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Genetics

Genetics. ( Part One). By Group 3. Name: Poon Wing Ching (Prudence) Tse Man Ki (Annie) Wong Chi Yin (Stanley). Contents. Revision & Introduction. What is Genetics?. What determines our characteristics?. Summary. Self-learning Exercises. Revision on Reproduction. True or False.

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Genetics

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  1. Genetics (Part One) By Group 3 Name: Poon Wing Ching (Prudence) Tse Man Ki (Annie) Wong Chi Yin (Stanley)

  2. Contents Revision & Introduction What is Genetics? What determines our characteristics? Summary Self-learning Exercises

  3. Revision on Reproduction True or False Q1. Pollen grains are the male gametes. True False

  4. Revision on Reproduction True or False Q2. In flowering plants, ovaries will develop into seed True False

  5. Revision on Reproduction True or False Q3. Gardeners sometimes use seeds to produce new plants for flowers because this method has an advantage of preventing overcrowding as compared with vegetative propagation. True False

  6. Revision on Reproduction True or False Q4. The umbilical cord is a structure for attachment of the embryo to the uterine wall. True False

  7. Right, you are correct!!! • Pollen grains are the carries of male gametes

  8. Right, you are correct!!! • In flowering plants, ovaries will develop into fruits, whereas the ovules will develop into seeds.

  9. Right, you are correct!!! • Prevention of overcrowding is an advantage for plant dispersal only. Gardeners using seeds to produce new plants of flower, because this method can produce variations which may give rise to flowers of better quality. Such an advantage is not found in vegetation propagation.

  10. Right, you are correct!!! • The umbilical cord connects the embryo to the placenta instead of the uterus.

  11. Sorry, you’re wrong!!! Pollen grains are the carries of male gametes

  12. Sorry, you’re wrong!!! In flowering plants, ovaries will develop into fruits, whereas the ovules will develop into seeds.

  13. Sorry, you’re wrong!!! Prevention of overcrowding is an advantage for plant dispersal only. Gardeners using seeds to produce new plants of flower, because this method can produce variations which may give rise to flowers of better quality. Such an advantage is not found in vegetation propagation.

  14. Sorry, you’re wrong!!! The umbilical cord connects the embryo to the placenta instead of the uterus.

  15. Introduction • Can you guess who is the son of Mr. Simpson ? • Do you look like your parents? :-) Why do we resemble our parents?

  16. What is genetics(遺傳學)? • The study of how characteristics are passed from generation to generation.

  17. What determines our characteristics? • Gene, DNA & Chromosomes Genes(基因): • basic unit of heredity • present on chromosome • Genes are short lengths of DNA on chromosome

  18. Gene, DNA & Chromosomes (Cont’d) • determine the sequences of amino acids Genes:(Cont’d) • controls protein synthesis • Indirectly controls the appearance of characters and metabolic activities of an organism

  19. Gene, DNA & Chromosomes (Cont’d) • DNA (Deoxyribose nucleic acid 去氧核糖核酸) • genetic material determining body characters by controlling types of protein produced

  20. Gene, DNA & Chromosomes (Cont’d) Chromosome(染色體): • genetic materials found inside the nucleus of the cell • one from female parent • made of protein & DNA • each kind of organism has a specific no. of chromosome e.g. man:46 • exist in pairs in body cell • the members of each pair of chromosome is called Homologous chromosomes • one from male parent

  21. The role of gametes • As vehiclesof inheritance Fusion of a male & female gametes  zygote  organism

  22. How gametes are formed? • by the process meiotic cell division • The major task of meiosis is to produce haploid gametes • in the process of meiosis, crossing over can occur

  23. Meiosis(減數分裂) Meiotic cell division including meiosis and division of cytoplasm Quicktime Movies of Stages in meiotic cell division: First meiotic division Second meiotic division

  24. Significance of meiosis • Halving of chromosome no.: • producing gametes which have different genetic make - up • The no. of chromosome can be restored at fertilization • think of what would happen if human gametes were produced by mitosis? • Independent assortment of chromosomes:

  25. Mitosis Vs Meiosis Questions on comparing meiotic & mitotic cell divisions: 1. Occurrence 2. Pairing of homologous chromosomes 3. Separation of homologous chromosomes 4. Number of division 5. Number of daughter cells produced from each parent cells 6. Type of daughter cells 7. Chromosome number of daughter cells 8. Function

  26. Summary 1. Gametes are formed by meiosis. (reduction division) 2. Meiotic cell division includes pairing and separation of homologous chromosomes, separation of chromatids and formation of four daughter cells 3. Meiotic cell division is significant in: A.) forming haploid gametes, so diploid number of chromosomes can be restored at fertilization B.) producing gametes which have different genetic make-up

  27. Wrong Concepts 1. Meiosis is a kind of cell division. Meiosis involves division of nucleus alone. This is only a kind of nuclear division. Cell division includes cytoplasmic and nuclear division. 2. Every characteristic is controlled by a pair of genes. Many characteristics are controlled not by one of genes, but by many genes, e.g. height of man.

  28. Self-Learning Exercise Q1: What is the name for the process of fusion of male and female gametes? A. Gametogenesis B. Implantation C. Pregnancy D. Fertilization

  29. Sorry, you’re wrong!!! Gametogenesis: gamete production Try again!!!

  30. Sorry, you’re wrong!!! Implantation: event during fertilized egg becomes embedded in uterine wall Try again!!!

  31. Sorry, you’re wrong!!! Pregnancy: having in the uterus offspring in a stage of development before birth Try again!!!

  32. Congratulations!!! Fertilization: union of male (sperm) and female (egg) gametes You’ve got the correct answer! Next

  33. Self-Learning Exercise Q2: How gametes are formed? A. Meiotic cell division B. Meiosis C. Mitosis D. Mitotic cell division

  34. Congratulations!!! Gametes are formed by a process called meiotic cell division, including meiosis and division of cytoplasm Next

  35. Sorry, you’re wrong!!! Meiosis is a kind of nuclear division. Try again!!!

  36. Sorry, you’re wrong!!! Mitosis is a kind of nuclear division for increasing no. of cell Try again!!!

  37. Sorry, you’re wrong!!! Mitotic cell division including mitosis and cytoplasm division Try again!!!

  38. Self-Learning Exercise Q3: Inherited characteristics are determined by? A. DNA B. Chromosomes C. Genes D. Proteins

  39. Sorry, you’re wrong!!! DNA provides the genetic information to control protein synthesis Try again!!!

  40. Sorry, you’re wrong!!! Chromosome carries genes Try again!!!

  41. Congratulations!!! Inherited characters are determined by genes Go to End

  42. Sorry, you’re wrong!!! Proteins control body characteristics and metabolic activities Try again!!!

  43. Further Reading Science Learning Network Biological Science Page

  44. The End

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