The peptide bond in proteins is a) nonpolar, and fixed in a trans conformation. b) nonpolar, but rotates to three preferred dihedral angles. c) planar, and usually found in a trans conformation. d) planar, but rotates to three preferred dihedral angles.
1 3972If the enthalpy change for a reaction is zero, DG? is equal to: a) DH? b) lnKeq c) TDS? d) -TDS?
1 3840The nucleophile in the first stage of the serine protease mechanism is a) H2O b) the carboxyl of Asp 102 c) the hydroxyl of Ser 195 d) the imidazole of His 57
2156The elution volume of an enzyme on a gel filtration column can be predicted from a) its enzyme activity b) its protein absorbance at 280 nm c) subunit composition and monomer molecular mass(es) d) Choices a) and b) are both correct.
3274DNA binding by proteins with the helix-turn-helix (HTH) motif does not involve a) altered stacking of the DNA at the center of symmetry. b) hydrogen bonds, salt bridges, and van der Waals contacts. c) interactions with base pairs in the major groove of DNA. d) interactions with the sugar-phosphate backbone of DNA.
2145The two exonuclease activities of DNA polymerase I a) are coupled during the formation of "gapped DNA". b) degrade DNA in a 5' --> 3' direction. c) degrade DNA in a 3' --> 5' direction. d) occur at two different active sites.
1 3317A principal difference between prokaryotic and eukaryotic DNA replication is a) completely different proteins/enzymes in eukaryotes b) multiple origins in eukaryotes c) no requirement for topoisomerase activity in prokaryotes d) the absence of a nucleus in prokaryotes
9 36883When s subunit dissociates from an initiated RNA polymerase, a) it can bind a core enzyme to reform holoenzyme. b) it hydrolyzes ATP until rebound by core enzyme. c) it leaves behind an elongating species complexed with Rho factor. d) it remains bound to the promoter consensus sequence.
1 3814The junction between the two helical portions of tRNA is stabilized by many non-standard base-base interactions between residues in the a) anticodon and CCA ends. b) helical stems of the D and Anticodon stems. c) loops of the Anticodon and Acceptor stem. d) loops of the TYC and D arms.
1 4013On the ribosome, mRNA binds ____; the peptidyl transferase reaction occurs ____. a) to the large subunit; on the small subunit. b) to the small subunit; on the large subunit. c) between the subunits; on the large subunit. d) between the subunits; on the small subunit.
2 6173According to the fluid mosaic model of cell membranes, which type of molecule spans the membrane from its inner to outer surface? a) cholesterol b) phospholipid c) protein d) triacylglycerol
1 5505Post New Bio Chemistry Questions
What is heat of combustion?
How do you call the geometrical isomerism, similar groups are present on same side?
What are pentoses? Are nucleotides formed of only one type of pentose?
What is addition reaction?
What is markownikoff’s rule?
Why ethylene undergoes electrophilic addition reactions?
Give the formula for Peral Ash?
What is the bond angle of phosphorous?
What are zymogens?
Name the 1st synthetic organic compound that was prepared from its elements is?
How does a random coil differ from an irregularly structured region?
How do peptides react with cyanogen bromide?
What are respectively some remarkable functions of albumin?
What is the difference between essential and natural amino acids?
What are respectively some remarkable functions of myosin, cd4, albumin, keratin, immunoglobulin, reverse transcriptase, hemoglobin, and insulin?