Bio Chemistry Interview Questions
Questions Answers Views Company eMail

What is a plasmalogen? What do plasmalogens do?

1 5601

What is the role of PAPS?

1 2222

what is Alzheimer's disease?what are its symptoms?

1 3254




Compare and contrast feedback inhibition and enzyme repression?

8183

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 1794

If the enthalpy change for a reaction is zero, DG? is equal to: a) DH? b) lnKeq c) TDS? d) -TDS?

1 1985

The 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

960

The 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.

1937




DNA 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.

913

The 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 1569

A 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 30270

When 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 1873

The 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 1567

On 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 2885

According 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

PH.D Interview,

1 2870


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Un-Answered Questions { Bio Chemistry }

A 3.00 * 10-6M solution in a 1.0 cm cuvette read 16 % T at 620nm. What were the absorbance and the molar absorbancy index of the solution?

899


Two children have a neurological disorder. When cells from the two patients were fused to form heterokaryons containing nuclei from both patients and cultured, the cells displayed normal metabolism. Cells from either patient exhibited abnormal metabolism when cultured separately.what does these results indicate?

968


bane the by products when crude oil is refined by distillation

989


What do you like LEAST & MOST about your current position?

3098


mutarotation is observed when phenol and pyridine both are present but phenol or pyridine alone cannot show mutarotation-explain why?

2982






Why is the t-butyloxycarbonyl protecting group such a good choice for amino acid synthesis?

975


What is the structural formula of molybdenum blue?

2313


which fat soluble vitamin has co-enzymic function?

790


I have given the protocol for the cyclodextrin glygosyl transferase assay: One ml of appropriately diluted enzyme sample was incubated at 60 °C for 15 min with 5 ml of 1% (w/v) gelatinized soluble starch in 50 mM, 7.0-pH Tris–HCl buffer. Reaction was terminated by boiling the reaction mixture for 3 min and reaction volume was made to 10 ml with distilled water. Two ml of above reaction mixture was withdrawn and mixed with 3 ml of Tris–HCl buffer, 5 ml of 125 mM Na2CO3, and 0.5 ml of phenolphthalein (25 mg phenolphthalein/100 ml absolute alcohol). Absorbance was measured at 550 nm. The percent decrease of sample was calculated with respect to control containing 5 ml of buffer, 5 ml of sodium carbonate and 0.5 ml of phenolphthalein. where Acontrol = absorbance of control and Atest = absorbance of sample. The amount of β-cyclodextrin (β-CD) produced was estimated from the standard graph of 0–500 μg/ml β-CD concentration against % decrease in absorbance. One unit of CGTase was defined as the amount of enzyme required to produce 1 μm of β-CD/min. Please can you suggest me the formula for the defination given in the last line

926


What are the structures of the products of this reaction, and how are they identified?

918


How is the actual free energy change for a process related to the standard free energy change?

1499


what is familiar hypercholesterolemia?

1243


what is your passion?

856


does glucagon secretion induce sleep in teenagers?why?

1026


What is the difference between Phospholipids and phosphosphingosides?

1958