Friday, October 19, 2007
Fri-Day 2
Bio- we discussed and came up with examples of the "Levels of Organization" that complex, multi-cellular organisms need to survive. Without cell differentiation and levels of organization, humans could just be slabs of skin cells, the equivalent of a tissue culture, incapable of walking, talking, or thinking.
The simplest level of organization contains cells, then related cells work together to form tissues, which work together to form organs, which work together to form organ systems which make up the entire complex organism!
Speaking of working together, in single-celled organisms and in EACH cell of a multi-cellular organism, ORGANELLES must work together to keep the cell alive.
This weekend, think of ways that various organelles work together, that is, the life process of one organelle (e.g. mitochondria=respiration=provides cell energy via ATP) helps another organelle to perform its life process (cell membrane=excretion via active transport requires ATP from the mitochondria!!).
We looked at some cool videos involving active transport: the paramecium uses its contractile vacuole to pump water from its inside (lower water concentration) to the outside freshwater (higher water concentration) which requires ATP (for the contraction of the vacuole).
Look at your notes and previous blog entries (here) for the answers to each of the unit objective questions.
Good luck on the test on Monday!
Chem 7/8- we reviewed the factors that influence the rate of a chemical reaction (number of effective collisions per second) including the fundamental factor for each specific reaction: the nature (strength of the bonds) of the reactants. The stronger the bonds within the reactant particles, the slower the reaction at room temperature because so much energy is required to break the bonds (i.e. HIGH activation energy) that there are very few effective collisions per second at room temperature.
We then discussed the two factors that determine whether a given reaction is SPONTANEOUS (occurs without a constant supply of energy from a battery or electrical outlet or separate burner). The two factors are
1. the potential energy of the products relative to that of the reactants (nature favors LOWER PE, MORE STABILITY, STRONGER BONDS) and
2. the ENTROPY (chaos, disorder, randomness, number of ways that the particles can be arranged) of the products relative to that of the reactants. Nature favors HIGHER entropy, more chaos and disorder! Statistically and by definition, it is just more PROBABLE and natural for things to be arranged in MORE WAYS than fewer ways.
Chem 9- we reviewed the factors that influence the rate of a chemical reaction (number of effective collisions per second). We focused on the surface area of solids (and liquid or aqueous solutions too) showing that DECREASING particle size/INCREASING surface area EXPOSES more particles for collision with the other reactants thus increasing the number of collisions per second.
The fundamental factor that determines the basic rate for each specific reaction at "normal" or room temperature is: the "nature" (strength of the bonds) of the reactants. This factor cannot be "added" or taken away from a given reaction. The stronger the bonds within the reactant particles, the slower the reaction at room temperature because so much energy is required to break the bonds (i.e. HIGH activation energy) that there are very few effective collisions per second at room temperature.
The simplest level of organization contains cells, then related cells work together to form tissues, which work together to form organs, which work together to form organ systems which make up the entire complex organism!
Speaking of working together, in single-celled organisms and in EACH cell of a multi-cellular organism, ORGANELLES must work together to keep the cell alive.
This weekend, think of ways that various organelles work together, that is, the life process of one organelle (e.g. mitochondria=respiration=provides cell energy via ATP) helps another organelle to perform its life process (cell membrane=excretion via active transport requires ATP from the mitochondria!!).
We looked at some cool videos involving active transport: the paramecium uses its contractile vacuole to pump water from its inside (lower water concentration) to the outside freshwater (higher water concentration) which requires ATP (for the contraction of the vacuole).
Look at your notes and previous blog entries (here) for the answers to each of the unit objective questions.
Good luck on the test on Monday!
Chem 7/8- we reviewed the factors that influence the rate of a chemical reaction (number of effective collisions per second) including the fundamental factor for each specific reaction: the nature (strength of the bonds) of the reactants. The stronger the bonds within the reactant particles, the slower the reaction at room temperature because so much energy is required to break the bonds (i.e. HIGH activation energy) that there are very few effective collisions per second at room temperature.
We then discussed the two factors that determine whether a given reaction is SPONTANEOUS (occurs without a constant supply of energy from a battery or electrical outlet or separate burner). The two factors are
1. the potential energy of the products relative to that of the reactants (nature favors LOWER PE, MORE STABILITY, STRONGER BONDS) and
2. the ENTROPY (chaos, disorder, randomness, number of ways that the particles can be arranged) of the products relative to that of the reactants. Nature favors HIGHER entropy, more chaos and disorder! Statistically and by definition, it is just more PROBABLE and natural for things to be arranged in MORE WAYS than fewer ways.
Chem 9- we reviewed the factors that influence the rate of a chemical reaction (number of effective collisions per second). We focused on the surface area of solids (and liquid or aqueous solutions too) showing that DECREASING particle size/INCREASING surface area EXPOSES more particles for collision with the other reactants thus increasing the number of collisions per second.
The fundamental factor that determines the basic rate for each specific reaction at "normal" or room temperature is: the "nature" (strength of the bonds) of the reactants. This factor cannot be "added" or taken away from a given reaction. The stronger the bonds within the reactant particles, the slower the reaction at room temperature because so much energy is required to break the bonds (i.e. HIGH activation energy) that there are very few effective collisions per second at room temperature.
# posted by C @ 11:38 AM 
