Exam I Genetics PCB3063 Form 1 Fall 2013
1. Gregor Mendel selected traits which could be easily and unambiguously sorted into two classes. Each trait such as seed shape was first bred into true breeding lines or Parental Cross
F2 Phenotypic Ratio
Round x Wrinkled Seed
5474 Round:1850 Wrinkled
Yellow x Green Seeds
6022 Yellow:2001 Green
Red x White Flowers
705 Red:224 White
Tall x Dwarf Plants
l787 Tall:227 Dwarf
varieties; these were crossed to produce the first filial or F1 generation. The F1s were, then, intercrossed to produce the data in this table. Mendel’s results were very different from the predicted results under the common theory of inheritance in the nineteenth century. For example the F1 of a cross between red flowers and white flowers should have been _____. a. red b. white c. pink d. variegated red and white e. yellow 2. Darwin realized that his theory of natural selection would not work unless the genetic material was particulate. If the “stuff” of inheritance was fluid matings between individuals of different phenotypes would be a blend of the parental types and variation would be lost from the population. Natural selection will not work under the blending theory of inheritance, because there would be
a. only two alleles. b. no crossing over. c. incomplete penetrance. d. insufficient variation. e. astronomical mutation rates. 3. The western honey bee or European honey bee (Apis mellifera) is a species of honey bee. The genus Apis is Latin for "bee", and mellifera comes from Latin melli- "honey" and ferre "to bear"—hence the scientific name means "honey-bearing bee". The somatic cells of haploid males contain 16 chromosomes; the somatic cells of diploid females contain _______ DNA double helices. a. 16 b. 24 c. 32 d. 82 e. 164 4. In an individual who is a Qq heterozygote the daughter cells after the first meiotic division will be a. QQ & qq b. Qq & qQ c. qQ & Qq d. Q & q e. q & Q 5. Mendelian segregation of alleles depends on the pairing and subsequent disjunction of homologous chromosomes at _________________.
a. anaphase I b. iotaphase I c. prephase I d. interphase e. metaphase I 6. Mendelian independent assortment means that nonhomolgous chromosomes segregate independently, because nonhomologous chromosomes align _______ at metaphase I. a. vertically b. horizontally c. randomly d. precisely e. modally 7. The human ABO blood type codominant alleles A and B are dominant to O. A child who isAB is most likely to be the child of which set of parents? a. AB x O b. AO x BO c. AA x BB d. OO x BB e. AA x OO
-2- 8. In 1907, Edwin Baur began his work with the snapdragon plant Antirrhinum; he characterized the condition aurea, in which plants had golden instead of green leaves. When two aurea snapdragon plants were crossed, Baur observed a 2:1 ratio of green seedlings to yellow seedlings. Homozygous aurea plants lacked normal chlorophyll. His 2:1 ratio is explainable if the homozygous aurea plants are ___________.
a. lethal as homozygotes. b. pleitropic alleles c. epistatic d. sex-linked e. imprinted 9. At metaphase 1 a chromosome contains ___ chromatids and ___ DNA double helices. a. 2 2 b. 2 4 c. 1 1 d. 3 3 e. none of these is correct 10.
During replication a guanine is erroneously paired with an adenine on one of...
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