Biology Handout "Modern Genetics"

Transcription

1 Biology Handout "Modern Genetics" Name: Page 1 1) Which statement best describes human insulin that is produced by genetically engineered bacteria? A) This insulin is produced as a result of human insulin being inserted into bacteria cells. B) This insulin may have fewer side effects than the insulin previously extracted from the pancreas of other animals. C) This insulin will not function normally in humans because it is produced by bacteria. D) This insulin is produced as a result of exposing bacteria cells to radiation, which produces a mutation. Questions 2 through 6 refer to the following: NGORONGORO LIONS Scientists in Africa have been studying the lion population of the Ngorongoro Crater, one of the world's largest volcanic craters. It is more than 10 miles across, and the distance from the crater floor to its surrounding peaks is approximately 5,000 feet. The crater's 100-square-mile floor has ideal conditions for large numbers of wildebeests and zebras. At the start of the study, nearly 100 lions lived on the crater floor, but only about 30 of these were adults of breeding age. The crater is surrounded by the 9,650-square-mile Serengeti Plain, which has some 3,000 lions. There are a number of trails leading in and out of the crater. However, lions rarely leave the crater because of the abundant food supply, and those that attempt to enter the crater are driven out by "coalitions" of males that rule the family groups, known as prides. In 1962, because of heavy rains, the bloodsucking fly Stomoxys calcitrans was able to breed constantly for over 6 months. There were so many flies that most of the lions in the crater became covered with open, oozing sores and became so ill they were no longer able to hunt. By the time the rains stopped, the population of lions was estimated to be about 10. This created a "population bottleneck," a situation in which there is a very small gene pool with very few mating partners. By 1972, the lion population had returned to its former level. Scientists were able to determine that the entire crater population of today is descended from four females that survived the plague of flies, and four males. One or more of the males may have entered the crater from the outside, since there were too few adult males to drive out any invaders. Scientists estimate that the crater lions have lost about 10% of their genetic diversity over the last 20 years. In comparison to the Serengeti lions, the crater lions have lower reproductive rates, twice as many abnormal sperm in semen samples, and a weakened immune system. 2) The present Ngorongoro lion population has descended from A) 8 lions B) 10 lions C) 20 lions D) 30 lions 3) 4) 5) 6) 7) 8) 9) The study of the Ngorongoro lions provides an example of A) acquired characteristics B) artificial selection C) punctuated equilibrium D) geographic isolation The fly Stomoxys calcitrans is an example of a A) parasite B) saprophyte C) predator D) scavenger The reproductive abnormalities in today's population of Ngorongoro lions are most likely the result of A) polyploidy B) inbreeding C) crossing-over D) nondisjunction Which statement about lions that attempt to enter the crater from the Serengeti Plain is generally true? A) They enter the crater and form their own pride. B) They are blocked from entering the crater by mountains. C) They are driven out by males living in the crater. D) They enter the crater and join an existing pride. When a certain pure strain of fruit fly is cultured at a temperature of 16DC, all of the flies will develop straight wings. The offspring of these flies will develop curly wings when they are raised at 25DC. This pattern of development indicates that A) acquired characteristics can be passed from generation to generation B) straight-winged flies will have curly-winged offspring regardless of the environment C) curly-winged flies will have straight-winged offspring regardless of the environment D) the environment can affect the expression of certain genes A change in the order of DNA bases that code for a respiratory protein will most likely cause A) a change in the sequence of amino acids determined by the gene B) the release of antibodies by certain cells to correct the error C) the production of a starch that has a similar function D) the digestion of the altered gene by enzymes Which factor would most likely change the gene frequencies in a population? A) no migrations into or out of the population B) no mutations in the population C) selective mating throughout the population D) maintenance of a large population

2 10) 11) The diagram below represents a DNA molecule. A change in the sequence of T, G, A, and C would result in A) a sex-linked gene B) a gene mutation C) nondisjunction D) polyploidy Many squirrels in the city of Syracuse are black, rather than the typical gray. This coloration is due to the presence of a gene that codes for the production of more melanin than is produced in gray squirrels. Calculating the relative percentages of black and gray squirrels and predicting how these percentages may change in future generations would be an investigation in the field of A) genetic engineering B) cytology C) population genetics D) biotechnology 12) According to the Hardy-Weinberg principle, which factor occurring in a population would cause a change in the gene pool? A) an increased mutation rate B) migration C) maintenance of a large population D) random mating Questions 13 through 15 refer to the following: In 1973, Stanley Cohen and Herbert Boyer inserted a gene from an African clawed frog into a bacterium. The bacterium then began producing a protein directed by the code found on the inserted frog gene. 13) 14) 15) 16) 17) 18) 19) Page 2 Additional copies of the bacterium containing the frog gene could be produced by A) cross-pollination B) inbreeding C) grafting D) asexual reproduction The newly synthesized genetic material in the bacterium is known as A) a multiple allele B) a gene mutation C) messenger RNA D) recombinant DNA The procedure used by Cohen and Boyer is known as A) karyotyping B) cloning C) genetic screening D) genetic engineering Substances that increase the chance of gene alterations are known as A) adaptive agents B) mutagenic agents C) chromosomal agents D) genetic agents In an experiment, DNA from dead pathogenic bacteria was transferred into living bacteria that do not cause disease. These altered bacteria were then injected into healthy mice. These mice died of the same disease caused by the original pathogens. Based on this information, which statement would be a valid conclusion? A) DNA from a dead organism can become active in another organism. B) DNA changes the organism receiving the injection into the original organism. C) DNA is present only in living organisms. D) DNA functions only in the original organism of which it was a part. Individual cells can be isolated from a mature plant and grown with special mixtures of growth hormones to produce a number of genetically identical plants. This process is known as A) cloning B) selective breeding C) recombinant DNA technology D) meiotic division Which statement is true regarding an alteration or change in DNA? A) It is always passed on to offspring. B) It is always known as a mutation. C) It is always advantageous to an individual. D) It is always detected by the process of chromatography.

3 Page 3 20) Sometimes a section of a chromosome is lost during meiosis. This loss results in a change in genetic material known as A) crossing-over B) a deletion C) replication D) polyploidy The Hardy-Weinberg principle would most likely be used in a study of A) ecological succession B) embryological development C) population genetics D) endocrine regulation When deoxyribonucleic acids from two different species are joined together, the newly formed molecule is known as A) messenger RNA B) recombinant DNA C) transfer RNA D) mitochondrial DNA Changes in the genetic material in sex cells are mutations that A) may be transmitted to the next generation B) cannot affect the organism or its offspring C) are always sex-linked D) are always eliminated during meiosis In a population of red squirrels, the sum of all the genes that can he passed on to the offspring is known as the A) gene pool B) gene frequency C) migration rate D) mutation frequency Because x-rays and ultraviolet light can change the chemical nature of DNA, they are known as A) hydrolytic enzymes B) toxic wastes C) mutagenic agents D) growth regulators A gene mutation may be transmitted to offspring if the mutation occurs within A) muscle cells B) blood cells C) an egg cell D) cells of the uterus Following exposure to x-rays, the members of a colony of fruit flies are most likely to show an increase in A) bone growth B) chlorophyll production C) mutation rate D) food consumption 28) The diagrams below represent some steps in a procedure used in biotechnology. 21) 22) 23) 24) 25) 26) 27) 29) 30) Letters X and Y represent the A) hormones that stimulate the replication of bacterial DNA B) gases needed to produce the energy required for gene manipulation C) hormones that trigger rapid mutation of genetic information D) biochemical catalysts involved in the insertion of genes into other organisms Scientific studies show that identical twins who were separated at birth and raised in different homes may vary in height, weight, and intelligence. The most probable explanation for these differences is that A) environments in which they were raised were different enough to affect the expression of their genes B) original genes of each twin increased in number as they developed C) one twin received genes only from the mother while the other twin received genes only from the father D) environments in which they were raised were different enough to change the genetic makeup of both individuals In Siamese cats, the fur on the ears, paws, tail, and face is usually black or brown, while the rest of the body fur is almost white. If a Siamese cat is kept indoors where it is warm, it may grow fur that is almost white on the ears, paws, tail, and face, while a Siamese cat that stays outside where it is cold, will grow fur that is quite dark on these areas. The best explanation for these changes in fur color is that A) the gene for fur color is modified by interactions with the environment B) skin cells that produce pigments have a higher mutation rate than other cells C) an environmental factor influences the expression of this inherited trait D) the location of pigment-producing cells determines the DNA code of the genes

4 31) After a series of cell divisions, an embryo develops different types of body cells such as muscle cells, nerve cells, and blood cells. This development occurs because A) some parts of the genetic materials are lost as a result of fertilization B) the genetic code changes as the cells divide C) different segments of the genetic instructions are used to produce different types of cells D) different genetic instructions are synthesized to meet the needs of new types of cells 32) The gene pool of a large population of organisms living on an isolated island was analyzed for gene frequencies. The term "gene frequency" refers to the A) percentage of dominant alleles for several traits in a population B) number of dominant phenotypes present C) percentage of each allele for a particular trait in a population D) number of recessive genotypes present Questions 33 through 35 refer to the following: 36) 37) A great deal of information can now be obtained about the future health of people by examining the genetic makeup of their cells. There are concerns that this information could be used to deny an individual health insurance or employment. These concerns best illustrate that A) acquiring too much knowledge in human genetics will discourage future research in that area B) scientific explanations depend upon evidence collected from a single source C) while science provides knowledge, values are essential to making ethical decisions using this knowledge D) scientific inquiry involves the collection of information from a large number of sources Which diagram represents a pair of homologous chromosomes? A) Page 4 For many generations, a particular species of snail has lived in an isolated pond. Some members of the species have light-colored shells and some have dark-colored shells. During this time, the species has been producing large numbers of offspring through random mating, and no migration has occurred. 33) A change in the environment of the pond caused the light-colored shells to become an important survival trait, and the number of light-colored snails increased. This situation will most likely cause A) a change in the frequency of the genes for shell color B) an increase in the number of ribosomes in the cells of the snail C) the extinction of this species of snail D) the addition of a fifth nitrogenous base to the DNA of the snails 34) All of the snails of this species living in the pond may be classified as A) a biome B) a community C) a population D) an ecosystem 35) The total of all the inheritable genes found in these snails is referred to as a A) karyotype B) gene pool C) pedigree D) phenotypic ratio 38) 39) B) C) D) What will happen if a base sequence of a strand of DNA is changed from A-T-G to A-T-C? A) The t-rna will be changed from U-A-C to T-A-C. B) The m-rna will be changed from T-U-C to T-U-G. C) The m-rna will be changed from U-A-C to U-A-G. D) The t-rna will be changed from C-A-U to C-A-C. To detect some genetic disorders, a photograph of paired homologous chromosomes is prepared. This technique is known as A) amniocentesis B) karyotyping C) blood screening D) urine analysis

5 40) The diagram below represents the chemical pathway of a process in a human liver cell Page 5 A particular liver cell is unable to make substance C. One possible explanation for the inability of this cell to make substance C is that A) nuclear DNA was altered resulting in the cell being unable to make enzyme Y B) excess energy for step 2 prevented the conversion of substance B to substance C C) a mutation occurred causing a change in the ability of the cell to use substance C D) an excess of enzyme X was present, resulting in a decrease in the production of substance B