CBSE Questions for Class 12 Medical Biology Strategies For Enhancement In Food Production Quiz 11 - MCQExams.com

• Mutation breeding is the process of exposing seeds to certain chemicals and radiation in order to generate mutants with desirable traits to bred with other cultivators. This will change the base sequence of genes of crop plants. In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.
  
• Recombinant DNA technology is the process of joining DNA molecules together from 2 different species that are inserted into a host organism to produce new genetic recombinations.
• Transgenic mechanism is the mechanism of random integration of foreign DNA in transgenic animals.
• Gene therapy is a therapeutic process of delivery of nucleic acid into a patient's cell as a drug to treat a disease.

• Himgiri is a variety of wheat that is resistant to yellow rust or stripe rust.
• Pusa Sadabahar is a variety of chili resistant to leaf curl and chili mosaic virus.
• Pusa Komal is a variety of cowpea resistant to bacterial blight.
• Pusa Swarnim is a variety of brassica resistant to white rust.

Totipotency is the ability of a single cell to divide and produce all of the differentiated cells in an organism. Spores and zygotes are examples of totipotent cells. In the spectrum of cell potency, totipotency represents the cell with the greatest differentiation potential because of totipotency we can grow flower, fruit or an organism from a cell in a culture medium.

So, the correct answer is "All the above".

• Mule is the outcome of the cross made between the male donkey and female horse. 
• Donkeys and horses belong to different species, so mule is an outcome of interspecific breeding. 
• However, the mule is sterile because the chromosomes present in it do not behave as homologous and fail to make viable gametes.

• The queen bee is the only reproductive female in the beehive.
  
• Queens are developed from larvae selected by worker bees and specially fed in order to become sexually mature.
• The characteristics of the queen bee are  It devoid of wings, It has the bright red body, Head, thorax and abdominal regions are not very much distinct.
• So, the correct answer is 'Queen bee'.

$$\textbf{Correct Option A}$$

$$\textbf{Solution}$$

$$\bullet$$ $$\textbf{Option A}$$  The leghorn is a breed of chicken which is originally derived from Italy. Their main purpose is the production of good egg having white shell. So, the best layers chicken are leghorn as the produce large sized eggs

$$\bullet$$ $$\textbf{Option B}$$ The Rhode Island red is an American breed chicken which have a dual purpose of providing the best meat as well as egg.

$$\bullet$$ $$\textbf{Option C}$$  Brahma is an Asiatic breed chicken which are massive in size and their purpose is providing good meat.

$$\bullet$$ $$\textbf{Option D}$$ Kadaknath or kali masi is an Indian breed and have intense black coloration due to the deposition of melanin. They are known for high protein content.

So, the correct option is A. 

• Farmers often use the technique of 'selective breeding' in order to obtain cows that give high yields of milk. Cows that produce a lot of milk are chosen to be milked. 
• The production of milk requires that the cow is in lactation, which is a result of the cow has given birth to a calf. That means after the birth of a calf, the cow begins to lactate. 
• The lactation cycle is the period between one calving and the next. Lactation will continue for as long as the cow is milked which means production levels peak at around 40 to 60 days afterward until milking is stopped at about 10 months i.e., the production declines steadily. 
• The cow is dried off for about 60 days before calving again. Dairy farmers are familiar with the pattern of milk production. Hence, to maximize the milk production of the dairy, farmers carefully time the cow's next breeding to produce a lot of milk.  
• So, the correct answer is option A.

A.Cotton – Smooth leaved and nectar less cotton varieties do not attract bollworms

B.Sugar cane – Saccharum barberi is crossed with Saccharum officinarum, the newly formed varieity shows the desirable qualities of high yield, thick stems, high sugar and ability to grow.

C.Maize – High aspartic acid, low nitrogen and sugar content in maize leads to resistance to maize stem borers.

D.Wheat – Solid stems lead to non preference by the stem sawfly.

• In sexual reproduction, two offsprings have the same genetic material and the same body features are called identical twins.
• They are two offspring produced by the same pregnancy.
• Twins have the same genetic material and the same body features because they develop from a single fertilized egg, they have the same genome.
• So, the correct answer is 'Twins'.

• The callus is an unspecialized, unorganized, growing and dividing the mass of cells.
• It produced when explants are cultured on the appropriate solid medium, with both auxin and cytokinin in correct conditions.
  
• In Callus culture, Auxins increase root growth and cytokinins increase shoot growth.
• Hence Cytokinin increase shoot growth in callus culture.
• So, the correct answer is 'Cytokinin'.

• Inbreeding refers to the mating of more closely related individuals within the same breed for 4-6 generations.
• Continuous inbreeding reduces fertility and even productivity. This is called inbreeding depression. Hence, inbreeding depression decreases productivity.
• So, the correct answer is 'Option A'.