When the food you have eaten reaches the stomach, the hormone released is what we call Gastrin. The ‘G’ cells produce these hormones. These hormones are produced in the lining of the stomach and upper small intestine. When a person is having a meal, it is the gastrin which stimulates the stomach to release gastric acid. Aside from the proteins from the food that are broken down, the gastrin makes it possible for the vitamins to be absorbed by the stomach. Gastrin also serves as a disinfectant and kills most of the bacteria that enter the stomach with food, minimising the risk of infection within the gut. It also stimulates the stomach lining’s growth as well as it also increases muscle contractions of the gut to aid digestion. On the other hand, the gastrointestinal hormones or the gut hormones constitute a group of hormones secreted by enteroendocrine cells in the stomach, pancreas, and small intestine that control various functions of the digestive organs.
Answer:
Answer No 1:
The earliest evidence for the occurrence of viruses was the discovery of an infectious agent in the sap of a tobacco plant. Experiments were set with different filters from which bacteria could pass but viruses being even smaller than bacteria could not pass.
Viruses were difficult to study because they are very small and couldn't be seen even under a microscope.
Answer No 2:
Wendell Stanley made his studies on the tobacco mosaic virus (TMV). Wendell Stanley developed techniques and crystallized this virus. At that time, it was known that even a very simple cell does not undergo crytallization. Hence, Wendell Stanley got to known that this structure is some infectious agent which has the ability of crystallization.
Answer No 3:
The four forms of viral genomes are:
- double-stranded DNA
- single-stranded DNA
- double-stranded RNA
- single-stranded RNA.
Answer No 4:
The capsid can be described as proteins which make up a shell to enclose the genome of a virus. Capsomeres can be described as the protein sub-units from which a capsid is made. The shapes of a capsid can be characterized into
- rod-shaped: helical viruses, or inside spherical viruses
.
- icosohedral: icosohedral viruses or the heads of bacteriophages.
Answer No 5:
The components of a viral envelope involve phospholipids and membrane proteins and proteins and glycoproteins. The phospholipids and membrane proteins are derived from the host cell. The proteins and glycoproteins are of the viral origin.
Answer: Mendel would have concluded that one pair of factors (genes) is responsible for two different characters in plants.
Explanation:
The 9:3:3:1 ratio observed by Mendel helped him to form his <em>Law of Independent Assortment </em>which states that the inheritance of one pair of factors (genes) is independent of the inheritance of the other pair.
Also from his previous studies, he obtained a 3:1 ratio for a single gene expression, flower color, which enabled to form <em> the Law of Segregation</em>, which states individuals possess two alleles and a parent passes only one allele to his/her offspring.
However, if he had observed a 3:1 ratio for two traits, he would have concluded that inheritance of characters occurs in pairs i.e., that a pair of alleles is responsible for two different characters in plants.
Answer AND Explanation:
NORMAL CELLS CANCEROUS CELLS
- Undergo apoptosis Evade apoptosis
- Controlled cell division Uncontrolled cell division and self sufficiency in growth signals
- Sensitive to growth signals Insensitivity to antigrowth signals
- They do not form other blood vessels Sustained angiogenesis
- They are non-metastatic Invade local tissue and spread to distant sites
Answer:
Gel electrophoresis is a technique used to separate DNA fragments according to their size. ... DNA fragments are negatively charged, so they move towards the positive electrode. Because all DNA fragments have the same amount of charge per mass, small fragments move through the gel faster than large ones.
Explanation: