Exam 2 – Chemistry Answers – Flashcards

• Uracil
• pyrimidine
• nucleoside name uridine 

• thymine
• pyrimidine
• nucleoside name thymidine 

• cytosine
• pyrimidine
• nucleoside name  cytodine

• Adenine
• purine
• nucleoside name adenosine

• guanine
• purine
• nucleoside name guanosine

the helix

the pleated sheet

hydrogen bonds

ionic attractions

hydrophobic interactions

disulfide bridges

• a denatured protein has a different tertiary structure than its native state
• egg white meringue contains denatured proteins
• soakin fish in lime juice to make ceviche denatures the proteins 
• digestive enzymes hydrolyze proteins

• an enzyme yields a specific product, whereas a nonbiological catalyst may produce more than one product, and side reactions may occur
• a sustrate must bind to the active site before a reaction occurs
• an enzyme is specific for a substrate
• reactions occure at the active site, which usually consists of a crevice on the surface of the enzyme

• enzyme atcive site has a rigid structure complementary to that of the substrate 

the carboxylate anion picks up a proton (COO- becomes COOH)

• unbranched polymers composed of repeating monomers called nuleotides
• DNA and RNA are nucleic acids

• substrate binds to the enzyme at the active site, forming an enzyme-substrate complex
• substrate binds to the enzyme through noncovalent interactions 

• inhibitor structure resembles substrate structure
• inhibitor does not alter the maximum reaction rate

• inhibitor distorts the shape of the enzyme
• inhibitor binds noncovalently at other than active site 

• the monosaccharide present in DNA
• beta-furanose form 

• contain two heterocyclic rings
• contain four ting nitrogens 

• contains one heterocyclic ring
• contains only two ring nitrogens

P—O—C

• both DNA strands are duplicated
• semi-conservative
• uses DNA polymerase

• amino acids added to peptide chain
• requires tRNA
• ribosomes 
• RNA to protien

• anticodon
• smallest RNA molecule
• transports amino acids 

• carries genetic information from nucleus to cytoplasm 
• contains the sequence of codons that determines the order of amino acids in the protein
• initiation begins with mRNA bindind to the ribosome

• the new codon codes for the same amino acid
• substitution of one base: a codon is changed from UAU to UAC
• a base substitution does not have any noticeable effects 

• the new codon codes for a different amino acid
• substitution of one base: a codon is changed from GAG to GUG
• substitution of one base: a codon is changed from CAC to CGC
• a person makes a protein of normal length but with altered function 

• the new codon is a stop codon
• subtitution of UGA for a codon
• a person makes a truncated, nonfunctional protein 

• Arginine - Arg - R - essential
• Histidine - His - H - essential
• Lysine - Lys - K - essential

• Aspartic acid - Asp - D
• Glutamic acid - Glu - E 

• Isoleucine
• leucine
• methionine
• phenylalanine
• threonine
• tryptophan
• valine
• arginine
• histidine
• lysine 

• the N—H and the C=O bonds point along the axis of teh helix in opposite directions
• there are 3.6 amino acids  in each turn of the helix
• the C=O group of one amino acid is hydrogen bonded to an N—H group four amino acid residues farther along the chain  

hemoglobin

myglobin

• found in hair, hooves, nails skin, and wool
• nonpolar amino acids exten outwrd from the helix
• insoluble in water
• super coil or superhelix

• most abundant protein
• connective tissues
• glycine and proline are are large fraction of its amino acid residues
• left-handed helis
• right-handed super-helix or triple-helix 

The ammonium cation loses a proton and the amino acid has a net negative charge

(NH3+ becomes NH2)

• transfer RNA brings specific amino acids to the ribosomes for protein synthesis
• is drawn as a cloverleaf shape

• is the synthesis of mRNA from DNA
• DNA splits and the template strand used to make RNA
• proceeds from the 3' end to the 5' end
• U replaces T on the mRNA strand