Mastering Biology - Chapter 21

The TP53 gene of chromosome 17 codes for a protein _____.

involved in the regulation of the cell cycle

Bioinformatics includes all of the following

developing computer-based tools for genome analysis. using computer programs to align DNA sequences. analyzing protein interactions in a species. using mathematical tools to make sense of biological systems.

Given a DNA molecule with the sequence of bases 5'-CATCTA-3', what would be the sequence of the complementary strand?

5'-TAGATG-3'

Genome size and density

Eukaryotic genomes are larger than prokaryotic genomes.

Consider a diploid cell with homologous pair of chromosomes, each with alleles of the two genes F and H located in close proximity to each other. The maternal chromosome has the dominant allele of each gene (F and H) and the paternal chromosome has the recessive allele of each gene (f and h). After meiosis is completed, what are the potential genotypes of the four gametes formed from this parent cell?

FH, Fh, fH, fh

What gene codes for a protein that plays a role in growth?

GH1

What are Hox genes?

Hox genes encode transcription factors with a DNA-binding domain called a homeo box, and regulate development of the vertebrate body plan.

How has gene duplication played a critical role in evolution?

It produces redundant copies of existing genes, which are then free to mutate and adopt new functions. The prevalence of multigene families attests to the importance of gene duplication

What gene codes for a protein that plays a role in white blood cell function?

MPO

Which of the following statements about genome sizes is true?

Most eukaryotes have larger genomes than most prokaryotes.

Which of the findings of the Human Genome Project were contrary to initial expectations?

Ninety-three percent of multi-exon human genes have alternatively spliced forms. The human genome contains fewer than 21,000 genes.

Once researchers identified DNA as the unit of inheritance (the gene), they asked how information was transferred from the DNA in the eukaryotic nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly summarizes the mechanism of information transfer in eukaryotes that results in protein synthesis?

RNA is transcribed from a gene in the nucleus and is processed into mRNA. The mRNA is then transported to a ribosome in the cytoplasm and translated into a specific sequence of amino acids.

How do retrotransposons differ from other transposons?

Retrotransposons move via an RNA transcript, whereas other transposons do not. Retrotransposons are transcribed into an RNA intermediate which is then converted back into DNA by reverse transcriptase

Why is the outdated term "junk DNA" a misnomer for noncoding regions of the human genome?

The conservation of "junk DNA" sequences in diverse genomes suggests that they have important functions.

Mendel studied flower color in peas, which varies between two traits—purple flowers and white flowers. There are two alleles of the flower color gene: the dominant purple (P) allele and the recessive (p) allele. What is the molecular basis for dominance of the purple allele in a plant that has both alleles (heterozygous, or genotype Pp)?

The recessive allele has a mutation that does not allow it to be expressed, but enough purple pigment is made by expression of the dominant allele that the flower is purple.

Identify the correct statement(s) about transposable elements.

Transposable elements and related sequences make up 44% of the human genome.

How do transposons differ from retrotransposons?

Transposons may or may not leave a copy behind at the original site, whereas retrotransposons always leave a copy behind at the original site. Transposons move by means of a DNA intermediate, whereas retrotransposons move by means of an RNA intermediate

By what mechanism might transposons contribute to gene duplication?

Transposons may promote unequal crossing over during meiosis.

BLAST is a computational tool used by genome biologists to _____.

compare a given DNA or protein sequence to all other DNA or protein sequences in a database

Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this?

differential gene regulation over time

Homeotic genes

encode transcription factors that control the expression of genes responsible for the organism's development.

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?

exon shuffling

the RP13 gene of chromosome 17 codes for a protein _____.

involved in eye development

For mapping studies of genomes, most of which were far along before 2000, the three-stage method was often used. Which of the following is the usual order in which the stages were performed, assuming some overlap of the three?

linkage map, physical map, sequencing of fragments

The number of genes correlates with _____.

the size of the genome in prokaryotes

What is the goal of comparative genomic studies?

to identify homologues in model organisms for genes involved in human disease, to identify genes that are important for evolution of a particular species, to study how genomes evolve, to study genetic variation within a species or a population

What was the main goal of the Human Genome Project (HGP)?

to map all the human genes and determine the nucleotide sequence of the entire human genome

What type of noncoding DNA comprises the largest portion of multicellular eukaryotic genomes?

transposons