Sam Lehrman
Natalie- Black

The Chemistry of Life

3.1 Chemical Elements and Water
3.1.5 -- Thermal, Cohesive, and Solvent Properties of Water

Water moderates air temperature by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler. Water is effective at holding heat because it can absorb or release a relatively large amount of heat with only a slight change in its own temperature. The ability of water to stabilize temperature stems from its relatively high specific heat .

Water molecules stay close to each other as a result of hydrogen bonding. When water is in its liquid form, its hydrogen bonds are very weak and form, break, and re-form frequently. Each hydrogen bond only lasts a few trillionths of a second, but the molecules are constantly forming new bonds with partners around them. At any instant, most of the water molecules are bonded to their neighbors, making water more structured than most other fluids. The fleeting hydrogen bonds hols the liquid together, which is known as cohesion .

An aqueous solution is one in which water is the solvent. Water is a very versatile solvent (not a universal solvent because is can not dissolve everything Ex: cells, skin, etc.) because of the polarity of the water molecule.

3.1.6 -- Coolant, Medium for Metabolic Reactions, and Transport Medium

As a liquid evaporates, the surface of the liquid left behind cools down. This evaporative cooling occurs because the "hottest" molecules, those with the most kinetic enegry are the most likey to leave gas. For example, with sweat, we perspire, it evaporates, and cools us down.

Cohesion due to hydrogen bonding contributes to the transport of water and dissolved nutrients against gravity in plants. Adhesion , the clinging of one substance to another, also plays a role. Adhesion of water to the walls of cells helps counter the downward pull of gravity.

3.2 Carbohydrates, Lipids, and Proteins

3.2.1 -- Organic and Inorganic Compounds
Compounds containing carbon are organic compounds . Organic compounds range from simple molecules, such as methane (CH 4 ), to large ones, such as lipids. Most organic compounds contain hydrogen atoms in addition to carbon atoms. Carbohydrates, lipids and proteins are organic. Inorganic compounds are those that do not contain a carbon such as ammonia (NH 3 ). Minerals are inorganic.

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Amino Acid Structure:
external image aminoacidstruc.jpg

Glucose Molecule:
Ribose Molecule:

external image RiboseCompound.gif
Fatty Acid Structure:

external image fat_f2.jpg

Carbon, Hydrogen, Oxygen, and Nitrogen are the most frequently occurring elements in organisms and are the basic building blocks for all life on Earth. That's why all organisms are call carbon-based life forms.

Although carbon, hydrogen, oxygen, and nitrogen are the basic building blocks for all living things other elements are essential for life. These elements such as sulfur, calcium, phosphorous, iron, and sodium and necessary to carry out many life processes but are needed in only small amounts. These elements and know as trace elements.

Sulfur- Helps protect all cells of the body from air polution and radiation.
Calcium- Helps in the formation and strengthening of teeth and bones.
Phosphorous- Strengthens our teeth and bones, helps in the breakdown of many foods, and helps in the maintaining of a healthy blood sugar level.
Iron- Oxidizes the blood and helps with the formation of hemoglobin in the red blood cells.
Sodium- Helps with the absorption of nutrients into our blood stream.

Diagram of Water molecule, demonstrating its polarity and hydrogen bond formation.


3.2.3-- List three examples each of monosaccharides, disaccharides and polysaccharides.

- Monosaccharides are the simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides.Three examples of monosaccharides include glucose (which is the most common), fructose, and galactose. Disaccharides are double sugars consisting of two monosaccharides joined by dehydration synthesis. Three examples of disaccharides include maltose, lactose, and sucrose. Polysaccharides are polymers of up to over a thousand monosaccharides, formed by dehydration syntheses. Three examples of polysaccharides include starch, glycogen, and cellulose.

3.2.4-- State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose, and cellulose in plants.

-Glucose is a major nutrient which is essential for cellular respiration in animals. This is a process where cells extract the energy stored in glucose molecules. Lactose is a sugar found in milk. Glycogen is the most storaged form of carbohydrates in animals. Animals use their excess glycogen when not intaking a sufficient amount of carbs. Plants generally transport carbohydrates from leaves to roots and other nonphotosynthetic organs in forms of sucrose. Cellulose is a major component of the tough walls which enclose their plants cells.

3.2.6-- State three functions of lipids.

3.2.7-- Compare the use of carbohydrates and lipids in energy storage.