Amino acids contain which two functional groups? a. and b. and c. and d. and Answer: c

ATP serves as a common energy source for organisms because (a) it is the smallest energy molecule. (b) it stores the least energy of any energy source. (c) its energy can be easily transferred to do cellular work. (d) it is extremely stable and can be stored in the cell for long periods of time. (e) traces of it have been found in fossils of ancient organisms dating back to the beginning of life on Earth. Answer: c

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. Most are proteins. d. All enzymes in the human are most active at 37 C and at a pH around 7. e. They catalyze reactions in both directions. Answer: D

The bonding of two amino acid molecules to form a larger molecule requires a. the release of a water molecule. b. the release of a carbon dioxide molecule. c. the addition of a nitrogen atom. d. the addition of a water molecule. e. an increase in activation energy. Answer: a

A particular poison binds to certain enzymes at positions other than the active site,thus deactivating the enzyme. This is an example of a. noncompetitive inhibition b. competitive inhibition c. denaturing d. allosteric inhibition e. irreversible inhibition Answer: D

Certain metabolic pathways are affected by the Buildup of a product which interacts with an enzyme Catalyzing one of the initial steps of the pathway; This can be an example of (a) transcriptional regulation. (b) thermodynamic regulation. (c) translational regulation (d) feedback inhibition. (e) posttranscriptional modification. Answer: d

Which of the following statements regarding coenzymes is true. (a) They are essential for metabolic reactions in animals but not in plants. (b) They can facilitate metabolic reactions by combining with enzymes and their active sites. (c) They are minerals that alter the pH of cells and thus increase the probability of chemical reactions. (d) They are synthesized in the rough ER of eukaryotic cells. (e) They typically work best at temperatures below 37C. Answer: b

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

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

Gives protein its properties

Primary Secondary Tertiary Quaternary

Heat pH 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

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.Professor Jan Kraus

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. Most are proteins. d. All enzymes in the human are most active at 37 C and at a pH around 7. e. They catalyze reactions in both directions. Answer: D

Certain metabolic pathways are affected by the Buildup of a product which interacts with an enzyme Catalyzing one of the initial steps of the pathway; This can be an example of (a) transcriptional regulation. (b) thermodynamic regulation. (c) translational regulation (d) feedback inhibition. (e) posttranscriptional modification. Answer: d

Amino acids contain which two functional groups? a. and b. and c. and d. and Answer: c

Which of the following statements regarding coenzymes is true. (a) They are essential for metabolic reactions in animals but not in plants. (b) They can facilitate metabolic reactions by combining with enzymes and their active sites. (c) They are minerals that alter the pH of cells and thus increase the probability of chemical reactions. (d) They are synthesized in the rough ER of eukaryotic cells. (e) They typically work best at temperatures below 37C. Answer: b

ATP serves as a common energy source for organisms because (a) it is the smallest energy molecule. (b) it stores the least energy of any energy source. (c) its energy can be easily transferred to do cellular work. (d) it is extremely stable and can be stored in the cell for long periods of time. (e) traces of it have been found in fossils of ancient organisms dating back to the beginning of life on Earth. Answer: c

The bonding of two amino acid molecules to form a larger molecule requires a. the release of a water molecule. b. the release of a carbon dioxide molecule. c. the addition of a nitrogen atom. d. the addition of a water molecule. e. an increase in activation energy. Answer: a