Made of nucleotides nitrogen base pentose sugar phosphate

• Made of nucleotides (nitrogen base, pentose sugar, phosphate) • Informational • C, H, O, N, P • Phosphodiester linkage

• Deoxyribose • Double stranded • Thymine • Makes up genes • Ribose • Single stranded • Uracil • Structure and protein synthesis

link

ATP serves as a common energy source for organisms because A. It is the smallest energy molecule. B. it is extremely stable and can be stored in the cell for long periods of time. C. its energy can be easily transferred to do cellular work. D. traces of it have been found in fossils of ancient organisms dating back to the beginning of life on Earth. Answer: C

l a r t n e C a m g o D

Peptide bond • C, H, O, N, sometimes S • Molecular tools • Structure, enzymes, antibodies Transport, movement, receptors, hormones • Chains of amino acids linked by peptide bonds

• Gives protein its properties

Secondary Primary Tertiary Quaternary link

Sickle-cell anemia results from a point mutation in the HBB gene. The mutation results in the replacement of an amino acid that has a hydrophilic R-group with an amino acid that has a hydrophobic Rgroup on the exterior of the hemoglobin protein. Such a mutation would most likely result in altered A. Properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules. B. DNA structure as a result of abnormal hydrogen bonding between nitrogenous bases. C. Fatty acid structure as a result of changes in ionic interactions between adjacent fatty acid chains. D. Protein secondary structure as a result of abnormal hydrophobic interactions between Rgroups in the backbone of the protein. Answer: A

Heat p. H changes High salts

2001 - Proteins- large complex molecules- are major building blocks of all living organisms. Discuss the following in relation to proteins. a. The chemical composition and levels of structure of proteins. 2008 -

Substrate bound to active site by weak interactions (hydrogen bond, ionic bond, Van der Waals force, etc. )

The enzyme cystathionine b-synthase (CBS) catalyzes the condenation of serine and homocysteine to produce cystathionine, an important intermediate in the biosynthesis of cysteine. Deficiency of CBS activity results in toxic levels of homocysteine and is the most common cause of homocystinuria, a disease whose symptoms include dislocated eye lenses, skeletal and vascular problems, and mental retardation. Mammalian CBS is a unique heme protein that requires the cofactor pyridoxal 5'-phosphate (PLP). Although heme is essential for activity inmammalian CBS, the chemistry is performed by PLP, and heme is not present in the enzyme of lower organisms. Why, then, has nature included a heme in the CBS of mammals? Our hypothesis is that the heme of CBS is acting as a regulator of enzyme activity. A number of studies demonstrate that there is communication between the heme and the active site, e. g. small molecule binding and reduction of the heme both diminish enzyme activity. In collaboration with Professor Jan Kraus (University of Colorado, Denver), we are currently probing the enzyme and the heme with a variety of spectroscopic and biochemical methods, such as electronic absorption and magnetic circular dichroism (MCD), and resonance Raman spectroscopies, site-directed mutagenesis, and radiochemical enzyme assays in an attempt to unlock the mystery of the heme in this enzyme.

All of the following are true about enzymes EXCEPT: a. Enzymes accelerate reactions by lowering the energy of activation. b. Some enzymes are allosteric. c. All enzymes in the human are most active at 37 C and at a p. H around 7. d. They catalyze reactions in both directions.