The purple spots on the colorless background of corn kernels observed by Barbara McClintock were the result of the transposition of the Ds elements out of the color gene.
<h3>What are the genetic elements found in corn?</h3>
- A transposable element is removed from one spot in the DNA and inserted into a different site in the DNA during the process of genetic transposition, which allows genes to shift their location on chromosomes.
- The first recognized genetic instability was caused by genetic transposition.
- The size of the tissue patch displaying the reversion phenotype increases as a reversion event happens earlier in the kernel development.
- Barbara McClintock saw purple dots on maize kernels with an otherwise colorless background.
- These spots were caused by the Ds components of the color gene being transposed.
- The wild-type (purple) phenotype manifests itself in cells where Ds from the color gene "C" sequence has been lost.
Hence, Barbara McClintock discovered purple patches on the colorless backdrop of maize kernels due to the transposition of the Ds elements out of the color gene.
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Answer:
Number of bacteria cells = 2621440 cells
Explanation:
The generation time of a bacteria specie is the time it takes for a population of bacteria to double in number. The generation time for most common bacteria is quite short, about 20 minutes to 1 hour.
Bacteria reproduce asexually by binary fission, in which the parent cell divides into two to produce two identical daughter cells.
In the given question, the generation time of the bacterial species is 20 minutes.
The time that have passed from between the time the sandwich was packed at 6:00 am to lunch time by 12:00 pm is 6 hours.
Using the given formula in the hint: number of cells = 2^(ab) × C
Where a = number of times per hour the bacteria reproduces; b = number of hours; C = number of bacteria at the start
a = 60 minutes/ 20 minutes = 3; b = 6; C = 10
Number of cells = 2^(3 × 6) × 10
Number of cells = 2621440 cells
The nucleus is a large(in relation to the other organelles), black shape so it is easily distinguishable and unlike anything else
Oil spills into rivers, bays, and the ocean most often are caused by accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities. Spills can be caused by: people making mistakes or being careless.
<span>The phase of mitosis during which the nuclear envelope fragments and the nucleoli disappear is called
PROPHASE.
In prophase, the nuclear envelope breaks down, the chromosomes become visible and condense, followed by which spindle fibers form.</span>