Thursday, March 13, 2008
Wednes-Day 1
Bio- we discussed MEIOSIS, the process by which gametes (sperm or egg cells) are made. MEIOSIS occurs ONLY to specialized cells in the gonads (the OVARIES of females or the TESTES of males).
In order to produce gametes that can unite (fertilization) the number of chromosomes must first be halved from 46 to 23; meiosis accomplishes this "REDUCTION DIVISION".
We saw that two of the sources of genetic variety among the sex cells produced occurs during later prophase I and during metaphase I. During late prophase I, HOMOLOGOUS PAIRS of chromosomes (chromosomes that code for the same TRAITS/CHARACTERISTICS) come together and overlap in SYNAPSIS (chiasmata); the DNA from one chromatid on one chromosome may be exchanged with the corresponding DNA of a chromatid on its homologous partner's chromosome; this is called "CROSSING OVER".
During metaphase I, the homologous chromosomes line up in PAIRS independently of each other; that means that order of the first pair of homologous chromosomes (left to right or right to left) has NO EFFECT on how any other pair of homologous chromosomes line up. This means that, for humans, which have 23 pairs of homologous chromosomes, that there are 529 ways that the different homologous pairs can line up!
We did a lab graphing activity that organized the data of hormone level variation during the menstrual cycle so that we can see the various negative feedback mechanisms that occur during the cycle.
Chem 7- we did some exercises involving the naming, balancing, and using mole ratios in order to do several stoichiometry calculations.
Going from the magic triangle to the balanced equation and back to the magic triangle gets you to the solution for most stoichiometry problems.
Chem 8/9- we did some exercises involving the naming, balancing, and using mole ratios in order to do several stoichiometry calculations.
Going from the magic triangle to the balanced equation and back to the magic triangle gets you to the solution for most stoichiometry problems.
We did a stoichiometry lab in which we produced a sodium salt (NaCl) from a different sodium salt (NaHCO3). Using the balanced equation and our lab data, we can show the mole ratio of these two substances in this reaction.
In order to produce gametes that can unite (fertilization) the number of chromosomes must first be halved from 46 to 23; meiosis accomplishes this "REDUCTION DIVISION".
We saw that two of the sources of genetic variety among the sex cells produced occurs during later prophase I and during metaphase I. During late prophase I, HOMOLOGOUS PAIRS of chromosomes (chromosomes that code for the same TRAITS/CHARACTERISTICS) come together and overlap in SYNAPSIS (chiasmata); the DNA from one chromatid on one chromosome may be exchanged with the corresponding DNA of a chromatid on its homologous partner's chromosome; this is called "CROSSING OVER".
During metaphase I, the homologous chromosomes line up in PAIRS independently of each other; that means that order of the first pair of homologous chromosomes (left to right or right to left) has NO EFFECT on how any other pair of homologous chromosomes line up. This means that, for humans, which have 23 pairs of homologous chromosomes, that there are 529 ways that the different homologous pairs can line up!
We did a lab graphing activity that organized the data of hormone level variation during the menstrual cycle so that we can see the various negative feedback mechanisms that occur during the cycle.
Chem 7- we did some exercises involving the naming, balancing, and using mole ratios in order to do several stoichiometry calculations.
Going from the magic triangle to the balanced equation and back to the magic triangle gets you to the solution for most stoichiometry problems.
Chem 8/9- we did some exercises involving the naming, balancing, and using mole ratios in order to do several stoichiometry calculations.
Going from the magic triangle to the balanced equation and back to the magic triangle gets you to the solution for most stoichiometry problems.
We did a stoichiometry lab in which we produced a sodium salt (NaCl) from a different sodium salt (NaHCO3). Using the balanced equation and our lab data, we can show the mole ratio of these two substances in this reaction.
# posted by C @ 1:11 PM 
