Chapter 1 Multiple Choice Questions

. You isolate a sample containing only a specific protein. By heating it, you denature the protein. It will reform a specific 'native' state

only in the presence of a specific catalyst that promotes folding.

only under a limited set of conditions of salt concentration and temperature.

only within a cell or organelle.

under any conditions.

. Which of the following is NOT a function of some proteins in a cell?

Containing information for transmission of hereditary information

Control of expression of one or more genes

Contributing to transport of ions or molecules across membranes

Catalysis of a metabolic reaction

. For most proteins, to carry out its function

two molecules of the protein must form a dimer.

the protein must adopt a specific three-dimensional structure.

the protein must contain a specific cofactor, such as NAD⁺.

the protein must be in the cytoplasm of a cell.

. Isoelectric focusing separates proteins according to

denaturation temperature.

solubility.

isoelectric point.

molecular weight.

. The secondary structures of all proteins contain

only α-helices.

only β-sheets.

α-helices and β-sheets.

None of the other choices is correct.

. A domain in a protein is

a region of the polypeptide chain that forms a locally compact substructure.

a region of the polypeptide chain that necessarily appears several times consecutively in the same protein.

a region of the polypeptide chain that is encoded in the DNA by a single exon.

a part of a multimeric protein containing a complete single polypeptide chain.

. Possible clinical applications of sequencing of human genomic DNA include all except one of the following. That is, which one is NOT a possible clinical application of human genomic DNA sequencing?

Pharmacogenomics: the decision about how to treat a disease based on the patient's genome sequence

Following mutations in a virus that infects humans which is spreading through a population

Counselling of potential parents of the likelihood of problems affecting a foetus they might conceive

Detection of genes for mutant proteins for diagnosis of causes of disease

. A single amino-acid substitution in a human protein

could not be sufficient to change the structure and function of the protein.

might cause slight changes in structure and function, but could not completely prevent the protein from forming a native state.

might cause slight changes in structure and function, but could not completely prevent the protei from forming interactions it normally makes with other proteins.

may possibly give rise to a disease.

. Which of the following is NOT an effective mechanism of protein evolution?

Point mutations

Deletion of a region in the interior of an intron

Mixing and matching of domains

Insertions and deletions of short regions of amino acids

. A database collecting a certain type of information about proteins should provide

curation of the data to check accuracy and convert to a standard format, but none of the other choices.

a record of the source of the data - the 'provenance' - but none of the other choices.

the database should provide all of the other choices.

provide information-retrieval facilities to help select particular items from the database, but none of the other choices.

. In which of way does a liver cell in your body differ from a brain cell?

Genes for particular proteins appear on different chromosomes in liver cells and brain cells.

The two cells show different patterns of protein expression.

The DNA sequences of the two cells differ substantially.

Only liver cells actively send signals to adjacent cells.

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