Question 1

What can proteomics reveal that genomics cannot?

Accepted Answer

Proteomics focuses on the study of the proteome, which is the entire set of proteins produced or modified by an organism. This allows for the identification and quantification of proteins present within a specific cell or tissue type at a given time, providing insights into the functional outcomes of gene expression that genomics alone, which studies the DNA sequence and genetic makeup, cannot reveal.

Question 2

Which of the following is a direct result of alternative splicing in eukaryotes?

Accepted Answer

Alternative splicing allows a single gene to produce multiple forms of a protein by including or excluding certain sequences of RNA. This increases the diversity of proteins that can be produced from a single gene, without the need for additional genes.

Question 3

An indigenous group uses a certain plant for medicinal purposes. Their scientists are most likely to find which of the following in the genome annotation for the medicinal plant?

Accepted Answer

Genome annotation involves identifying elements within the genome, such as genes and their functions, and can reveal sequences that show similarities with known functional domains. This can help in understanding how the plant produces compounds with medicinal properties.

Question 4

Which of the following characteristics is unique to multigene families?

Accepted Answer

Multigene families are characterized by genes whose sequences are very similar and likely arose through duplication events. This is what distinguishes them from other gene types mentioned in the options.

Question 5

Information within sequence databases, such as GenBank, could be used to perform which of the following tasks?

Accepted Answer

Sequence databases like GenBank store nucleotide sequences and their annotations. These databases can be used to compare sequences across different species, which is essential for constructing phylogenetic trees to determine evolutionary relationships, as described in option B. Other tasks listed involve gene expression analysis, which typically requires additional data types and methods beyond sequence databases.

Question 6

Crickets and fruit flies are both insects. Which of the following statements could explain why a certain cricket genome has eleven times as many base pairs as that of the fruit fly, Drosophila melanogaster?

Accepted Answer

Crickets having more noncoding DNA could explain why their genome is significantly larger than that of Drosophila melanogaster, as the size of an organism's genome is not solely determined by the number of genes or its complexity but also by the amount of noncoding DNA it contains.

Question 7

Using modern techniques of sequencing by synthesis and the shotgun approach, the sequences of entire chromosomes are determined by ________.

Accepted Answer

The correct approach involves fragmenting chromosomal DNA, sequencing those fragments, and then using computer analysis to align and overlap these sequences to reconstruct the entire chromosome. This method is central to the shotgun sequencing technique.

Question 8

Which of the following best describes metagenomics?

Accepted Answer

Metagenomics involves sequencing DNA from a community of species within the same ecosystem, allowing for the study of microbial diversity and functions without the need for individual cultures.

Question 9

Which of the following is a reason that expressed sequence tags (ESTs) aid the identification of DNA that encodes proteins?

Accepted Answer

ESTs are derived from cDNA, which is synthesized from mRNA templates. Since mRNA represents the transcribed, protein-coding regions of genes, ESTs can be used to identify DNA sequences that encode proteins.

Question 10

Based on the systems approach employed by the ENCODE project, what percentage of the genome is estimated to be transcribed at some point in at least one cell type?

Accepted Answer

The ENCODE project estimated that about 75% of the human genome is transcribed at some point in at least one cell type, indicating a much larger portion of the genome is involved in transcription than previously thought.

Question 11

Which of the following techniques would be most appropriate to test the hypothesis that humans and chimps differ in the expression of a large set of shared genes?

Accepted Answer

RNA-seq is the most appropriate technique for comparing the expression of a large set of genes between humans and chimps, as it allows for the quantification of RNA levels across the entire genome, thus directly measuring gene expression differences.

Question 12

Which of the following statements best defines proteomics?

Accepted Answer

Proteomics is the large-scale study of proteomes, which are sets of proteins produced in an organism, system, or biological context. It focuses on the identification, quantification, and study of the function of proteins and their interactions, rather than the structure of individual proteins or the genetic basis of protein production.

Question 13

Which of the following statements is a correct representation of gene density?

Accepted Answer

Humans have approximately 20,000 protein-encoding genes within a genome size of about 3,000 megabases (Mb), which accurately represents gene density.

Question 14

Which of the following describes an advantage of establishing and using a human reference genome in a bioinformatics investigation?

Accepted Answer

The human reference genome is continuously revised and updated as new data are collected, ensuring it represents the current consensus of human genetic information. This makes it a valuable tool for comparison and analysis in bioinformatics investigations.

Question 15

Which of the following processes is part of the whole-genome shotgun approach to sequencing?

Accepted Answer

The whole-genome shotgun approach involves randomly fragmenting the entire genome into smaller pieces, sequencing these fragments, and then assembling the sequences using computational methods.

Question 16

A microarray is a tool used in genetic research to determine the relative level of expression of mRNAs in a particular tissue. One use of the technology is in cancer diagnosis and treatment. Which of the following pieces of evidence would support diagnosis of a cancer due to a mutation in a tumor-suppressor gene?

Accepted Answer

Tumor suppressor genes help prevent uncontrolled cell growth. A mutation in a tumor-suppressor gene often leads to a loss of function, meaning the gene's product (in this case, mRNA and subsequently the protein it encodes) is not produced or is produced in lower quantities. This can remove the cell's ability to regulate cell division properly, leading to cancer.

Question 17

A bioinformatic gene annotation contains which of the following components?

Accepted Answer

Gene annotation involves identifying elements within a DNA sequence, such as transcription start and stop sites and RNA splicing sites, which are crucial for understanding gene structure and function.

Question 18

A long region of genomic DNA is compared with a cDNA. The cDNA sequence is identical to segments, but not all, of the genomic DNA sequence. According to these data which of the following statements best describes the genomic DNA?

Accepted Answer

The cDNA sequence being identical to segments of the genomic DNA indicates that the genomic DNA contains exons, which are the coding regions of genes that are transcribed into mRNA and then translated into protein. Introns, the non-coding regions, are spliced out during mRNA processing and are not present in cDNA.

Question 19

Which of the following statements explains the observation that the number of different proteins a vertebrate produces may be larger than the number of genes found within their genome?

Accepted Answer

Vertebrates can produce more than one polypeptide from a single gene through processes like alternative splicing, where different combinations of exons are joined together to produce multiple protein variants from a single gene.

Question 20

Which of the following statements explains why is it more difficult to identify eukaryotic genes than prokaryotic genes using genomic techniques?

Accepted Answer

Eukaryotic genes often contain introns, non-coding sequences that are spliced out of the mRNA before translation. This makes it more challenging to identify the coding regions of genes in eukaryotes compared to prokaryotes, which typically do not have introns.

Quiz 20: The Evolution of Genomes