Wednesday, March 26, 2008
Tues-Day 1
Welcome back from vacation! I hope that you are refreshed!
Bio- we began our Genetics unit by discussing the work and discoveries of Gregor Mendel. By naturally following the tenets of properly designed scientific experiments and statistical analysis, Mendel was able to show how traits are passed on from parent to offspring. He called the inheritable factors "genes" and he detailed how they are passed from parent to offspring.
His main observations are summarized in the Law of Dominance, the Law of Segregation and Recombination, and the Law of Independent Assortment.
We saw that the genes for certain traits can come in two or more forms/alleles. From Mendel's experiments, he saw that typically one allele DOMINATES (shows up in offsprings' phenotype) over the other (recessive) allele. He also showed, based on the percentage of offspring with a specific phenotype, that the alleles (within a given parent) segregate/separate as the sex cells are made; we now know that this occurs during anaphase II of meiosis as the chromatids, each carrying one allele per gene) are pulled apart and go to separate sex cells.
Alleles are then "recombined" when the diploid number of chromosomes is restored via fertilization of an ovum by a sperm to form a zygote.
We discussed the difference between GENOTYPE and PHENOTYPE. Genotype refers LITERALLY to the specific alleles that an individual has for a given trait.
For genes that have only two alleles, one dominant and one recessive, there are THREE possible GENOTYPES:
HOMOZYGOUS DOMINANT, e.g. TT
HETEROZYGOUS, e.g. Tt or tT (hetero means different; this type has two DIFFERENT alleles)
HOMOZYGOUS RECESSIVE, e.g. tt
A PHenotype is what you PHysically SEE expressed by the organism! In order to have the recessive alleles appear physically (expressed physically), an organism MUST have the homozygous RECESSIVE GENOTYPE, otherwise, BY DEFINITION, the dominant allele will be expressed in the phenotype INSTEAD of the recessive allele.
Therefore, a Tt or a TT GENOTYPE will be expressed as the "TALL" PHENOTYPE (you can SEE the tall characteristics even though you can't physically see the genes that cause the phenotype). However, a "tt" genotype will form/be expressed as the "SHORT" PHENOTYPE.
Chem 7- we began our new unit on Equilibrium. The initial main point to know is the STRICT DEFINITION of equilibrium. Equilibrium can ONLY and ALWAYS refer to the equal RATES of forward and reverse (CHEMICAL) reactions or (PHYSICAL) processes. It is AS IMPORTANT to know that, at EQUILIBRIUM, the amounts/quantities/concentrations of the "reactants" are NEVER EQUAL to the amounts/quantities/concentrations of the "products" (no matter what)!!!
Equilibrium is reached when the amounts/quantities/concentrations of the reactants and products STAY CONSTANT! These quantities must logically stay constant because the reactants and products are being used up AND formed at the same time and at the same RATE. Thus, the reaction NEVER STOPS but the amounts/quantities/concentrations of all particles remains constant at equilibrium. Since the reaction continues forever, equilibrium is DYNAMIC.
Chem 8/9- we began our new unit on Equilibrium. The initial main point to know is the STRICT DEFINITION of equilibrium. Equilibrium can ONLY and ALWAYS refer to the equal RATES of forward and reverse (CHEMICAL) reactions or (PHYSICAL) processes. It is AS IMPORTANT to know that, at EQUILIBRIUM, the amounts/quantities/concentrations of the "reactants" are NEVER EQUAL to the amounts/quantities/concentrations of the "products" (no matter what)!!!
Equilibrium is reached when the amounts/quantities/concentrations of the reactants and products STAY CONSTANT! These quantities must logically stay constant because the reactants and products are being used up AND formed at the same time and at the same RATE. Thus, the reaction NEVER STOPS but the amounts/quantities/concentrations of all particles remains constant at equilibrium. Since the reaction continues forever, equilibrium is DYNAMIC.
We then did a lab activity that is ANALOGOUS to an equilibrium process.
Bio- we began our Genetics unit by discussing the work and discoveries of Gregor Mendel. By naturally following the tenets of properly designed scientific experiments and statistical analysis, Mendel was able to show how traits are passed on from parent to offspring. He called the inheritable factors "genes" and he detailed how they are passed from parent to offspring.
His main observations are summarized in the Law of Dominance, the Law of Segregation and Recombination, and the Law of Independent Assortment.
We saw that the genes for certain traits can come in two or more forms/alleles. From Mendel's experiments, he saw that typically one allele DOMINATES (shows up in offsprings' phenotype) over the other (recessive) allele. He also showed, based on the percentage of offspring with a specific phenotype, that the alleles (within a given parent) segregate/separate as the sex cells are made; we now know that this occurs during anaphase II of meiosis as the chromatids, each carrying one allele per gene) are pulled apart and go to separate sex cells.
Alleles are then "recombined" when the diploid number of chromosomes is restored via fertilization of an ovum by a sperm to form a zygote.
We discussed the difference between GENOTYPE and PHENOTYPE. Genotype refers LITERALLY to the specific alleles that an individual has for a given trait.
For genes that have only two alleles, one dominant and one recessive, there are THREE possible GENOTYPES:
HOMOZYGOUS DOMINANT, e.g. TT
HETEROZYGOUS, e.g. Tt or tT (hetero means different; this type has two DIFFERENT alleles)
HOMOZYGOUS RECESSIVE, e.g. tt
A PHenotype is what you PHysically SEE expressed by the organism! In order to have the recessive alleles appear physically (expressed physically), an organism MUST have the homozygous RECESSIVE GENOTYPE, otherwise, BY DEFINITION, the dominant allele will be expressed in the phenotype INSTEAD of the recessive allele.
Therefore, a Tt or a TT GENOTYPE will be expressed as the "TALL" PHENOTYPE (you can SEE the tall characteristics even though you can't physically see the genes that cause the phenotype). However, a "tt" genotype will form/be expressed as the "SHORT" PHENOTYPE.
Chem 7- we began our new unit on Equilibrium. The initial main point to know is the STRICT DEFINITION of equilibrium. Equilibrium can ONLY and ALWAYS refer to the equal RATES of forward and reverse (CHEMICAL) reactions or (PHYSICAL) processes. It is AS IMPORTANT to know that, at EQUILIBRIUM, the amounts/quantities/concentrations of the "reactants" are NEVER EQUAL to the amounts/quantities/concentrations of the "products" (no matter what)!!!
Equilibrium is reached when the amounts/quantities/concentrations of the reactants and products STAY CONSTANT! These quantities must logically stay constant because the reactants and products are being used up AND formed at the same time and at the same RATE. Thus, the reaction NEVER STOPS but the amounts/quantities/concentrations of all particles remains constant at equilibrium. Since the reaction continues forever, equilibrium is DYNAMIC.
Chem 8/9- we began our new unit on Equilibrium. The initial main point to know is the STRICT DEFINITION of equilibrium. Equilibrium can ONLY and ALWAYS refer to the equal RATES of forward and reverse (CHEMICAL) reactions or (PHYSICAL) processes. It is AS IMPORTANT to know that, at EQUILIBRIUM, the amounts/quantities/concentrations of the "reactants" are NEVER EQUAL to the amounts/quantities/concentrations of the "products" (no matter what)!!!
Equilibrium is reached when the amounts/quantities/concentrations of the reactants and products STAY CONSTANT! These quantities must logically stay constant because the reactants and products are being used up AND formed at the same time and at the same RATE. Thus, the reaction NEVER STOPS but the amounts/quantities/concentrations of all particles remains constant at equilibrium. Since the reaction continues forever, equilibrium is DYNAMIC.
We then did a lab activity that is ANALOGOUS to an equilibrium process.
# posted by C @ 11:58 AM 
