Which of the following is a recessive trait for a character chosen by Mendel in garden pea?
1. Violet flower colour
2. Yellow pod colour
3. Axial flower position
4. Tall stem height
Genes which code for a pair of contrasting traits or slightly different forms of the same gene are known as:
1. Alleles
2. Loci
3. Cistrons
4. Introns
A test cross is done to find out:
1. Fitness of an organism
2. Genotype of a plant expressing dominant phenotype
3. The suitable parents for a Mendelian Cross
4. The hidden genotypic ratio of F2 phenotypes
The law of Segregation is based on the fact that
1. The alleles do not show any blending.
2. There is random fertilization
3. Gametes are pure for the trait
4. The zygotes are diploid
The ultimate source of allelic variation is:
1. Recombination
2. Natural selection
3. Mutation
4. Drift
In the case of co-dominance, the F1 generation resembles:
1. Dominant parent
2. Recessive parent
3. Both the parents
4. None of the parents
The number of alleles, the genotypic combinations and phenotypes in ABO system is respectively:
1. 3, 6 and 4
2. 3, 4 and 6
3. 2, 3 and 4
4. 2, 3, and 6
Suppose a gene has seven alleles. What would be the number of alleles in an individual at any instant?
1. 1.
2. 7
3. 2
4. 3
When Mendel self hybridized F1 progeny of a dihybrid cross between pure Yellow Round seeded plants and Green Wrinkled plants, he observed that yellow and green colour segregated in a ratio of:
1. 1 : 1
2. 3 : 1
3. 9 : 3 : 3 : 1
4. 1 : 2 : 1
“Chromosomes, which are seen in all dividing cells and pass from one generation to the next, are the basis for all genetic inheritance”.
This statement is credited to:
1. Watson and Crick
2. Hershey and Chase
3. Sutton and Boveri
4. Meselson and Stahl
When Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F1 progeny, the F2 ratio deviated very significantly from the 9:3:3:1 ratio. This can be attributed to the fact that:
1. The genes are located on X and Y chromosomes.
2. Fruit fly has abnormal chromosomes
3. The genes are located on the X chromosome
4. The genes exhibit incomplete dominance
Genes tightly linked on the same chromosome show:
1. Very high recombination
2. Independent assortment
3. Very low recombination
4. 50 % recombination
In humans, the mechanism of sex determination is:
1. XX – XY; male heterogamety
2. XX – XY; female heterogamety
3. XX – XO; male heterogamety
4. XX – XO; female heterogamety
A couple has a daughter. What is the probability that their next child will be a daughter?
1. 0 %
2. 25 %
3. 50 %
4. 100 %
Identify the incorrect statement:
1. In addition to recombination, mutation is another phenomenon that leads to variation in DNA.
2. Chromosomal aberrations are commonly observed in cancer cells.
3. A classical example of a point mutation is sickle cell anemia.
4. Non ionising radiations cannot be mutagens.
The point mutation in sickle cell anaemia leads to a change in codon. Identify the correct change:
1. UGA to UAA
2. GUG to GAG
3. GAG to GUG
4. UAA to UGA
In cases of Phenylketonuria:
1. The affected individual lacks an enzyme that converts the amino acid tyrosine into phenylalanine.
2. The affected individual makes an enzyme that converts the amino acid tyrosine into phenylalanine.
3. The affected individual makes an enzyme that converts the amino acid phenylalanine into tyrosine.
4. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine.
Failure of cytokinesis after telophase stage of cell division results in an increase in a whole set of chromosomes in an organism and, this phenomenon is known as:
1. Aneuploidy
2. Translocation
3. Polyploidy.
4. Inversion
Which of the following is not a feature of Down’s Syndrome?
1. It is caused by a non-disjunction in an autosome
2. The affected individual has trisomy of chromosome 21
3. The affected individual has a characteristic simian palmar crease
4. The mental development of affected individual is normal.
An individual affected by Klinefelter’s sundrome:
1. Has 47 autosomes
2. Has overall feminine development
3. Has gynecomastia
4. Has an additional copy of Y chromosome.