Organic compounds Lipids, Carbohydrates, Proteins, and Nucleic Acids

Essential for life

•  Organic compounds: •  Contain carbon

•  Most are covalently bonded

•  Example: •  C6H12O6 (Glucose)

•  Inorganic Compounds: •  Lack carbon

•  Tend to be simpler compounds

•  Example: •  H2O (Water)

Why is carbon special?

•  Carbon has special bonding properties due to its ability to make 4 covalent bonds with itself and other elements

•  Can form single, double, and triple bonds

•  Can form chain and/or ring structures

•  This leads to a huge diversity in organic molecules •  Over 4 million organic compounds exist

c Carbon

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Carbon bonds

Large organic molecules

•  Monomers: •  Small, single units, or molecules that can bond together

•  Polymer: •  Many monomers bonded together

•  Forms a macromolecule

Inorganic - water

•  Most abundant INORGANIC compound

•  Vital properties: •  High heat capacity

•  Polarity / solvent properties

•  Chemical reactivity

•  Cushioning

Inorganic - Salts

•  Easily splits (dissociate) into ions in the presence of water

•  Vital to many body functions

•  Includes electrolytes •  Conduct electrical currents

Acids & bases

•  Acids: •  Can release detectable

hydrogen ions

•  Bases: •  Proton acceptors

•  Neutralization reaction: •  Acids and bases react to

form water and a salt

Ph scale

•  Measures relative concentrations of hydrogen ions

•  pH 7 = neutral

•  pH below 7 = acid

•  pH above 7 = base

•  Buffers: •  Chemicals that can regulate

pH change

Organic compounds

•  Energy stored in organic molecules determines its caloric value

•  Proteins, carbs, and fates are 3 organic compounds with different structures and different caloric values based on their structures

Discussion!

•  Which foods contain carbohydrates?

•  Distinguish between “good” carbs (healthy) and “bad” carbs (unhealthy)

•  Answer: •  Good: fruits, veggies, whole grains (rice, bread pasta)

•  Bad: soda, sugary cereals, candy, cookies, crackers

carbohydrates

•  Composed of: Carbon, Hydrogen, and Oxygen in ring shapes

•  Function of a carb is to provide energy and structure for cells

•  Includes sugars and starches

•  Classified according to size: •  Monosaccharide – simple sugar •  Disaccharide – two simple sugars joined together •  Polysaccharide – long branching chains of linked simple

sugars

carbohydrate

Carbohydrates

•  Main sources of energy for the cell

•  If not used for energy, they are stored in the cells

•  Digestion breaks bond between large carbohydrates so simple sugars can be absorbed into the blood stream through the walls of the intestines •  Bloodstream carries simple sugars throughout body

•  Simple sugars used as fuel, releasing energy, stored as ATP

•  Caloric value: 4 calories per gram

Lipids

•  Contain carbon, hydrogen, and oxygen •  Have more Carbon-Hydrogen bonds than carbs •  This means more energy!

•  Carbon and hydrogen outnumber oxygen

•  Insoluble in water •  i.e. doesn’t dissolve

•  Main function: energy storage

•  Monomers of lipids: •  Glycerols •  Fatty Acids

lipids

•  Important for energy when carbs are scarce

•  Functions: •  Long term energy storage

•  Cushioning of vital organs

•  Insulation for the body

•  Major component of cell membranes

•  Necessary for vitamin and hormone production

•  Caloric Value: 9 calories per gram

lipids

lipids

Fats

•  Saturated Fats: •  Solid at room temperature

•  Derived mostly from animals

•  Raise levels of “Bad” Cholesterol (LDL)

•  Can clog arteries

•  Examples:

•  Butter, Lard, Cheese

•  Unsaturated Fats: •  Liquid at room temp

•  Derived mostly from plants

•  Raise level of “Good” Cholesterol (HDL)

•  Examples:

•  Olive oil, Avocado, Nuts

Proteins

•  Made of amino acids

•  Contain carbon, oxygen, hydrogen, nitrogen, and sulfur (sometimes!)

•  Account for over HALF of the body’s organic matter •  Provides for construction materials for body tissues

•  Plays vital role in cell function

•  Act as enzymes, hormones, and antibodies

Types & Functions of Proteins

1.  Structural: •  Provide support and strength •  Examples:

•  Keratin in hair, fur, horns, and claws

2.  Binding: •  Attach to and transport substances throughout the body •  Example:

•  Hemoglobin binds oxygen in blood

3.  Defense: •  Helps the immune system defend against foreign substances

in the body •  Examples:

•  Antibodies on the surface of WBCs

Types & Functions of Proteins

4.  Movement: •  Responsible for muscle contraction •  Example:

•  Actin & myosin fibers in muscle

5.  Signaling: •  Maintains communication between cells •  Example:

•  Hormones (insulin, endorphins) and Neurotransmitters

6.  Chemical Reactions: •  Enzymes are proteins that act as catalysts for reactions •  Example:

•  Digestive enzymes like lipase

Nucleic Acids

•  Make up genes •  The blueprint for life (we will get to genes in a few units!)

•  Direct growth and development

•  Dictate protein structure

•  Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus

•  Largest biological molecules in the body

Nucleotide Structure

•  Building blocks: Nucleotides •  Consists of 3 parts:

1.  Sugar (either ribose or deoxyribose)

2.  Phosphate

3.  Nitrogen base

•  5 bases are A, T, G, C, and U

•  DNA and RNA