Answer:
B. Glucagon
Explanation:
Glucagon is a pancreatic hormone, secreted by the alpha cells of islets of Langerhans. Whenever the blood glucose level falls, glucagon is released to increase the blood glucose levels. This function of glucagon is quite opposite to the function of insulin and hence both are antagonistic hormones. Insulin reduces the blood glucose where as glucagon increases the blood glucose.
Glucoagon is large polypeptide of 29 amino acids. Since it helps in increasing the blood glucose homeostatic levels it is called as hyperglycemic hormone. It does so by stimulating certain processes such as:
- Stimulating Glycogenolysis i.e breakdown of glycogen to release more glucose from liver.
- Stimulating Gluconeogenesis i.e. synthesis of glucose from non-carbohydrate sources like proteins.
- Glucagon inhibits the process of glycogenesis i.e. synthesis of glycogen, the storage form of glucose.
Answer:
Selection is a directional process that leads to an increase or a decrease in the frequency of genes or genotypes. Selection is the process that increases the frequencies of plant resistance alleles in natural ecosystems through coevolution, and it is the process that increases the frequencies of virulence alleles in agricultural ecosystems during boom and bust cycles.
Selection occurs in response to a specific environmental factor. It is a central topic of population and evolutionary biology. The consequence of natural selection on the genetic structure and evolution of organisms is complicated. Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection). It can increase the genetic variation in populations by selecting for or against several genes or gene combinations (leading to disruptive selection or balancing selection). Natural selection might lead to speciation through the accumulation of adaptive genetic differences among reproductively isolated populations. Selection can also prevent speciation by homogenizing the population genetic structure across all locations.
Selection in plant pathology is mainly considered in the framework of gene-for-gene coevolution. Plant pathologists often think in terms of Van der Plank and his concept of "stabilizing selection" that would operate against pathogen strains with unnecessary virulence. As we will see shortly, Van der Plank used the wrong term, as he was actually referring to directional selection against unneeded virulence alleles.
Answer:
Lack of oxygen
Explanation:
There are two mechanisms for energy production (glucose breakdown), aerobic and anaerobic. When adequate amounts of oxygen are present, aerobic mechanism is used. However, when there is insufficient oxygen, such as during exercise, the anaerobic mechanism is used.
Answer:
Gene, a part of DNA that determines the trait of individual characteristics
Explanation:
1.Aa
2.aa
3. Aa
4.aa
50% Aa and 50%aa
