YABA COLLEGE OF TECHNOLOGY
SCHOOL OF SCIENCE
DEPARTMENT OF BIOLOGICAL SCIENCE
2ND SEMESTER EXAMINATIONS 2017/2018 SESSION
CLASS: ND I (PT| Biological Science
COURSE TITLE: Genetics
SECTION A: ANSWER QUESTION ONE (1) AND ANY OTHER QUESTION FROM
PAPER CODE: STB 212
TIME: 2HRS
COURSE UNIT:2.
THIS SECTION - QUESTION ONE (1) IS COMPULSORY.
Section A
QUESTION ONE
(aji. Explain the term Genetics? Outline and explain its major branches
ii. In the garden pea, Mendel found that yellow seed colour garden pea (Pisium sativum)
was dominant to green (Y>y) and round seed shape was dominant to wrinkled (S>s).
What phenotypic and genotypic ratio would be expected in the F2 from a cross of a pure
yellow round and green wrinkled garden pea seeds?
(b). Differentiate between each of the following
i. Phenotype and Genotype
ii. Diploid and Haploid
Ii. Homozygotes and Heterozygote
iv. Metacentric and Acrocentric
v. Euploidy and Aneuploid
(c). In the ABO blood group system in human I and I" are Codominant and buth are
dominant to 1°. In a paternity dispute, a type AB woman claimed that one of four men was
the father of her type A child. Which of the following men could be the father of the child
on the basis of the evidence given? Using the principle of genetics give an accurate evidence
of proof of paternity and justify your reasons.
(d). In the fruitfly, Drosophia melanogasterthe gene for white eyes is sex linked recessive, w.
its wild type, w gives dull red eyes. The gene for black body, b, is an autosomal
recessive and contrasts its wild type allele, b' which gives a gray body. For across
between female who are.heterozygous for both genes and white-eyes black-bodies.
miales, Determine the phenotypes of the progeny and in what proportions they
occur.
QUESTION TWO
Explain genetic engincering and outline its basic steps.
What are restriction enzymes? List five types of restriction enzymes and identity
their sources and sources and cleavage site.
b. Describe the importance of polymerase chain reaction (PCR).
c) Explain each of the following: Codominance, Lethal Alletes, Crossing over,
pleiotropy.
d. if the DNA of an Escherichia coli has 4.2x10 Nucieotides pairs in its DNA and i1 ti
averagecistron contain 1500 nucleotides pairs, how many cistron does it possess?
QUESTION THREE
(a) i. Explain the term genetic disorder and highlights with examples.
ii. Explain why metaphase is the best stage used for genetics study of ehromosomes.
(b) If the base sequence of one strand of DNA is CAG,CAT, CAC, TAG, what wili be
i. Complimentary DNA strand.
ii. Complimentary RNA strand.
iii. State Hardy Weinberg princeiple.
C. In a group of student, about 36 percent could roll their tongues, a trait determine by a dominant gene. The other 64 percent of the student were non-rollers. Calculate the
frequencies of the gene (R) for tongue rolling and its recessive allele (r) for non-roling.
d. Corn(Zea mays) has a diploid number of 20. How many chromosomes would he expected in the following:
i. A metotic produet fmierospore or megaspere
iÑ—. A mature embryo sac
iii. An endosperm cell
SECTION B: ANSWER QUESTION FOUR (4) AND ANY OTHER QUESTION
FROM THIS SECTION-QUESTION FOUR (4) IS COMPULSORY.
4).
Answer the following questions in your auswer booklet.
i. Sex in man and other mammals Is determined by X & Y chromosomes just as --& ---- chromosomes determine the sex in birds.
ii. In birds, mate and female sexes are represented by chromosomes respectively.
iii. X-linked diseases are mostly manifested in the ------offspring.
iv. Y-linked diseases are only manifested in the- ------ offspring.
V. X-linked diseases are only manifested in a female offspring if the genes are present in a ----- state.
Vi. All the foliowing are factors cause changes in allele frequency in a population
------ state except: