Genetics And Plant Breeding - Study Mode
[#801] Consider the following events which are significant in the development of improved varieties/hybrids of plants 1. Morgan discovered genes on chromosomes. 2. Knight noted that male and female parents contributed equally to F 1 -generation. 3. Correns and de Vries rediscovered Mendel's laws of heredity. 4. Tomato carrying flavour gene is introduced. What is the correct chronological sequence of the above events?
Correct Answer
(B) 2, 3, 1 and 4
Explanation
Solution: The correct chronological sequence of the event in the development of improved varieties or hybrids of plants are as follows: 1. Knight noted that male and female parents contributed equally to the F 1 -generation. 2. Correns and de Vries rediscovered Mendel's laws of heredity. 3. Morgan discovered genes on chromosomes. 4. Tomato-carrying flavour gene is introduced.
[#802] Poliination by bats is termd as
Correct Answer
(D) Cheiropterophilly
Explanation
Solution: Poliination by bats is termd as Cheiropterophilly . The pollination of plants by bats is called chiropterophily. Plants pollinated by bats often have pale nocturnal flowers (in contrast, bees are most attracted to bright, daytime flowers). These flowers are often large and bell-shaped, and some bats have evolved specifically to reach the nectar at the bottom of them.
[#803] The phenomenon in which occurrence of one crossing over in chromosome interfers with the second crossing over in neighbouring segments is
Correct Answer
(C) Interference
Explanation
Solution: The phenomenon in which the occurrence of one crossing over in chromosome interferes with the second crossing over in neighboring segments is Interference . Interference is the term used to refer to the non-random placement of crossovers concerning each other during meiosis. One crossover "interferes with the coincident occurrence of another crossing over in the same pair of chromosomes, and I have accordingly termed this phenomenon ‘interference’."
[#804] The example of Inducible Operon is
Correct Answer
(A) Lac operon
Explanation
Solution: An example of an Inducible Operon is the Lac operon. The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria. The type of regulation that the lac operon undergoes is referred to as negative inducible, meaning that the gene is turned off by the regulatory factor (lac repressor) unless some molecule (lactose) is added.
[#805] The ratio expected from complementary gene action is
Correct Answer
(B) 9 : 7
Explanation
Solution: The ratio expected from complementary gene action is 9 : 7. Complementary genes are a type of gene interaction between two alleles (or gene versions) of two different genes that work together to create a specific phenotype or visible trait. Complementary gene action is when two different genes work together to contribute to one single trait.