Chemistry: Water and Diffusion Miss Kim Jensen Biology

Water is the most abundant compound in living things Water is important for transportation of materials such as blood and sap (which are mostly water) Water makes up % of most organisms. Water is polar – When atoms form covalent bonds, they may not share electrons equally. So one end of the molecule may be slightly positive while the other is slightly negative. Water is an excellent solvent due to the polar property of its molecules

H-bonds Hydrogen bond – is the weak attraction of opposite charges of a polar molecule. H-bonds are important in holding together larger molecules such as proteins.. This is why water drops are drops.

action.html Also, H-bonds allow capillary action in plants (water moving up thin tubes) Think of the tiniest blood vessels in your body -- your capillaries. Your blood is mostly water, and capillary action assists the pumping action of your heart to help keep blood moving in your blood vessels.

Bonds and Molecular Polarity Covalent bond Ionic bonds

Water resists temperature changes Because water can resist temperature changes, it requires more heat to increase its temperature than other substances. Also, water can lose a lot of heat when cooling. Cells exist in a watery environment so its ability to maintain certain temperatures is important.

Water expands when it freezes Water gets into cracks, freezes, expands, ect. Water also helps things move around by diffusion. Diffusion occurs from areas of higher concentration to areas of lower concentration All objects in motion have kenetic energy. When a cell is in dynamic equilibrium, stuff moves into and out of the cell at equal rates. Thus, there is no net change in concentration inside the cell.

Diffusion

True False (1) Water contracts (gets smaller) when it freezes. True False (2) Water has a high surface tension. True False True False True False True False True False True False True False True False

QuizTrue/False (1) Water contracts (gets smaller) when it freezes. (2) Water has a high surface tension. (3) Condensation is water coming out of the air. (4) More things can be dissolved in sulfuric acid than in water. (5) Rainwater is the purest form of water. (6) It takes more energy to heat water at room temperature to 212 o F than it does to change 212 o F water to steam. (7) If you filled a glass full of water from the Great Salt Lake, when it evaporated there would be 1 inch of salt left. (8) Sea water is slightly more basic (the pH value is higher) than most natural fresh water. (9) Raindrops are tear-shape(10) Water boils quicker at Denver, Co. than at the beach. (10) Water boils quicker at Denver, Co. than at the beach.

Chemistry: Life substances. Miss Jensen - Biology

All organic compounds contain carbon atoms. Carbon has four electrons available for bonding in its outer energy level. So it will share four electrons (four covalent bonds). Molecular chains are formed when molecules bond together to form macromolecules like carbohydrates. A carbohydrate is an organic compound made of carbon, hydrogen, and oxygen. Some examples are starch (potato), glycogen (liver) and cellulose. The simplest sugar is a monosaccharide that can link to form a disaccharide....polysaccharide.

Enzymes A type of protein found in all living things that increase the rate of chemical reactions. Enzymes can act on specific molecules such as carbohydrates. Each of these molecules fit into an area on the enzyme called the active site like a lock and key. The enzyme changes shape a little and puts stress on the molecule. In the case of carbohydrates, like starch, bonds are then hydrolyzed and the monosaccharide is released. After the enzyme has done its job, it releases the molecule, goes back to its original shape, then moves on to bother another molecule.

How do enzymes work in your body? The first stop along the digestive disassembly line is your mouth. As you chew your mouth and tongue move the food around preparing it for chemical digestion using enzymes. Some of the nutrients in your sandwich are starches. These are polysaccharides. The salivary glands in your mouth secrete saliva which contains a digestive enzyme called amylase. Amylase breaks down starch into smaller molecules suc as di or monosaccharides.

How do molecular chains form and break apart? Molecular chains are formed during condensation (loosing a water molecule) and are split apart during condensation ( gaining a water molecule) What are the four types of molecular chains of organic compounds (carbohydrates, lipids, proteins, and nucleic acids.)

Computer Lab assignment – today rials/chemistry/page1.htmlhttp:// rials/chemistry/page1.html Do the toutorial Do the problems #1-13. Copy and paste the questions and answers into word perfect. Put your name, period and date on the paper and turn it in.