Terms to be familiar with before you start to solve the test: Maxam-Gilbert sequencing, Sanger sequencing, gel electrophoresis, DNA synthesis reaction, polymerase chain reaction, template, primer, DNA polymerase, deoxyribonucleoside triphosphates, orthophosphate, pyrophosphate, nucleoside monophosphates, luminescence, acid anhydride bond,…

The experiment described in this test was aimed at identifying DNA repair proteins in human and yeast cells. Terms to be familiar with before you start to solve the test: DNA repair, germline mutation, somatic mutation, inherited disease, cancer, restriction endonuclease, radioactive labeling, [alpha-[superscript 32]P]ATP, [gamma-[superscript…

Transcription termination comes in two forms in "E. coli" cells. Rho-dependent termination requires the binding of a termination protein called Rho factor to the transcriptional machinery at the terminator region, whereas Rho-independent termination is achieved by conformational changes in the transcript itself. This article presents a test…

Terms to be familiar with before you start to solve the test: growth factor signaling, epidermal growth factor, tyrosine protein kinase, tyrosine phosphorylation, ubiquitin, monoubiquitination, polyubiquitination, site-directed mutagenesis, transfection, expression vector, cDNA, immunoprecipitation, SDS-polyacrylamide gel electrophoresis, Western…

Terms to be familiar with before you start to solve the test: transcription, pre-mRNA, RNA processing, RNA transport, RNA polymerase II, direct and indirect immunofluorescence staining, cell fractionation by centrifugation, oligo(dT)-cellulose chromatography, washing and elution of the column, ribonuclease, SDS-polyacrylamide gel electrophoresis,…

Terms to be familiar with before you start to solve the test: DNA replication, nitrogen isotopes, density labeling, cesium chloride density gradient centrifugation, ultraviolet absorption, DNA denaturation, circular and linear DNA, superspiralization, superhelical DNA, and template.

This paper shows the results of an experiment in which the effects of fibroblast growth factor (FGF), actinomycin D (Act D; an inhibitor of transcription), and cycloheximide (CHX; an inhibitor of translation) were studied on the expression of two genes: a gene called "Fnk" and the gene coding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH).…

An experiment is described in this test that was designed to study the role of the cyclin B protein in a cell-free system. The work was performed in the lab of Tim Hunt who, together with Hartwell and Nurse, received the Nobel Prize in Physiology or Medicine in 2001 "for their discoveries of key chemicals that regulate the cell division cycle." It…

The term "restriction endonuclease mapping" covers a number of related techniques used to identify specific restriction enzyme recognition sites on small DNA molecules. A method for restriction endonuclease mapping of a 1,000-basepair (bp)-long DNA molecule is described in the fictitious experiment of this test. The most important fact needed to…

Terms to be familiar with before you start to solve the test: chromatin, nucleases, sucrose density gradient centrifugation, melting point, gel electrophoresis, ethidium bromide, autoradiography, Southern blotting, Northern blotting, Sanger sequencing, restriction endonucleases, exonucleases, linker DNA, chloroform extraction, nucleosomes,…

Terms to be familiar with before you start to solve the test: ion exchange chromatography, polynucleotides, oligonucleotides, radioactive labeling, template, primer, DNA polymerase, reverse transcriptase, helicase, nucleoside triphosphates, nucleoside diphosphates, nucleoside monophosphates, nucleosides, 5'-end and 3'-end, bacteriophage,…

The Nobel Prize in Physiology or Medicine in 2009 was awarded to Elizabeth H. Blackburn, Carol W. Greider, and Jack W. Szostak for the discovery of "how chromosomes are protected by telomeres and the enzyme telomerase." The discovery has important implications in the processes of cellular aging and carcinogenesis. Telomeres are satellite DNA…

Terms to be familiar with before you start to solve the test: tryptophan, transcription unit, operon, "trp" repressor, corepressor, operator, promoter, palindrome, initiation, elongation, and termination of transcription, open reading frame, coupled transcription/translation, chromosome-polysome complex. (Contains 2 figures and 1 footnote.)

Terms to be familiar with before you start to solve the test: genetic code, translation, synthetic polynucleotide, leucine, serine, filter precipitation, radioactivity measurement, template, mRNA, tRNA, rRNA, aminoacyl-tRNA synthesis, ribosomes, degeneration of the code, wobble, initiation, and elongation of protein synthesis, initiation codon.…

This paper presents a problem-solving test that deals with the regulation of the "trp" operon of "Escherichia coli." Two mutants of this operon are described: in mutant A, the operator region of the operon carries a point mutation so that it is unable to carry out its function; mutant B expresses a "trp" repressor protein unable to bind…