Review General Biology 1

Chapter 12 Patterns of Inheritance

  1. Define Locus, loci, allele, homologous, homolog, sister chromatid, homozygous, heterozygous. What is the difference between homozygous and homologous?

  2. Who was Gregor Mendel. When did he live, where did he live? What did he study. How did mathematics shape his studies?

  3. Define ‘fertilization’ of plants, self-fertilizing, True Breeding.

  4. How did Mendel CHOOSE the right things? How is this similar to the scientific method?

  5. Why was the ‘edible pea’ the ‘right’ organism? How did he design his experiments correctly? How did studying individual traits w/ unmistakable characteristics facilitate his studies and conclusions? What did ‘meticulous’ records do for his work? He ‘quantified his results – what does this mean?

  6. Define P, F1, F2, and F3. How did Mendel use these? Which were homozygous? Explain. What is meant by ‘self-pollinate’?

  7. What is meant by the 3:1 ratio? Define phenotype and genotype.

  8. Now, what was the actual phenotype of the 3:1 ratio of the F2 generation?

  9. Define Dominant trait vs Recessive trait.

  10. What is the 5 part hypothesis – list the 5 parts – what does each mean?

    1. Each trait is determined by pairs of discrete physical units we now call GENES.

    2. Law of segregation – the alleles on Homologs separate during sexual reproduction

    3. Chance governs which allele gets included in the gamete

    4. In Heterozygous organisms – the dominant allele MAY mask the recessive allele. The dominant does NOT change the recessive, merely ‘hides’ it.

    5. True-breeding organims are Homozygous; Hybrids are Heterozygous.

    11.

  11. How is a ‘gene’ concept obtained from this info?

  12. What is the Law of Segregation?

  13. Define ‘chance’ and ‘random’? What role does ‘chance’ play? What role does ‘random’ play.

  14. If an organism is heterozygous, what does this mean w/ respect to it’s phenotype and genotype?

  15. Now- which parent’s (Mother or Father) gametes contain the Dominant allele? Explain why?

  16. Explain the Punnett square. Using height – T = tall, and t=short; construct a Punnett square. Show ALL the possible combinations.

  17. How can the Punnett square be used to PREDICT the outcome of various crosses?

  18. What is a ‘test cross’?

  19. What is the ‘law of independent assortment’? How would YOU reword it so that it makes sense to you? How is it related to ‘multiple traits’?

  20. What did Mendel do that led him to his Law of Independent Assortment?What did he study?

  21. Construct a Punnett square for TWO traits: height T, t and eye color B=Brown, and b=blue.

  22. Remember Meiosis? How about Meiosis 1 – what are the stages? What happens in each? What happens in Metaphase 1? What determines which way the homologs face? Describe in detail. What does ‘random assortment’ mean? What role does ‘chance’ play?

  23. Define Genetic Linkage

  24. How many genes does each chromosome contain? What happens to each of these genes during meiosis?

  25. How is this the ‘bean counter’ answer?

  26. Define Crossing Over, Recombination, chiasmata. How does this affect the ‘bean counter’ answer? What happens to sister and non-sister chromatids during prophase 1? What happens if sister chromatids ‘cross over’? why? Explain in detail. How does ‘recombination’ result in 4 distinct gametes? Show this in a Punnett square or other diagram.

  27. How is Sex(Gender) determined? How are Sex-linked genes inherited? What is meant by ‘sex’ in this case?

  28. Define Autosomes.

  29. Describe the ‘sex chromosomes’ of most animals and insects.

  30. How is the gender of the zygote determined? Males are heterozygous for gender – females are homozyous.

  31. In the male, what is the ratio of gender in the gametes? Why? Explain this w/ respect to being heterozygous for gender vs heterozygous for hair color.

  32. How is a gene’s locus associated w/ sex-linked?

  33. How many genes does the human Y chromosome have? The X chromosome? List some x-linked genes. Are they dominant or recessive?

  34. What happens to the female phenotype with respect to genes w/ loci on the sex chromosomes? Why?

  35. What happens to male phenotype with respect to genes w/ loci on the sex chromosomes? Why?

  36. How would you ‘make’ a Punnett square w/ a sex-linked gene?

  37. What happens to gene expression in NATURE?

  38. Define Incomplete dominance. Give an example.

  39. Where do Alleles come from? What is the condition of the individual w/ respect to an allele? What is the condition of the population? Why?

  40. Give some examples of multiple alleles in a population.

  41. What is meant by "Polygenic inheritance" ?

  42. How does ‘polygenic inheritance’ lead to ‘variation’ in a population?

  43. Define pleitropy, SRY gene. What does SRY gene do? How does the SRY gene make a male heterozygous?

  44. How does the environment influence the genotype? The fur color of a Himalayan rabbit?

  45. Skin color, height, Intelligence, etc how can these be EXTRAPOLATED to other personality traits? Such as musical ability, athleticism.

  46. How are Human Disorders, that are caused by single genes, inherited?

  47. List some of the characteristics that are caused by single genes.

  48. Define Homeostasis – now how are GENES linked to homeostasis?

  49. How can a mutation can impair or destroy enzyme function?

  50. How can a single functional allele ‘mask’ a non-functional allele? How is the phenotype related to this?

  51. When are the recessive alleles expressed in individuals?

  52. What do you call a Heterozygous individuals?

  53. Define Geneticist, genetic disease. What do they estimate about the number of genes that we each carry that could cause genetic disease?

  54. Why are unrelated organisms UNLIKELY to produce offspring with a genetic defect? What is the ‘chance’ that relatives will produce an offspring with a genetic defect? WHY does the chance increase?

  55. Define albinism, sickle cell anemia – what causes em?

  56. If a genetic disease is Dominant – what happens to the parent and offspring? How many Dominant and Recessive genes are listed on the On-Line Mendalian Inheritance in Man database? If a disease gene is Dominant, how is it passed on to the offspring?

  57. What happens if a non-dominant disease parent pass a Dominant genetic disease gene to his offspring?

  58. How can mutations cause genetic disease?

  59. If a trait is controlled by a single gene, how many alleles for that trait can an individual have?

  60. Explain how an abnormal protein can interfere w/ the normal protein.

  61. How can a ‘new’ protein produce NEW, TOXIC rxns?

  62. How is Homeostasis maintained?

  63. Define feedback mechanism and list the two types, and some examples of each. How can a defective gene interfere with these feedback mechanisms?

  64. Where are the loci for recessive sex-linked genes? Why do these often ‘skip’ a generation?

  65. List some recessive genetic diseases.

  66. Define Nondisjunction of chromosomes. What happens in this case? WHERE/when does it occur? What part of Meiosis has to malfunction?

  67. How do errors in chromosome number affect humans?

  68. How does Nondisjunction arise? Which chromosomes are affected by Nondisjunction?

  69. How is meiosis associated with ‘nondisjunction’?

  70. Define ‘spontaneous abortion’.

  71. What happens to MOST embryos w/ an abnormal chromosome number? Why?

  72. List some diseases associated with Nondisjunction of Sex chromosomes.

  73. In sperm (male), egg (female). What are the names and the chromosome number? Why are so few embryos that lack an x chromsome born?

  74. What happens when a nondisjunction sperm fuses to a normal egg? Or a nondisjunction egg with a normal sperm?

  75. List some genetic diseases associated with Nondisjunction of the Autosomes. What does Nondisjunction of the Autosomes mean? What is the name, what is the chromosome affected? How? How does AGE affect nondisjunction? Why? How much ‘nondisjunction is attributed to the father/sperm? Why do you think the discrepancy exists?

  76. Why are the majority of Down Syndrome children born to young parents? Link this to the activities of young people.

 

Homework/extra credit:

  1. Your book states that XXY and XXX affects ca 1/1000 males and females respectively but in the US there are only about 134k. What is the potential number of XXX or XXY? Why are there so ‘few’?

  2. Also, XO affects 1/3000 females but only about 100k in US. What is the potential number of XO? Why are there so ‘few’?

  3. Define each, and give examples.

    1. Mutagen

    2. Teratogen

    3. Carcinogen.

  4. Find an MSDS for each of the following, what is it, where is it used, and is it a mutagen, teratogen, or carcinogen.

    1. Thalidamide

    2. Dioxin

    3. Ethanol

    4. UV radiation

    5. Cannabis

    6. Nicotine