Chemical level of organization

Most common elements in the body:

Major elements: (96%) Hydrogen Oxygen Nitrogen Carbon

Lesser elements (3%) Phosphorus Calcium Sulfur Sodium Chlorine Magnesium Iron Potassium

The role of chemistry in the body

Cells need energy Get energy from food: carbs, protein, fats Bring raw material into cells

Metabolism: inside the cells

Anabolism: building; requires energy; ex: building protein from a.a

Catabolism: breakdown; releases energy to be converted to ATP

Organic compounds

Types: carbs, lipids, proteins, nucleic acids, Contain carbon Large Contain carbon skeleton + functional groups

1. Carbohydrates

Composed of carbon, hydrogen, and oxygen. Carbohydrates store energy. Classified by size

Types of carbs

Monosaccharides: smaller immediate energy source glucose fructose

Disaccharides: 2 monosaccharides Broken down before absorbed sucrose (table sugar) (glucose + fructose) lactose

Types of carbohydrates (cont.) Polysaccharides:

very long sugars not sweet EX:

Glycogen: in humans, stored excess sugar in liver & skeletal muscles

starches: found in plants (potatoes, rice, corn) Cellulose: found in plants, “fiber”, protect plant cells

humans can not digest

2. lipids

20% of healthy adult Hydrophobic:–repel water Long-term energy storage. Too much can be harmful.

Types of lipids

a. triglycerides: 3 carbon backbone with three fatty acids attached

more energy than carbs and proteins Stored as adipose tissue

Types of triglycerides

saturated: solid at room temperature, “saturated” with hydrogen atoms.

Monounsaturated: contain less than the maximum number of hydrogen atoms in one or more of its fatty acid chains, avocados, nuts, olive oil, peanut oil

Polyunsaturated: even fewer hydrogen atoms, corn oil, sunflower oil, fish.

b. phospholipids

cell membranes

c. Steroids Hydrophobic, rings of carbon Ex: sex hormones: estrogen and

testosterone, vitamin D, cholesterol: found in membranes that surround cells (necessary, but too much is bad)

d. others

ex: vitamin E,K, and beta-carotenes

3. Proteins

composed of amino acids Contain C, H, O, N, & sometimes S. “folded” shape determines function Organisms use only 20 aa to make proteins-

Different combinations produce different proteins. Ex: hormones, antibodies, enzymes speed

up some reactions. Denature: unravel and lose shape

pH, salt, temp.

Protein catabolism

Breakdown releases nitrogen: recycled or converted to urea (by the liver) to be urinated.

If liver failure: inc. blood ammonia (NH3) levels (ammonia is toxic to brain cells)

4. Nucleic acids

Contain C, H, O, N, & P. contain hereditary or genetic information. Code for proteins Substructures called nucleotides. 2 types: DNA & RNA.