Which one of the following cannot be explained on the basis of Mendel’s Law of Dominance?
[A] The discrete unit controlling a particular character is called a factor
[B] Out of one pair of factors one is dominant, and the other recessive
[C] Alleles do not show any blending and both the characters recover as such in F2 generation
[D] Factors occur in pairs
The genotype of a plant showing the dominant phenotype can be determined by:
[A] Test cross
[B] Dihybrid cross
[C] Pedigree analysis
[D] Back cross
ABO blood groups in humans are controlled by the gene I. It has three alleles – IA,IB and i. Since there are three different alleles, six different genotypes are possible. How many pheno-types can occur?
Select the correct statement from the ones given below with respect to dihybrid cross.
[A] Tightly linked genes on the same chromosome show higher recombinations
[B] Genes far apart on the same chromosome show very few recombinations
[C] Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones
[D] Tightly linked genes on the same chromosome show very few recombinations
Which one of the following conditions correctly describes the manner of determining the sex in the given example?
[A] XO type of sex chromosomes determine male sex in grasshopper
[B] XO condition in humans as found in Turner syndrome, determines female sex
[C] Homozygous sex chromosomes (XX) produce male in Drosophila
[D] Homozygous sex chromosomes (ZZ) determine female sex in birds
A collection of plants and seeds, having diverse alleles of all the genes of a crop, is called
[B] Gene library
When two unrelated individuals or lines are crossed, the performance of F1 hybrid is often superior to both its parents. This phenomenon is called:
Test cross in plants or in Drosophila involves crossing
[A] Between two genotypes with recessive trait
[B] Between two F1 hybrids
[C] The F 1hybrid with a double recessive genotype
[D] Between two genotype with dominant trait
Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?
[A] Two X chromosome
[B] Only one Y chromosome
[C] Only one X chromosome
[D] One X and one Y chromosome
Read the following four statements (A – D):
(A) In transcription, adenosine pairs with uracil
(B) Regulation of lac operon by represser is referred to as positive regulation
(C) The human genome has approximately 50,000 genes
(D) Haemophilia is a sex-linked recessive disease
How many of the above statements are right?
A test cross is carried out to:
[A] Predict whether two traits are linked
[B] Assess the number of alleles of a gene
[C] Determine whether two species or varieties will breed successfully
[D] Determine the genotype of a plant at F2
A normal-visioned man whose father was colour-blind, marries a women whose father was also colour-blind. They have their first child as a daughter. What are the chances that this child would be colour-blind”.
[B] Zero percent
F2 generation in a Mendelion cross showed that both genotypic and phenotypic rations are same as 1:2: It represents a case of:
[B] Dihybrid cross
[C] Monohybrid cross with complete dominance
[D] Monohybrid cross with incomplete dominance
Which of the following statements is not true of two genes that shows 50% recombination frequency?
[A] The genes may be on different chromosomes
[B] The genes are tightly linked
[C] The genes show independent assortment
[D] If the genes are present on the same chromosome, they undergo more than one crossovers in every meiosis
Variation in gene frequencies within populations can occur by change rather than by natural selection. This is referred to as:
[A] Genetic flow
[B] Genetic drift
[C] Random mating
[D] Genetic load
If two persons with ‘AB’ blood group marry and have sufficiently large number of children, these children could be classified as ‘A’ blood group: ‘AB’ blood group: ‘B’ blood group in 1:2:1 ratio. Modern technique of protein electrophoresis reveals presence of both ‘A’ and ‘B’ type proteins in ‘AB’ blood group individuals. This is an example of:
[B] Incomplete dominance
[C] Partial dominance
[D] Complete dominance
Which Mendelian idea is depicted by a cross in which the F1 generation resembles both the parents?
[A] Incomplete dominance
[B] Law of dominance
[C] Inheritance of one gene