Answer:
1. They must be removed before sister chromatids or homologous chromosomes can separate
Explanation:
During the S-phase of the cell cycle, not only does DNA have to be replicated, but also newly synthesized DNA molecules have to be connected with each other. This replicated DNA (sister chromatids) remain physically connected with each other from S phase until metaphase. This physical connection is called Sister chromatids cohesion.
Sister chromatid cohesion depends on COHESIN, a tripartite protein complex that forms a ring structure to hold sister chromatids together during mitosis and meiosis. Cohesin regulates the separation of sister chromatids during cell division, either mitosis or meiosis. This sister chromatid cohesion is essential for the biorientation of chromosomes on the mitotic or meiotic metaphase spindle, and is thus an essential prerequisite for chromosome segregation. Without the cohesion, sister chromatids would not be segregated symmetrically between the forming daughter cells, resulting in aneuploidy.
Cohesion is established during S-phase of DNA replication, and the cohesins hold the sister chromatid together after DNA replication until anaphase when the removal of cohesin leads to separation of sister chromatids (meiosis II and mitosis) and homologous chromosomes (meiosis I).
The rapid leaf movements resulting from a response to touch (thigmotropism) primarily involve<u> potassium channels.</u>
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- Thigmotropism is a directional growth movement that develops in response to a touch stimulation through the mechanosensory system.
- Plant biologists have also discovered thigmotropic reactions in blooming plants and fungus, while thigmotropism is often found in twining plants and tendrils.
- A directed growth movement known as thigmotropism happens in response to touch. Typically, twining plants and tendrils that coil around supports exhibit thigmotropism.
- The trigger for the geotropism process is gravity. A plant organ's directional response to physical contact or touch with a solid object is known as thigmotropism.
- The induction of some pattern of differential growth typically results in this directional reaction.
- The climbing tendrils of some plants, such the clinging fern, provide a clear illustration of this phenomena.
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Answer:
Neuroregeneration is the process by which individuals regain neurological function following an injury to the nervous system
Explanation:
The body cell repairs or regenerates by the process of Neuroregeneration. The process allows formation of new neuron cells. The neuroregeneration process is different in PNS and CNS. During accidents, falls or assaults, this process starts generating new cells (neurons) and repairing of tissues present in the nervous system. The PNS composed of spinal and cranial nerves. The CNS composed of spinal cord and brain.
<span>Answer: 16 combinations
A fruit fly has four pairs of chromosomes in its cells. Assuming all pair is heterozygotes, each pair of the chromosome can be divided into two possible combinations. So, if there are 4 pairs then the possible combination would be 2 * 2 * 2 * 2= 16 possible combinations.</span>
