Bio 2230: Chapter 1

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Bio 2230: Chapter 1
2014-09-09 02:15:36
into genetics

Introduction to genetics
Show Answers:

  1. Define genetics.
    scientific study of heredity
  2. why is genetics central to biology?
    because gene activity underlies all life processes
  3. what is classical genetics?
    use of crosses to breed new strains of organisms and to understand how traits are transmitted.
  4. Genetics is often divided into _________ and _________ genetics
    • classical
    • modern
  5. what is an important tool used in classical genetics?
    isolation of mutants affecting particular traits which can then be compared to normal strains
  6. what is modern genetics?
    study of genes at the molecular level
  7. how was the first genetic maps of genes on chromosomes generated?
    classical genetics
  8. how is modern genetics made possible?
    made possible because of advances in cloning and sequencing genes
  9. Modern genetics has provided an enormous understanding of about: (4)
    • physical nature of genes
    • their expression patterns
    • role in development and disease
    • how their products react
  10. what is genomics?
    branch of genetics that studies organisms in terms of their genomes
  11. How are many genes first identified?
    through their effect on phenotype, and then later cloned and sequenced
  12. which organisms have DNA as their genetic material?
    with the exception of some RNA viruses, genetic material of all viruses, prokaryotes and eukaryotes
  13. define genome.
    full DNA sequence of an organism
  14. how is genetic information convey in DNA?
    conveyed in the sequence of nucleotides
  15. what is a gene? what do they encode?
    • segment of DNA bearing a specific sequence of nucleotides
    • encode traits that are passed from parent to offspring
  16. describe the chromosome of a prokaryote and a eukaryote.
    • prokaryote: singular circular chromosome
    • eukaryote: many linear chromosomes within a nucleus
  17. describe the structure of the chromosome.
    single molecule of DNA wrapped around histone proteins
  18. what is the function of histones?
    • allow efficient packing of the genome
    • involved in gene regulation
  19. where do eukaryotes contain extranulear DNA? (2)
    • mitochondria
    • chloroplasts
  20. The laws of inheritance was first created by?
    Gregor Mendel
  21. From his experiment with crosses between pea plants, Gregor Mendel concluded what 2 things?
    • inherited characteristics are determined by genes
    • each organism contains 2 copies of each gene ( one from father, one from mother)
  22. what are alleles? (2)
    • alternative versions of genes
    • account for variations in inherited characteristics
  23. Define homozygous.
    organisms having a pair of identical alleles for a trait
  24. Define heterozygous.
    organisms having 2 different alleles for a gene
  25. Define phenotype.
    observable characteristics of an organism
  26. Define Genotype.
    genetic makeup of an organism
  27. The ________ interacts with the environment (internal and external) to produce the _________.
    • genotype
    • phenotype
  28. What was Mendel's first Law? what was another name for it?
    • members of a gene pair segregate randomly into gametes
    • principle of segregation
  29. What was Mendel's Second Law?
    • different genes assort independently during gamete formation (only applies to genes on different chromosomes or genes that are located very far apart on the same chromosome)
    • principle of independent assortment
  30. what is gene expression?
    process by which a gene produces its product and that product carries out its function
  31. what is the one-gene-one-polypeptide hypothesis?
    genes provide instructions for making proteins (not all proteins are enzymes)
  32. what is transcription?
    process by which a segment of DNA (a gene) is copied into RNA
  33. DNA is locally unwound and ______________ uses one strand as a template to synthesise an RNA copy.
    RNA Polymerase
  34. define rRNA.
    ribosomal RNA: used to make ribosomes (translation machines of the cell)
  35. define tRNA.
    transfer RNA: decode DNA language into protein language by bringing amino acids to ribosomes
  36. define mRNA.
    messenger RNA: specify the amino acid sequences of proteins
  37. define translation. where does is occur?
    • process by which the base sequence of mRNA is converted into an amino acid sequence
    • occurs in ribosomes
  38. what is genetic code?
    base sequence information that specifies the amino acid sequence of a protein
  39. what is a codon?
    three-nucleotide sequence of mRNA that specifies an amino acid
  40. what is a switch regarding the operon model?
    a switch is made up of a protein (transcription factor) whose conformation can be altered by ligand binding and a DNA sequence to which it binds (promoter)
  41. Genetic differences arise through the process of what 3 things?
    • mutation
    • recombination
    • selection
  42. what is mutation?
    change in genetic material (substitutions, deletions, insertions, translocations, etc.)
  43. what is recombination?
    exchange of chromosomal material between homologous chromosomes at meiosis
  44. what is selection?
    over long periods of time, this process leads to a change in frequencies of genes affecting certain traits
  45. All genetic variation ultimately is derived from ________.
  46. Describe the hypothetico-deductive method of investigation.
    • involves making observations about the natural world
    • generating hypothesis to explain observations
    • hypothesis must generate experimental predictions
    • which can be tested under controlled conditions
  47. name the 4 subdisciplines of genetics.
    • transmission (classical) genetics
    • molecular genetics
    • population genetics
    • quantitative genetics
  48. what does transmission (classical) genetics deal with? (2)
    • deals with how genes and genetic traits are inherited
    • how genes recombine (genetic crosses)
  49. what does molecular genetics deal with?
    deals with molecular structure and function of genes (gene expression)
  50. what does population genetics deal with ?
    deals with heredity in groups of individuals for traits that are determined by one or only a few genes
  51. what is quantitative genetics?
    • deals with heredity in groups but the complex traits encoded by many genes simultaneously
    • statistics and genetics
  52. what is the goal of basic research?
    • goal of understanding fundamental phenomena
    • used to fuel more basic research 
  53. what is the goal of applied research?
    goal of overcoming specific problems in society or exploiting discoveries derived from basic research
  54. what does a genetic map do?
    shows the relative locations of genes along a chromosome as well as the distance between genes
  55. what understanding does genetic maps give us?
    understanding of the organization of genes along chromosomes
  56. what are the qualities that make an organisms a good model for genetic experimentation? (5)
    • well known genetic history
    • short life cycle
    • mating produces large amount of offspring
    • easy to handle (genetically traceable)
    • genetic variation between individuals in a population
  57. what is applied genetics?
    genetic screens for metabolic diseases