LSFT0A3 CLASS TEST 4 - WordPress

LSFT0A3 CLASS TEST 4 2019LIFE SCIENCE 3A FETCLASS TEST 4– 2019 – TOTAL: 85SURNAME: memo STUDENT NR.QUESTION 1[16]Choose the alternative that best answers the question or completes the statement. Onlyencircle the correct letter.1.11.2Pea plants were particularly well suited for use in Mendel's breeding experiments forall of the following reasons except thatA)peas show easily observed variations in a number of characters, such as peashape and flower colour.B)it is possible to control matings between different pea plants.C)it is possible to obtain large numbers of progeny from any given cross.D)peas have an unusually long generation time.E)many of the observable characters that vary in pea plants are controlled bysingle genes.What is the difference between a monohybrid cross and a dihybrid cross?A)A monohybrid cross involves a single parent, whereas a dihybrid crossinvolves two parents.B)A monohybrid cross produces a single progeny, whereas a dihybrid crossproduces two progeny.C)A dihybrid cross involves organisms that are heterozygous for twocharacters and a monohybrid only one.D)A monohybrid cross is performed for one generation, whereas a dihybridcross is performed for two generations.E)A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a3:1 ratio.1 Page

LSFT0A3 CLASS TEST 4 20191.31.41.51.6A cross between homozygous purple-flowered and homozygous white-flowered peaplants results in offspring with purple flowers. This demonstratesA)the blending model of genetics.B)true-breeding.C)dominance.D)a dihybrid cross.E)the mistakes made by Mendel.The F1 offspring of Mendel's classic pea cross always looked like one of the twoparental varieties becauseA)one phenotype was completely dominant over another.B)each allele affected phenotypic expression.C)the traits blended together during fertilization.D)no genes interacted to produce the parental phenotype.E)different genes interacted to produce the parental phenotype.Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. ThissuggestsA)that the parents were true-breeding for contrasting traits.B)incomplete dominance.C)that a blending of traits has occurred.D)that the parents were both heterozygous.E)that each offspring has the same alleles.A sexually reproducing animal has a genotype of HhTt. Which of the followinggenotypes is possible in a gamete from this organism?A)HTB)HhC)HhTtD)TE)tt2 Page

LSFT0A3 CLASS TEST 4 20191.7When crossing an organism that is homozygous recessive for a single trait with aheterozygote, what is the chance of producing an offspring with the homozygousrecessive phenotype?A)0%B)25%C)50%D)75%E)100%Use Figure 1 and the following description to answer the questions below.In a particular plant, leaf colour is controlled by gene locus D. Plants with at least one alleleD have dark green leaves, and plants with the homozygous recessive dd genotype havelight green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, andthe F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammedin the Punnett square shown in Figure 1, where 1, 2, 3, and 4 represent the genotypescorresponding to each box within the square.Figure 11.81.9Which of the boxes marked 1-4 correspond to plants with dark leaves?A)1 onlyB)1 and 2C)2 and 3D)4 onlyE)1, 2, and 3Which of the boxes correspond to plants with a heterozygous genotype?3 Page

LSFT0A3 CLASS TEST 4 20191.101.111.121.13A)1B)1 and 2C)1, 2, and 3D)2 and 3E)2, 3, and 4Which of the plants will be true-breeding?A)1 and 4B)2 and 3C)1—4D)1 onlyE)NoneMendel was able to draw his ideas of segregation and independent assortmentbecause of the influence of which of the following?A)His reading and discussion of Darwin's Origin of Species.B)The understanding of particulate inheritance he learned from renownedscientists of his time.C)His discussions of heredity with his colleagues at major universities.D)His reading of the scientific literature current in the field.E)His experiments with the breeding of plants such as peas.Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to longtails (t). What fraction of the progeny of the cross BbTt BBtt will have black fur andlong tails?A)1/16B)3/16C)3/8D)1/2E)9/16Which describes the ABO blood group system?4 Page

LSFT0A3 CLASS TEST 4 20191.141.151.16A)Incomplete dominance.B)Multiple alleles.C)Pleiotropy.D)Complete dominance.Cystic fibrosis affects the lungs, the pancreas, the digestive system, and otherorgans, resulting in symptoms ranging from breathing difficulties to recurrentinfections. Which of the following terms best describes this?A)Incomplete dominanceB)Multiple allelesC)PleiotropyD)EpistasisWhich of the following is an example of polygenic inheritance?A)Pink flowers in snapdragonsB)The ABO blood groups in humansC)Huntington's disease in humansD)White and purple flower colour in peasE)Skin pigmentation in humansA woman has six sons. The chance that her next child will be a daughter isA)1.B)0.C)1/2.D)1/6.E)5/6.5 Page

LSFT0A3 CLASS TEST 4 2019QUESTION 2[8]Give the correct biological term for each of the following statements or definitions.2.1The study of heredity. Genetics2.2The relations between successive generations.Heredity2.3The father of Genetics.Gregory Mendel2.4The process where two contrasting, true-breeding varieties are mated. Hybridization2.5A heritable factor is now known as a gene2.6The degree of Dominance where 2 dominant alleles affect the phenotype in separate,distinguishable ways. Co-dominance2.7The gene on the Y chromosome that codes for the development of testes.SRY2.8A gene located on an X chromosome that is not related to sexual characteristic. Sexlinked geneQUESTION 33.1[39]In certain plants, tall is dominant to short, use the letter T/t to do the diagram. If aheterozygous plant is crossed with a homozygous short plant, what is the probabilitythat the offspring will be short? Show all working out by using a genetic diagram ordiagram and punnet square.(22)P1 eneration:ttGenotypes:TTtTtttttt2 x Tt2 x ttPhenotypes: 2 x Tall plants and 2 x Short plantsTherefore a 50% chance of offspring being short plants6 Page

LSFT0A3 CLASS TEST 4 20193.2Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color isdominant to white (r). The heterozygous condition results in pink (Rr) flower color. Adwarf, homozygous red snapdragon is crossed with a plant homozygous for tallnessand white flowers. What are the genotype and phenotype of the F1 individuals? (17)P1 i TtRrtRTtRrTtRrTtRrTtRrtRTtRrTtRrTtRrTtRrGenotype: All TtRrPhenotype: All Tall and Pink flowers.QUESTION 4[12]Match the description in column B with the term in column A, only write down the correctletter which fit with the number in column A.(12)Column A1. Gene2. AlleleColumn BA) A variant for a characterB) A cross between an individual with anunknown genotype and a homozygousrecessive individual3. CharacterC) Having two identical alleles for a gene4. TraitD) Having two different alleles for a gene5. Dominant allele E) An alternative version of a gene6. RecessiveF) An organism's appearance or observablealleletraits7. GenotypeG) A heritable unit that determines acharacter and can exist in different forms.8. PhenotypeH) Determines phenotype in a heterozygote9. HomozygousI) A heritable feature that varies amongindividuals10. HeterozygousJ) The genetic makeup of an individual11. Test crossK) A cross between individualsheterozygous for a single character12. MonohybridL) Has no effect on phenotype in acrossheterozygoteColumn A12AnswerGE3456IAHL7J89FC1011DB12K7 Page

LSFT0A3 CLASS TEST 4 2019QUESTION 5A man of unknown genotype has type B blood, his wife has type A blood (also unknowngenotype). List ALL the blood types possible for their children. (you may need to do multiplecrosses to consider the different possible genotypes of the parents).(10)I BiP1IAixMeiosisGametesIBIAiiFertilizationIiIBIAIBI BiAGenotype of F1:iIAiiiIAIBI BiIAiIiPhenotype: 1x AB blood group1 x B blood group1 x Ablood group1 x Oblood groupTherefor the children can have any of the four bloodgroups it the parents areheterozygous for blood group A and BIf the parents are homozygous for A and B blood group then the following crosswould occur:I BI BP1IAIAxMeiosisGametesIBIBIAIAFertilizationIBIB8 Page

LSFT0A3 CLASS TEST 4 2019IAIAIBIAIBIAIAIBIAIBGenotype of F1:4xIAIBPhenotype: 4 x AB blood groupNote for marker: They could have done the cross between a heterozygous father andhomozygous mother or visa versa - they just have to have at least two possiblecorrect crosses.9 Page

B) A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only one. D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. E) A monohybrid cross results .