Genetics And Plant Breeding - Study Mode

[#571] Match the following columns: Column I (Scientist) Column II (Discovery) a. Shull 1. DNA model b. Waldeyer 2. First hybrid c. Fairchild 3. Heterosis d. Watson and Crick 4. Chromosome
Correct Answer

(B) a-3, b-4, c-2, d-1

Explanation

Solution: a. Shull discovered Heterosis. He described heterosis in maize in 1908 (the term heterosis was coined by Shull in 1914. Heterosis refers to the phenomenon that progeny of diverse varieties of a species or crosses between species exhibit greater biomass, speed of development, and fertility than both parents. b. Waldeyer discovered chromosomes. He coined 1888 the term "chromosome" to describe them. Chromosomes are threadlike structures made of protein and a single molecule of DNA that serve to carry the genomic information from cell to cell. c. Fairchild discovered the First hybrid. In 1716 - 17 he was the first person to scientifically produce an artificial hybrid, Dianthus Caryophyllus barbatus , known as "Fairchild's Mule", a cross between a Sweet William ( Dianthus barbatus ) and a Carnation pink. d. Watson and Crick have given a DNA model. The discovery in 1953 of the double helix, the twisted-ladder structure of deoxyribonucleic acid (DNA), by James Watson and Francis Crick marked a milestone in the history of science and gave rise to modern molecular biology.

[#572] The stamens are united throughout the whole length by both the filaments and the anthers, the condition of stamen is known as
Correct Answer

(B) Synandrous stamens

Explanation

Solution: The stamens are united throughout the whole length by both the filaments and the anthers, the condition of stamen is known as Synandrous stamens. Synandrous means Having stamen fused along both their filaments and anthers, Having stamens fused in any way.

[#573] Disc or indent cylinder separator separates the seeds on the basis of
Correct Answer

(B) Length

Explanation

Solution: A disc or indent cylinder separator separates the seeds based on Length. Indents use a combination of pocket size, centrifugal force, friction, and gravity to make separations possible. This instrument helps to separate seeds according to their length. The equipment consists of a slightly inclined horizontal rotating cylinder and a movable separating trough. The inside surface has small closely spaced hemispherical indentations. Small seeds are pressed into the indents by centrifugal force and can be removed. The larger seeds flow in the centre of the cylinder and are discharged by gravity.

[#574] The most abundant RNA in cell is
Correct Answer

(C) rRNA

Explanation

Solution: The most abundant RNA in a cell is rRNA. Ribosomal RNA (rRNA) is the most common form of RNA found in cells - it makes up around 50% of the structure of the ribosomes. It is produced in the nucleus, before moving out into the cytoplasm to bind with proteins and form a ribosome. Transfer RNA (tRNA) is found in the cytoplasm and has a complex shape.

[#575] One Gene-one polypeptide was given by
Correct Answer

(D) Beadle

Explanation

Solution: One Gene-one polypeptide was given by Beadle. The theory is that each gene is responsible for the synthesis of a single polypeptide. It was originally stated as the one gene-one enzyme hypothesis by the US geneticist George Beadle in 1945 but later modified when it was realized that genes also encoded non-enzyme proteins and individual polypeptide chains. It means that some genes accounted for single polypeptide chains of a protein comprised of multiple chains. The phenomena led scientists to conclude that genes specify protein products.