In case of starch synthesis in pea seeds [controlled by B gene], BB homozygotes produce large and round starch grains; bb homozygotes produce smaller and wrinkled starch grains and Heterozygotes produce round seeds of intermediate size. What can be inferred from this observation?
(1) The gene B mutates at a faster rate.
(2) The gene B is easily influenced by the environment
(3) Dominance is not an autonomous feature of a gene or the product that it has information for
(4) Some genes do not follow the law of segregation
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
In 1900 Mendel’s work was rediscovered by:
1. Korana, Nirenberg and Mathei
2. De Vries, Correns and von Tschermak
3. Avery, McCleod and McCarty
4. Watson, Crick and Wilkins
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 %
Thalesemia is inherited as a/an ____________ condition.
(1) Autosomal recessive
(2) Autosomal dominant
(3) Sex linked recessive
(4) Sexlinked dominant
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 sickle cell anaemia, the mutant haemoglobin molecule undergoes
(1) Polymerisation under low oxygen tension causing that changes the shape of the RBC to sickle like structure
(2) Depolymerisation under low oxygen tension causing that changes the shape of the RBC to sickle like structure
(3) Denaturation under high oxygen tension causing that changes the shape of the RBC to sickle like structure
(4) Denaturation
In Phenylketonuria,
I: | Phenylpyruvic acid and other derivatives are accumulated in brain resulting in mental retardation. |
II: | These are also excreted through urine because of its poor absorption by kidney. |
1. Only I is correct
2. Only II is correct
3. Both are correct
4. Both are incorrect