over colorblindness (red-green) 3- Blood types and Rh factor a. A and B are dominant over O b. A and B are co-dominant c. Rh positive is dominant over Rh negative
  10. II. Continuous variation: polygenic inheritance in humans A. Characteristics of polygenic traits 1- Continuous variation or gradation with small differences 2- Variation within a population based on a polygenic trait yields a normal bell curve B. Examples 1- Human height 2- Human intelligence 3- Human skin color (8 alleles for black parent) III. Human genetic potential A. Inherited potential B. Interactions between inherited potential and environmental influences 1- Radiation 2- Chemicals, mutagenic influences 3- Disease 4- Nutritional influences a. protein deficiency b. poverty cycle (malnutrition) IV. Sex- linked inheritance (inheritance patterns associated with genes on the X- chromosome) A. Colorblindness B. Hemophilia V. Nondisjunction A. Sex chromosomes 1- Turner’s syndrome ( 45 x-somes, missing 1 sex x-some, sterile, hard to think abstractly) 2- Klinefelter’s syndrome (one extra X x-some, mentally retarded) 2- Superman syndrome (XYY, approximately 1 in 10000 male births, highly aggressive) B. Autosomes 1- Down’s syndrome (trisomy of x-some 21, males sterile, females low interest, after age 35 for females->frequency increases to approximately 1 in 750 births) Vocabulary: co-dominance: Down’s syndrome: fetus: inherited potential: Klinefelter’s syndrome: malnutrition: non-disjunction: Rh factor: Turner’s syndrome: Study Questions:
  11. 1. List and discuss the basic characteristics of polygenic inheritance in humans. Cite several examples. 2. Show inheritance patterns in the offspring of a father who has normal color vision and a mother who is a carrier for color blindness. Specifically discuss the differential inheritance patterns for this characteristic in the male and female offspring. 3- Explain and illustrate the mechanics of non-disjunction in sex chromosomes. 4- Distinguish between Turner’s and Klinefelter’s disease. 5- Would it be possible for a man who has blood type A to have offspring with blood type O? Show your work (the man’s parents were= father O, mother AB) 6- Is there a possibility for a female to be Rh negative if both her parents are Rh positive? 7- A male has type AB blood and his wife is heterozygous type A. What are the possible blood types of their children?

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