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Flashcards

Biology

Maria Valle English 38 cards

Cards in this deck (38)

  1. 1What is a gamete?the entire genetic complement (DNA) of an organism; sperm and eggs are haploid due to meiosis and they combine through fertilization to make a diploid, or zygote
  2. 2what is the basic difference between an autosome (somatic) chromosome and a sex chromosome?Autosome: not sex chromosomes; truly homologous; each member of a pair contains a full complement of the same gene; determine the traits of the organism
    Sex Chromosome: X and Y; determine the sex of the orgamism
  3. 3What is a homologous chromosome?*two copies of the each autosome
    *the 2 chromosomes of a homologous pair are independent chromosomes that were inherited from different parents, may contain different versions of the same gene
  4. 4What is the difference between a diploid (2n) and Haploid (1n)?Haploid: 1 copy each chromosome
    one sex chromosome; reproductive cell
    Diploid: 2 copies each
    two sex chromosomes
    not reproductive cells
    somatic cells are diploids because they divide by mitosis
  5. 5What is the basic purpose of Meiosis I? Meiosis II?Meiosis I: Reduction division, each chromosome consists of two strands of sister chromatids connected at the centre
    Meiosis II: to reduce chromosomes # because fertilization will double it; genetic variation DNA is not copied
  6. 6What is being accomplished in Meiosis?making new gametes for sexual reproduction
  7. 7What is crossing over and when does is take place?Crossing over alters the composition of chromosomes and results in new combinations of alleles being channeled into the daughter cells; occurs in
    prophase I
  8. 8At what stage do the homologous chromosomes randomly line up in the center of the cell?Metaphase I
  9. 9The three main sources of genetic variability in the offspring that occur during meiosis?1. crossover-prophase I
    2. homologous chromosome line up-metaphase I
    3. random fertilization by the unique egg and sperm
  10. 10What are the basic steps of Meiosis?Meiosis I: prophase I
    Metaphase I
    Anaphase I
    Telophase I and cytokinesis
    Meiosis II: Prophase II
    Metaphase II
    Anaphase II
    Telophase II and cytokinesis
  11. 11How many daughter cell are formed at the end of Meiosis I and Meiosis II?Meiosis I: 2
    Meiosis II: 4
  12. 12What is a karyotype?Photomichrograph of dividing cell chromosomes used to identify
  13. 13who determines the sex of the baby and why?Females are XX and Males are XY; the male determines the sex because of the Y chromosome
  14. 14What is Trisomy 21 and what causes it?the most common form of Down Syndrome, caused by an extra copy of chromosome number 21; cannot be inherited; risk increases with age of the mother; physical appearance: wide spaced eyes that slightly slant, small hands; 50% of people born with Down Syndrome will develop heart problems
  15. 15what is nondisjunction?an error in cell division; the failure of homologous chromosomes to separate properly, causing daughter cells not to have the proper number of chromosomes
  16. 16What is Klinefelter Syndrome?an extra X chromosome in boys/men-often due to paternal rather than maternal disjunction (XXY); affects i in 500 males Behavioral problems; in maturity insecurity; developmental delays physical findings: gynecomastia, hypogonadism, long limb
  17. 17What is Turner's Syndrome?*Chromosomal condition that affects development in females,
    *occurs in about 1 in 2500 newborn girls
    *related to X chromosome, which is one of two sex chromosomes, one X chromosomes is present in a females cells and the other sex chromosome is missing or structurally altered
    *not inherited
    *rarely Turner Syndrome caused by partial deletion of the X chromosome can be passed from generation to the next
  18. 18What is deletion?a mutation in which a section of the DNA is lost or deleted
    exm: Crid Du Chat
  19. 19What is duplication?A mutation in which a section of DNA is duplicated and both copies end up in the same chromosome. Can occur because of an error during the duplication process of meiosis
    Exm: cancer
  20. 20What is inversion?A mutation in which a section of DNA is put in backwards
  21. 21What is Insertion?A mutation in which extra base pairs, are inserted into DNA sequence.
  22. 22What is reciprocal translocation?mutation in which two non-homologous chromosomes exchange sections of DNA
  23. 23Who is the father of genetics? What did he experiment with?Gregor Mendol
    Investigated inheritance at the organism level
  24. 24define traitcharacteristics that are passed on from parent to offspring
  25. 25define homologous pairsboth members have same length and centromere location; both carry the same genes for the same traits in the same order
  26. 26define allelesalternate forms of a gene expressed in letters: capital or lower case
  27. 27what is homozygous?gene combination involving 2 dominant or 2 recessive genes
    WW: Dominant homozygous
    ww: recessive homozygous
  28. 28what is heterozygous?gene combination of one dominant and one recessive allele
    Rr: also called hybrid
  29. 29What is dominant?Stronger if two genes expressed in the hybrid; represent by a capital letter
  30. 30What is recessive?gene that shows up less often in a cross; represented by a lower case letter
  31. 31GenotypeTypes of genes
    Alleles the chromosomes carry that are responsible for a given trait (RR, Rr, rr)
    Two alleles for a trait, one on each chromosomes
  32. 32Phenotypeindividuals' actual appearance (color, height, etc) physical expression of the trait
  33. 33Pedigreea graphic representation of genetic inheritance: a diagram made up of symbols that identify males and females; individuals affected by the trait being studied; and family relationship; to see who is a carrier for a genetic disorder
  34. 34what is sickle cellred blood cells are sickle shaped due to abnormal hemoglobin; differs from normal hemoglobin by one amino acid; autosomal recessive disorder
  35. 35what is cystic fibrosis?most common lethal genetic disorder among Caucasians in the US, chloride ions fail to pass through a plasma membrane channel protein in cells; causes abnormally thick mucus in bronchial tubes and pancreatic ducts; autosomal recessive disorder
  36. 36what is huntington's diseaseNeurological disorder that leads to progressive degeneration of the brain cells; caused by a mutated copy of gene for a protein called huntington; most patients appear normal until they are of middle age and have already had children; autosomal dominant disorder
  37. 37What is codominance?Occurs when alleles are equally expressed in a heterzygote
    blood type AB is an example
    red blood cells have both Type A and B surface antigens
  38. 38In blood typing, which is the universal donor? which type is the universal recipient?O-
    AB+

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Flashcards on Biology, created by Maria Valle on 15/11/2017.
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Maria Valle
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