bio chapter 11

• the process of producing egg cell and sperm cells is called :

  meiosis
• in egg cells and sperm cells, the chromosomes are located in what organelle of the cell?

  ovaries and testes
• what is fertalization ?

  union if two nuclei of both ( n+n=2n)
• zygote divide by :

  mitosis
• what are the two types of chromosomes in men?

  1. autosomes

  2. sex chromosomes
• which type of chromosome is involved in sex determination?

  sex chromosomes
• What are the two types of sex chromosomes?

  1. X chromosome

  2. Y chromosome
• how many sets of chromosomes are there in a human somatic cell?

  2 sets = 46 chromosomes

  44 autosomes, 22 pairs of autosomes
• how many chromosomes are there in a human somatic cell? how many of them are coming from the father and how many come from the mother?

  46 chromosomes= 23 from father, 23 from mother
• of the 46 chromosomes in humans, how many are autosomes? how many are sex chromosomes

  44 autosomes

  2 sex chromosomes ( 1 pair)

  44+xx=46 ( female)

  44+xy=46( male)
• how many sets of chromosomes are there in a human gametes

  1 set, n=23, haploid
• how many autosomes and sex chromosomes are there in human sperm cell

  22 autosomes + x or y=23sperm can carry either x or y
• describe how a 44+ xx zygote is produced?


  egg cell ( n) + sperm cell ( n) = zygote ( 2n)

  ( 22+x) ( 22+ y) ( 44+ xy) --> male
• what is meiosis?

  division of the nucleus
• reduction division in which the number of chromosomes per cell is cut in _____

  Half 2n-->n
• it involves divisions producing a total of _____ daughter cells

  2; 4
• meiosis occurs in what organ?

  females: in the ovaries in the process called oogenesis

  males: in the testes in the process called spermatogenesis
• ogensis:

  the cells in the ovary that are destined to become egg cells are called oogonium. Are they diploid or haploid? How many chromosomes are there?

  diploid; 46 chromosomes
• in females, meiosis 1 occurs during :

  in the womb, prophase 1 already occurs but then break untill puberty
• meosis II occurs only when there is:

  fertilization ( needs sperm cell)
• Spermatogenesis

  the cells in the testis that are destined to become sperm cells are called _____ are they diploid or haploid? how many chromosomes are there?

  spermatogonium; diploid; chromosomes

  - forms 4 spermatids ( haploid, n)
• what stage come before meiosis I? what events occur during this stage?

  -interphase = G1, S, G2

  - growth

  - DNA synthesis

  - other preparations for cell division
• meiosis I

  1. prophase

  2. metaphase 1

  3. anaphase 1

  telophase 1/ cytokinesis

  no interphase before meiosis II
• what are the four phases of meiosis II

  1. prophase II

  2. metaphase II

  3. anaphase II

  4. telophase II & cytokinesis
• homologous chromosomes

  same size and same shape
• What is pair of homologous chromosomes

  - one from mother and other from father

  - diff colors but same size

  - we have 23 pairs ( one from mom and one dad)