Molecules are the smallest particles into which a non-elemental substance can be divided while maintaining the physical properties of the substance (water). Each type of molecule corresponds to a specific chemical compound. Molecules are a composite of two or more atoms. An electrically neutral group of two or more atoms (covalent bonds). Covalent bonding is a common type of bonding, in which the electronegativity difference between the bonded atoms is small or nonexistent (water is polar covalent, so O end has partial neg. charge and H ends have partial pos. charge).
24 Atoms to make up human body.
95% = Oxygen, Carbon, Hydrogen, Nitrogen
(Actually, if you add in calcium and phosphorus, you have 99% of the body.)
About .85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. The other .15% are trace elements.
Properties of Water
Charge – results in properties of cohesion (sticks to itself) and adhesion (sticks to other things) due to hydrogen bonds (polar covalent).
Cohesion results in surface tension, and this, in turn, results in capillary action (seen in plants, for example).
How is this important in the human body? (Osmosis)
Hydrogen bonds also result in ice floating, since water forms crystalline structures at 32 degrees and this form is lighter than liquid water. The properties of ice are still not completely understood.
High Specific Heat – Water is held together by hydrogen bonds. Because the molecules are being held tightly in place by these bonds, the H2O molecules don't move much when heated. It takes more and more heat to move the molecules, causing water to have a high specific heat capacity. This concept is important on a world-wide scale. The oceans and lakes help regulate the temperature ranges that billions of people experience in their towns and cities. Water surrounding or near cities take longer to heat up and longer to cool down than do land masses, so cities near the oceans will tend to have less change and less extreme temperatures than inland cities. This property of water is one reason why states on the coast and in the center of the United States can differ so much in temperature patterns.
Water's specific heat capacity is 4.184 joules per gram, meaning that it takes 4.184 joules to raise the temperature of 1 gram of water by 1 degree Celsius. If this number sounds familiar, it's because a common unit called the calorie is based on the heat capacity of water; 1 calorie is equal to 4.184 joules.
How is this important in the human body? (Helps us maintain homeostasis.)
High Heat of Vaporization - Heat of vaporization is the amount of energy needed to vaporize a given amount of mass of a substance; water's heat of vaporization is 2,257 joules per gram, or 539.4 calories.When boiling water on the stovetop, the metal pan used to boil the water can become scalding hot while the water inside remains lukewarm. This is because the pan has a much lower specific heat than water, meaning it changes temperature much more quicklyWhen boiling water on the stovetop, the metal pan used to boil the water can become scalding hot while the water inside remains lukewarm. This is because the pan has a much lower specific heat than water, meaning it changes temperature much more quicklyWhen boiling water on the stovetop, the metal pan used to boil the water can become scalding hot while the water inside remains lukewarm. This is because the pan has a much lower specific heat than water, meaning it changes temperature much more quickly.When boiling water on the stovetop, the metal pan used to boil the water can become scalding hot while the water inside remains lukewarm. This is because the pan has a much lower specific heat than water, meaning it changes temperature much more quickly.
When boiling water on the stove, the pan may be scalding hot while the water is still lukewarm. This is because it has a lower specific heat than water, so it changes temperature more quickly.
·The high heat of vaporization of water is important for the earth's climatens can absorb a great amount of heat generated from the sun. Also, when evaporation from the tropical waters occurs, it moves to the earth's poles, and heat is released as it condenses and rain is formed.
Evaporative cooling is important on many levels (stabilizes temps of lakes and ponds; prevents plants from becoming too hot, etc.). How is it important to humans?
Sweat evaporation from humans helps them dissipate heat and prevent overheating (but too much of a good thing could make us unstable)….
The above two properties can vary some with temperature (but very slightly) and pressure (so altitude can cause changes)….
Solubility – dissolves ionic molecules. Universal Solvent. (Hydrophobic substances will not dissolve in water: oils, for instance.)
Water can pretty easily dissolve ions (electrically charged atomic molecules, such as NaCl) and polar molecules (Glucose, for example, the body’s main source of energy).
How is this important to humans? (Most trace elements, etc. are easily absorbed into the body and transferred around the body via H20 in blood and other bodily fluids).
The ability of water to dissolve ionic molecules is vitally important to life as salts are very important in the body. For instance, Sodium helps with absorption of Glucose; it allows some molecules to pass the cell membrane that could not otherwise pass (facilitated diffusion); and it helps with transport of molecules and communication between cells because it helps establish a negative charge on the cell membrane relative to the fluid outside the cell. It’s essential to the sending of nerve signals, muscle contractions, fluid balance in the body, etc.
Diffusion - Diffusion is the tendency of molecules to spread into an available space. This tendency is a result of the intrinsic thermal energy (heat) found in all molecules at temperatures above absolute zero. Without other outside forces at work, substances will move/diffuse from a more concentrated environment to a less concentrated environment. No work is performed for this to happen, as diffusion is a spontaneous process.
DO DIFFUSION EXPERIMENTS USING BALLOONS WITH FLAVORING INSIDE AND HOT/COLD WATER WITH FOOD COLORING.
Passive transport is the diffusion of substances across a membrane. This is a spontaneous process and cellular energy is not expended. Molecules will move from where the substance is more concentrated to where it is less concentrated. (The membrane must be permeable or at least semi-permeable, of course, as most are….) Give facilitated diffusion diagram.
Osmosis is the spontaneous net movement of solvent molecules through a partially permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves, without input of energy, across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations.
Osmosis is essential in biological systems. In general, cell membranes are impermeable to large and polar molecules, such as ions, proteins, etc. while being permeable to non-polar and/or hydrophobic molecules like lipids, as well as to small molecules like oxygen, carbon dioxide, nitrogen, nitric oxide, etc. Permeability depends on solubility, charge, or chemistry, as well as solute size. Water molecules travel through the plasma membrane or tonoplast membrane (the membrane surrounding a vacuole) by diffusing across the phospholipid bilayer via aquaporins (small trans membrane proteins similar to those in facilitated diffusion channels). Osmosis provides the primary means by which water is transported into and out of cells.
Give diagram regarding Osmosis in hypertonic, isotonic, and hypotonic solutions.
DO OSMOSIS EXPERIMENT WITH POTATO PIECES.
GIVE OSMOSIS WORKSHEET and CELLULAR TRANSPORT AND THE CELL CYCLE.
Carbon based life forms
Living things are carbon based. Carbon forms the key component for all known naturally occurring life on Earth. Complex molecules are made up of carbon bonded with other elements, especially oxygen, hydrogen and nitrogen, and carbon is able to bond with all of these because of its four valence electrons. Carbon is abundant on earth. It is also light weight and the atom is relatively small in size, making it easier for enzymes to manipulate carbon molecules.
Nucleic Acids – DNA and RNA; initially named because found in nucleus, but also in prokaryotes; DNA is largest molecule; C, O, H, N.
This is where we ended after week 1.... In addition to the couple of worksheets I gave them to take home, they are going to work on a project regarding organization of systems. Here is that assignment:
We talked today about levels of organization in the Universe: within the atomic world, within galaxies, within biomes, within our bodies. The assignment is to draw, label and color an example of each of the following items on a single sheet of paper. I told them that they could elect to find pictures online to create a small poster, or instead use Lego's to create examples of the different items, use clay to create examples, or pipe cleaners, etc., etc.
(the above are the most important to what we are doing this year)
The original list also included:
(They don't have to do these, but can if they want)
Nucleus – the “brain” of the cell. Contains most of the cell’s genetic material: DNA, which combines with proteins to form chromosomes. Contained on each chromosome are many genes, which are molecular units of heredity. All organisms have many genes corresponding to various biological traits, some of which are immediately visible, such as eye color or number of limbs, and some of which are not, such as blood type, increased risk for specific diseases, or the thousands of basic biochemical processes that comprise life.
DNA forms a double stranded helix (generally). The two strands are attached by weak hydrogen bonds. A=T; C=G; T=A; G=C
Two types of proteins in the cell include: Channel Proteins and Carrier Proteins. A channel protein forms a pore that spans the lipid bilayer of the cell membrane and allows certain solutes to traverse the membrane. Carrier proteins, like transporins, also transfer molecules across the membrane (see diagram of facilitated diffusion).
DO LIVER ENZYME EXPERIMENT.
Pro/Metaphase – nuclear envelope disintegrates; poles develop; microtubules overlap.
Osteoblasts – responsible for bone formation; do not divide. Created by Osteogenic cells.
Tissues – 4 main types in the body
Nervous – found in the brain, spinal cord, and peripheral nerves. Composed of neurons and glia.