CH. 1 & 9 QUIZ Flashcards
The more nucleotides there are in an organism’s genome, the more genes there will be in its genome
false
Most genes in vertebrates are unique, and only few genes are members of multigene families
true
The differences between multicellular organisms are largely explained by the different kinds of genes carried on their chromosomes. The increased complexity of humans compared with flies and worms is largely due to the vastly larger number of genes in humans and when and where the genes are expressed. Differences in the timing of splicing may also be a major contributor to the relative complexity of humans.
true
While almost all DNA duplication leads to a new functional gene, few duplications are lost or become pseudogenes.
true
A pseudogene, such as one coding for microRNAs, is very similar to a functional gene but cannot be expressed because of mutations
false
Evolution can work only by tinkering with the tools and materials on hand, not by starting from scratch to make completely new genes or pathways. New functions arise from the ancestral functions by a process of gradual mutational change, and thus may not represent the best possible solution to a problem.
true
All organisms need to perform a similar basic set of fundamental functions, such as those for metabolism, protein synthesis, and DNA replication. Proteins involved in these functions are shared by descent, and their evolution is constrained. Different species and cells are likely to require different developmental paths and to encounter different environmental challenges, so the proteins involved in these processes will tend to be more variable. For example, bacteria do not undergo elaborate developmental programs and so lack many of the regulators of development found in eukaryotes.
true
The nucleotide sequences between individuals differ by 0.1%, yet the human genome is made up of about 3 × 109 nucleotide pairs. Which of the following statements is true?
Any two individuals (other than identical twins) will generally have more than 3 million genetic differences in their genomes.
How can comparative genomics assist in the treatment of HIV?
Understanding the evolution of HIV in an individual will help scientist understand how the virus responds to different drug regimes and will lead to better treatments.
The human genome project led to the discovery that much of the genome consists of repeated sequences of nucleotides.
These are thought to function as protection for ends of DNA and as centromere attachment sites
All highly conserved stretches of DNA in the genome are transcribed into RNA and most mutations and genome alterations have neutral consequences.
false
Which statement was discovered by information gained from the human genome project?
Large sections of the human genome do not code for a polypeptide
Mutations are carried in the genetic material, and the only genetic material passed along to the offspring of a sexually reproducing organism comes from a germ-line cell (not a somatic cell).
true
Because the fly Drosophila melanogaster and humans diverged from a common ancestor so long ago, a gene in the fly will show more similarity to another gene from the same species than it will to a human gene.
false
Most single-nucleotide polymorphisms (SNP) cause no observable functional differences between individual humans. There are repeats in many locations throughout the genome. Because the number of repeats at a given location varies greatly between individuals and families, it can be used as an identifying characteristic to match two samples (such as blood samples) from the same or related individuals. Nearly all single-nucleotide polymorphisms have no effect on the appearance or behavior of the individual, but a few cause important differences.
true
In an evolutionary sense, somatic cells exist only to help propagate germ-line cells therefore a mutation that arises in a mother’s somatic cell often causes a disease in her daughter.
false
Transposable elements make up 44% of the human genome. What is thought to be their function?
We are not sure of their function
Because gene duplication can occur when crossover events occur, genes are always duplicated onto homologous chromosomes.
false
The puffer fish, Fugu rubripes, has a genome that is one-tenth the size of mammalian genomes. Which statements is a possible reason for this size difference?
It’s genome seems to have lost sequences faster than it has gained sequence over time
The human genome project discovered many small regions of DNA that vary among individuals called single nucleotide polymorphisms (SNPs). Certain SNP patterns change an individual’s susceptibility to disease and after response to medical treatments. This knowledge has led to the idea that
of designer drugs that are made to match one specific individual’s DNA profile
Some types of gene are more highly conserved than others since their pathways or phenomena are fundamental to the growth and proliferation of all cells, including bacteria, and thus are likely to be highly conserved from species to species. For each of the following pairs of gene functions, choose the one that is more likely to be highly conserved.
DNA replication
Which of the following terms applies to the study of all of the proteins produced by an organism?
Proteomics
To meet a challenge or develop a new function, evolution essentially builds from scratch to find the best possible solution.
false
Which species has an estimated 6,300 genes in its genome?
yeast
By some estimates, 20% of the genomic DNA in some bacterial species arose by horizontal gene transfer.
true
All of the following are benefits of sequencing the human genome except
the discovery of the chemical makeup of DNA
Proteins required for growth, metabolism, and cell division are more highly conserved than those involved in development and in response to the environment.
true
Which of the following generalities about genomes is true?
All vertebrate genomes contain roughly the same number of genes.
The human genome, is made up of more than 40% of mobile genetic elements and codes for more intron sequences than for exon sequences (about 1.5%).
true
Many highly conserved stretches of DNA are not transcribed but instead contain information critical for regulating where and when genes are expressed. The sequences that are necessary to preserve the function of the gene will not be able to undergo changes and thus are more likely to be similar between species that diverged long ago.
true
There are estimated to be approximately 20,000 pseudogenes in the human genome which look very similar to normal genes but cannot produce a full-length protein, as a result of one or more disabling mutations.
true
ntrons and transposons can act as sites where recombinational crossovers occur. Transposons can also catalyze genetic rearrangements. Rearrangements occurring within these sequences very detrimental than those occurring elsewhere in the genome.
false
The study of comparative genomics has given researchers the ability to look at multiple genomes from different species, which has led to new ideas about the evolutionary history of organisms. The conclusion is that?
Modern vertebrate species evolved from the same ancestors and a large portion of their genome is conserved.
All mutations in an asexually reproducing single-celled organism are passed on to progeny.
true
There is no necessary correlation between genome size and gene number. There are some fly genes, particularly those with a conserved function, that show much greater similarity to human genes than to another fly gene. Genome size does not necessarily correlate with evolutionary relatedness.
true
Horizontal transfer is very rare and thus has had little influence on the genomes of bacteria.
false
The intron structure of most genes among mammals is conserved while exons are mainly what is conserved between the genomes of humans and other mammals.
false
