CH. 1 & 9 QUIZ

Question 1

The more nucleotides there are in an organism’s genome, the more genes there will be in its genome

Answer 1

false

Question 2

Most genes in vertebrates are unique, and only few genes are members of multigene families

Answer 2

true

Question 3

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.

Answer 3

true

Question 4

While almost all DNA duplication leads to a new functional gene, few duplications are lost or become pseudogenes.

Answer 4

true

Question 5

A pseudogene, such as one coding for microRNAs, is very similar to a functional gene but cannot be expressed because of mutations

Answer 5

false

Question 6

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.

Answer 6

true

Question 7

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.

Answer 7

true

Question 8

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?

Answer 8

Any two individuals (other than identical twins) will generally have more than 3 million genetic differences in their genomes.

Question 9

How can comparative genomics assist in the treatment of HIV?

Answer 9

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.

Question 10

The human genome project led to the discovery that much of the genome consists of repeated sequences of nucleotides.

Answer 10

These are thought to function as protection for ends of DNA and as centromere attachment sites

Question 11

All highly conserved stretches of DNA in the genome are transcribed into RNA and most mutations and genome alterations have neutral consequences.

Answer 11

false

Question 12

Which statement was discovered by information gained from the human genome project?

Answer 12

Large sections of the human genome do not code for a polypeptide

Question 13

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).

Answer 13

true

Question 14

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.

Answer 14

false

Question 15

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.

Answer 15

true

Question 16

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.

Answer 16

false

Question 17

Transposable elements make up 44% of the human genome. What is thought to be their function?

Answer 17

We are not sure of their function

Question 18

Because gene duplication can occur when crossover events occur, genes are always duplicated onto homologous chromosomes.

Answer 18

false

Question 19

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?

Answer 19

It’s genome seems to have lost sequences faster than it has gained sequence over time

Question 20

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

Answer 20

of designer drugs that are made to match one specific individual’s DNA profile

Question 21

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.

Answer 21

DNA replication

Question 22

Which of the following terms applies to the study of all of the proteins produced by an organism?

Answer 22

Proteomics

Question 23

To meet a challenge or develop a new function, evolution essentially builds from scratch to find the best possible solution.

Answer 23

false

Question 24

Which species has an estimated 6,300 genes in its genome?

Answer 24

yeast

Question 25

By some estimates, 20% of the genomic DNA in some bacterial species arose by horizontal gene transfer.

Answer 25

true

Question 26

All of the following are benefits of sequencing the human genome except

Answer 26

the discovery of the chemical makeup of DNA

Question 27

Proteins required for growth, metabolism, and cell division are more highly conserved than those involved in development and in response to the environment.

Answer 27

true

Question 28

Which of the following generalities about genomes is true?

Answer 28

All vertebrate genomes contain roughly the same number of genes.

Question 29

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%).

Answer 29

true

Question 30

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.

Answer 30

true

Question 31

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.

Answer 31

true

Question 32

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.

Answer 32

false

Question 33

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?

Answer 33

Modern vertebrate species evolved from the same ancestors and a large portion of their genome is conserved.

Question 34

All mutations in an asexually reproducing single-celled organism are passed on to progeny.

Answer 34

true

Question 35

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.

Answer 35

true

Question 36

Horizontal transfer is very rare and thus has had little influence on the genomes of bacteria.

Answer 36

false

Question 37

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.

Answer 37

false