Card Set Information

2015-09-18 21:56:53

Show Answers:

  1. Explain the inheritance of traits which are determined by one or more
    genes, including dominance, recessive, sex linkage, phenotypes,
    genotypes and incomplete dominance
    dominance - if two alleles of an inherited pair differ, determines the organism's

    • appearance recessive - has no noticeable effect on the organism's appearance
    • phenotype - physical traits

    genotype - genetic makeup

    sex linkage - a gene located on a sex chromosome

    incomplete dominance - an appearance between the phenotypes of the two parents
  2. Solve problems that illustrate monohybrid and dihybrid crosses
    monohybrid - a mating of individuals differing at one genetic locus

    dihybrid - a mating of individuals differing at two genetic loci
  3. Compare sexual and asexual reproduction
    • sexual:
    • creation of offspring by the fusion of gametes

    increases genetic variability

    • asexual:
    • offspring are genetically identical to lone parent

    no need for mate

    quicker and less energy in the production of gametes

    produces genetically uniform populations
  4. Explain how the coding of DNA controls the expression of traits by genes
    the sequence of nucleotide bases in DNA contains 3-base codons that code for amino acids for protein synthesis

    traits arise from the actions of a wide variety of proteins
  5. Define mutations and explain their causes
    any change in the nucleotide sequence of DNA

    caused by errors during DNA replication or recombination

    chemical or physical mutagens
  6. Explain the process of DNA replication
    begins at origins of replication

    semi-conservative - two strands of parental DNA separate and each becomes a template for the assembly of a complementary strand from a supply of free nucleotides

    the nucleotides are lined up one at a time along the template strand in accordance to base pairing rules

    enzymes link the nucleotides to form the new DNA strands
  7. Relate the structure and function of DNA, RNA and proteins to the concept of variation in organisms
    DNA is a double helix and stores information

    RNA is single stranded and carries the information or acts as a messenger

    the information is transformed into proteins which perform most of the functions of cells, proteins come in many different structures according to their function
  8. Describe chromosome structure as a sequence of genes each with a specific locus
    a locus is the specific location of a gene on a chromosome
  9. Explain the necessity of both meiosis and fertilization in promoting variation
    independent assortment - large number of possible arrangements  of chromosome pairs at metaphase of meiosis I leads to many different combinations of chromosomes in gametes

    random fertilization of gametes greatly increases variation

    crossing over during prophase of meiosis I also increases variation
  10. Describe the role of chromosomes in determining phenotypes (eg sex determination, chromosomal aberrations)
    one chromosome comes from each parent and the genes on those chromosomes determine phenotype

    • chromosomal abberations occur when there is an abnormal number of chromosomes or
    • abnormality in a chromosome, usually occur from errors in mitosis or meiosis
  11. Predict the probable outcome of phenotypes in a genetic cross from the
    genotypes of the parents and mode of inheritance (eg autosomal or
    X-linked, dominant or recessive, co-dominance)
    autosomal - gene is on any chromosome that is not a sex chromosome

    X-linked- gene is located on X chromosome, if gene is recessive females will  only have trait if they carry two copies of allele, males only need to carry a single copy of the recessive allele to show trait

    dominant or recessive - dominant phenotype in heterozygote

    co-dominance - both dominant alleles are expressed in heterozygote
  12. Explain the genetic and cellular bases for Mendel's laws of dominance, segregation and independent assortment
    segregation - a sperm or egg carries only one allele for each inherited character because the two members of an allele segregate from each other during the production of gametes

    independent assortment - each pair of alleles assorts independently of the other pairs of alleles during gamete formation
  13. Explain how random chromosome segregation explains the probability that a particular allele will be in a gamete
    chromosomes are randomly segregated into 4 gametes during meiosis

    there is a 1/4 chance that a particular allele will be in a gamete
  14. Recognize that specialization of cells in multicellular organisms is
    usually due to different patterns of gene expression rather than to
    differences among the genes themselves
    gene regulation turns on certain genes in cells which allows them to develop into cells ith different structures and functions
  15. Describe how alleles that are lethal in a homozygous individual may be
    carried in a heterozygote and thus maintained in a gene pool
    allele may be recessive and so is not lethal in individuals that are heterozygous
  16. Distinguish when and why mutations in the DNA sequence of a gene may or
    may not affect the expression of the gene or the sequence of amino acids
    in an encoded protein
    silent mutation - because of redundancy of genetic code, some substitution mutations have no effect if the base change results in the same amino acid being made

    missense mutation - change of single base changes the amino acid codon

    nonsense mutation - base substitution changes the amino acid codon to a stop codon

    insertion or deletion of bases can cause all downstream bases to be read incorrectly
  17. Recognize how genetic engineering (biotechnology) produces biomedical and agricultural products
    genetic engineering is the direct manipulation of genes for practical purposes

    by transferring the gene for a desired protein into a bacterium or other kind of cell that is easy to grow in culture, scientists can produce large quantities of proteins that are present naturally in only small amounts

    in agriculture scientists have produced GMOs that have acquired new genes by artificial means to improve the productivity of important plants and animals
  18. Describe the construction of recombinant DNA molecules by basic DNA
    technology including restriction digestion by endonucleases, gel
    electrophoresis, ligation and transformation
    • perform restriction digestion by endonucleases to cut DNA into fragments
    • verify success of digestion by seaparating the different DNA fragments using gel electrophoresis

    combine DNA fragments using ligation enzyme

    prepare for transformation to incorporate recombined DNA
  19. Discuss issues of bioethics including genetic engineering, cloning, the
    human genome project, gene therapy and medical implications
    Along with new DNA technology comes new potential dangers

    children with SCID were cured using gene therapy, but 4 children developed leukemia from the treatment

    concerns about creating new dangerous disease causing organisms

    guidelines and safety precautions are taken

    controversy over the safety of GMOs, may be harmful to environment or humans

    legal and ethical questions are raised, privacy issues

    information about disease associated genes could be abused and lead to discrimination