Augustine Mai, Isaac MandefroPeriod 8

Unit 3 Notes

Organic chemistry is the chemistry of carbon compounds.

Majority of organic molecules found in living organisms can beclassified into one of four types:- carbohydrates - proteins- lipids -nucleic acids

Four most common elements found in living things:-Hydrogen -Carbon-Nitrogen -Oxygen

Roles:sulfur -in some amino acidscalcium -cofactor in some enzymesphosphorous - phosphate groups in ATPiron- in cytochromessodium- in membrane function

Structure of water

Water is the solvent of life Almost all cells have water within and in surrounding environment. Hydrogen and oxygen atoms in a water molecule are held together by a polar covalent

bond Polar covalent bonding results from unequal sharing of electrons Each oxygen–hydrogen bond is a polar covalent bond. Results in a slight negative charge

at the oxygen end of the molecule and a slight positive charge at the end with the two hydrogen molecules

Two ends of each water molecule have opposite charges so H2O molecules interact with each other in different ways.

Augustine Mai, Isaac MandefroPeriod 8

Properties of water and living organisms

Thermal Properties High Specific heat: water can absorb/ give off a lot of heat without changing the

temperature too much Water is a coolant for the body Has high heat of vaporization; water absorbs a great deal of heat when it evaporates Internal body heat turns to perspiration, with evaporates from skin. Heat used to turn

liquid into evaporation so perspiration is a cooling method by lowering temperature.

Cohesive Properties H2O molecule- highly cohesive Cohesion: molecules of the same type are attracted to each other Attraction due to polar covalent bonding

Solvent properties

Excellent solvent of other polar molecules Most molecules found in/out of the cell are also polar (Includes Carbohydrates,

Proteins, Nucleic Acids) Most lipids are non-polar Water is a medium in which biochemistry of a cell occurs

Carbohydrates, Lipids and Proteins

Living things composed of a variety of molecules

Molecule; (Sub-components)-Carbohydrates; (Monosaccharides); Sub-categories (Monosaccharides, disaccharides, polysaccharides)-Lipids; (Glycerol and fatty acids)

Augustine Mai, Isaac MandefroPeriod 8

-Proteins(Polypeptide); (Amino Acids)-Nucleic Acids; (Nucleotides)

All organic molecules contain carbon Not all carbon containing molecules are organic

Functions of carbohydrates in plants and animals

Carbohydrates among most found biochem molecules in plants/animals Carbohydrates have different sizes (monosaccharide, disaccharide, etc.) Animals

Glucose-chemical fuel for cell respiration (mono.)Lactose-Makes up some solutes in milk (di.)Glycogen-stores glucose in liver and muscles (poly.)

PlantsFructose- found in many fruits; makes sweet(Mono.)Sucrose- often transported from leaves of plants to other locations in plants by vascular tissue (Di.)Cellulose- one of primary components in plant cell walls (Poly.)

Role of Lipids

Triglyceride lipids, solid then called fat, liquid then called oil Excess fat is stored in adipose cells Efficient for storing energy Stores twice as much chemical energy as carbohydrates Important for thermal insulation Special lipid- phospholipid makes up the double layer of all cell membranes

Condensation and Hydrolysis Reactions

Augustine Mai, Isaac MandefroPeriod 8

Foods are chemically digested. The digestive enzymes that accomplish this are hydrolysingenzymes.

Each reaction is called a hydrolysis and requires a molecule of water asa reactant.

Water is always split in hydrolysis Ex.

-hydrolysis of a disaccharide to two monosaccharides lactose + water → glucose + galactose-hydrolysis of a polysaccharide to many monosaccharides;starch + (many) water → (many) glucose

Condensation reactions are the opposite of hydrolysis reactions In condensation reactions, the water molecules are products rather than reactants

DNA Structure

Nucleotides are building blocks of DNA Each nucleotide of DNA is composed of a phosphate, deoxyribose sugar, and base 4 possible nitrogenous bases: adenine, thymine, guanine, cytosine DNA has double helix shape Base pairs are adenine, thymine and guanine, cytosine Adenine and thymine are held together by two hydrogen bonds. Cytosine and guanine

are held together by three hydrogen bonds.

Augustine Mai, Isaac MandefroPeriod 8

DNA replication

DNA replication: Cells prepare for a cell division by doubling the DNA content of the cell Double quantity of DNA + one exact copy of each molecule Early event of DNA replication is separation of double helix into 2 strands Enzyme helicase causes separation of strands In nucleoplasm, there are many free floating nucleotides. Nucleotides available to form

complementary pairs Formation of a covalent bond between two adjoining nucleotides is catalysed by one of

the DNA polymerase enzymes that's important in the process.

Significance of Complementary base pairings

Pattern of DNA replication ensures 2 identical copies of DNA Every DNA molecule after replication has a strand that was old, now paired with a

strand that is new

Augustine Mai, Isaac MandefroPeriod 8