Biomolecules

Carbohydrates Monosaccharides- Glucose, Fructose, Galactose Disaccharides - Sucrose, Lactose, Maltose Polysaccharides - Starch, Glycogen, Cellulose *insoluble in water and do not taste sweet

Hydroxyl groups make carbohydrates polar

Lipids make 18-25% of body mass few polar covalent bonds because of hydrogen oxygen ratio insoluble in polar solvents such as water- hydrophobic composed of primarily hydrogen and carbon atoms non-polar covalent bonds

Fatty Acids-simplest lipid-used to synthesize triglycerides and phospholipids -carboxly group and hydrocarbon chain-either saturated or unsaturated

Saturated fatty acid- contains single covalent bonds; each carbon atom of the hydrocarbon chain is saturated with hydrogen atoms

Unsaturated fatty acid- contains one or more double covalent bonds; not completely saturated with hydrogen atoms; has a kink or bend at site of covalent bond

*Classes of Lipids Triglycerides Phospholipids Steroids

Triglycerides Most plentiful lipid in body Made of single glycerol molecule and three fatty acid molecules Fatty acid chains make triglycerides hydrophobic

Phospholipids In third position a phosphate group links a small charged group that usually

contains nitrogen to the backbones, making this portion polar and form with hydrogen bonds with water molecules

The two fatty acids are nonpolar and can interact with other lipids Amphipathic- have both polar and nonpolar parts Make up a lot of the membrane that surrounds each cell

Steroids

Have four rings of carbon atoms Commonly encountered steroids are cholesterol, estrogen, testosterone, cortisol,

bile salts, and vitamin D= sterols because they have at least one hydroxyl group

Proteins Made up of 20 amino acids There are 9 essential that we must consume in diet that the body does not make

enough of 11 non-essential that the cells can make Responsible for the structure of body tissues Ex) Enzymes are proteins that speed up most biochemical reactions large molecules that contain carbon, hydrogen, oxygen, and nitrogen, some contain

sulfur

Amino Acids -monomer of protein each has a Hydrogen atom: amino group- R group- Carboxyl group The R group is what makes every amino acid different The covalent bond joining each pair of amino acid is a peptide bond Peptides- generally 2-50 amino acids Proteins- greater than 50 amino acids When a peptide bond occurs a molecule of water is removed make this a

dehydration synthesis reactions Breaking a peptide bond occurs during digestions of dietary proteins a hydrolysis

reaction occurs

Levels of Structural Organization in Proteins Four levels

Primary- amino acids are linked by a covalent peptide bonds to form a polypeptide chain- like a pearl necklace

Genetically determined, and changes can have serious consequences Sickle cell disease- a nonpolar amino acid (valine) replaces a polar amino acid

(glutamate) through two mutations in the oxygen-carrying protein hemoglobin. This change diminishes hemoglobin’s water solubility therefore producing crystals inside red blood cells

Secondary- protein is the repeated twisting or folding of neighboring amino acids in the polypeptide chain

Alpha helixes and beta pleated sheets Stabilized in hydrogen bonds

Tertiary structure- three dimensional shape of polypeptide chain Disulfide bridges Hydrogen bonds Ionic bonds Hydrophobic interactions Van Der Waals Forces All help determine the folding patterns

Quaternary structure- formation of proteins with more than one polypeptide chain

Fibrous proteins- insoluble in water and their polypeptide chains form long strands that are parallel to each other

Collagen- strengthens bones, ligaments, and tendons Elastin-provides stretch in skin, blood vessels, and lung tissue Keratin-hair and nail structures, waterproofs skin Dystrophine-reinforces muscle cells

Globular proteins- more or less soluble in water and their polypeptide chains are spherical in shape

Metabolic functions Enzymes which function as catalysts Antibodies, complement proteins Hemoglobin-transports oxygen Lipoproteins-transport lipids and cholesterol Membrane proteins- transport substances into and out of cells Some hormones

Enzymes Protein and non protein portion Names of enzymes usually end in ase They are highly specific- each enzyme binds to only specific substrates – which is

the reactant molecules on which the enzyme reacts They are very efficient- can catalyze reactions that are more rapid Subject to a variety of cellular controls- their rate of synthesis and their

concentration at any given time are under the control of a cells genes

Nucleic Acids- DNA and RNA Names because they were the first discovered in the nuclei of cells, contain carbon,

hydrogen, oxygen, nitrogen, and phosphorous Polymers of nucleotides DNA; deoxyribonucleic acid- forms the inherited genetic material inside each human

cell; gene- is a segment of a DNA molecule RNA-ribonucleic acid- relays instruction from the genes to guide each cells synthesis

of protein from amino acids DNA

Carbohydrate= deoxyribose- Chain of repeating monomers called nucleotides- each have three parts: Base, Sugar,

Phosphate group 1) Nitrogen base- Purines: Adenine and Guanine; Pyrimidines: Cytosine and

Thymine 2) Pentose Sugar 3) Phosphate group Double stranded Helix

Law of Complimentary Base- A-T (A-U), C-G A with T, G with C

RNA- Sugar-Ribose Bases: Purines: Adenine and Guanine; Pyrimidines: Cytosine and Uracil Single stranded Messenger RNA, Ribosomal RNA, and Transfer RNA Rule: A with U, and G with C

Adenosine Triphosphate ATP Is the energy currency of living systems Transfers energy liberated in exergonic catabolic reactions to power cellular

activities that require energy Muscular contractions, movement of chromosomes during cell division, transport

substances around cell membranes, synthesis of larger molecule from smaller ones