Mastering quizz Ch 21

Which of the findings of the Human Genome Project were contrary to initial expectations? Select all that apply. -Ninety-three percent of multi-exon human genes have alternatively spliced forms. -The human genome contains 3,000 Mb. -The human genome contains fewer than 21,000 genes.

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

How do transposons differ from retrotransposons? Select all that apply: -Retrotransposons reverse the effects of transposons. -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.

-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.

What is the goal of comparative genomic studies?

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

Select the correct statement(s) about genome size and density. Select all that apply. -Within eukaryotes, genome size is a reliable predictor of phenotypic complexity. -Eukaryotic genomes are larger than prokaryotic genomes. -Eukaryotes have higher gene densities than prokaryotes.

Eukaryotic genomes are larger than prokaryotic genomes.

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.

Which of the following statements about genome sizes is true? Large animals have larger genomes than plants. Species within a phylogenetic group such as flowering plants or insects have similar genome sizes. Most eukaryotes have larger genomes than most prokaryotes. The human genome is the largest and most complex. All of the above statements are true.

Most eukaryotes have larger genomes than most prokaryotes.

How do retrotransposons differ from other transposons?

Retrotransposons move via an RNA transcript, whereas other transposons do not.

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.

Identify the correct statement(s) about transposable elements. Select all that apply. -Transposable elements are called "jumping genes" because they detach from their location in DNA before reattaching in a different location. -Telomeric simple sequence DNA is made up of transposable elements. -Transposable elements and related sequences make up 44% of the human genome.

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

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

Homeotic genes: -are found only in Drosophila and other arthropods. -encode proteins that form anatomical structures in the fly. -encode transcription factors that control the expression of genes responsible for the organism's development. -are responsible for patterning during plant development. -are the only genes that contain the homeobox domain.

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? -RNA splicing -exon shuffling -gene duplication -random point mutations -histone modification

exon shuffling

The number of genes correlates with _____.

the size of the genome in prokaryotes

*One of the characteristics of retrotransposons is that: -they code for an enzyme that synthesizes DNA using an RNA template. -they contribute a significant portion of the genetic variability seen within a population of gametes. -their amplification is dependent on a retrovirus. they generally move by a cut-and-paste mechanism. they are found only in animal cells.

they code for an enzyme that synthesizes DNA using an RNA template.

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

Bioinformatics includes all of the following except: -developing computer-based tools for genome analysis. -using mathematical tools to make sense of biological systems. -using molecular biology to combine DNA from two different sources in a test tube. -analyzing protein interactions in a species. -using computer programs to align DNA sequences.

using molecular biology to combine DNA from two different sources in a test tube.