Sbt2254:General Genetics Question Paper
Sbt2254:General Genetics
Course:Bachelor Of Crop Protection
Institution: Meru University Of Science And Technology question papers
Exam Year:2013
QUESTION ONE (30 MARKS)
a) Identify and briefly describe any two traits that are determined by extra-nuclear inheritance in a named organism. (4 Marks) b) What are plasmids? Name three important classes of plasmids highlighting the role that they play. (4 Marks) c) Distinguish between incomplete dominance and co-dominance. (2 Marks) d) In the Chinese primrose, the flower has a centre or eye of a colour different from the remainder of the petals. Normally the eye is of medium size and yellow in colour. Other variants also occur. Very large yellow eye (“primrose Queen variety), white eye “Alexandra” and blue eye “blue moon”). The table below shows the results of certain crosses. P F F Normal x Alexandria Alexandria 3 Alexandria,1 Normal
Alexandria x primrose/queen Alexandria (Not reported) Blue moon x Normal Normal 3 Normal, 1 blue moon
Primrose Queen x blue moon Blue moon (Not reported)
i. Arrange those phenotypes in order of relative dominance. (1 Marks) ii. How many genotypes can produce the „Alexandria? phenotype? (1 Mark)
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iii. How many genotypes can produce “primrose Queen type” genotype? (1 Mark) iv. How many genotype different combinations of parental genotype will produce a progeny ratio of 3 Alexandria:1 Normal. (1 Mark) e) The cross +++/abc female X abc/abc male in the fruitfly give the following cross-over results. a – b single cross overs 5.75% b – c single cross overs 8.08% a – c double cross overs 0.25%
i. What is the coincidence? (1 Mark) ii. What is meant by the term interference? Identify regions in a chromosome where the incidence of interference is high. (3 Marks) f) Write concise notes on the following; i. Dominant epistasis. (3 Marks) ii. Dominant recessive interaction. (3 Marks) g) What are restriction enzymes? Name any two restriction enzymes. (3 Marks) h) Identify three choloroplast proteins that are encoded by cpDNA and synthesized in the choloroplast. (3 Marks)
QUESTION TWO (20 MARKS)
Discuss various sources and maintenance of variation in crop improvement. (20 Marks)
QUESTION THREE (20 MARKS)
Discuss the forces that may cause genetic drift. (20 Marks)
QUESTION FOUR (20 MARKS)
Using annotated diagram, illustrate the process of cloning using a plasmid vector. (20 Marks)
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