Answer:
Exposure to the disease
Explanation:
Before vaccines, the only way to develop immunity to a disease was to be exposed to the disease-causing pathogen without being harmed by it. A good example of this is smallpox, which was also the first vaccine developed. It was noticed that milk maids weren't catching and dying from small pox like everyone else, because they had been exposed to cowpox. This premise was used to create the first vaccine.
Vaccines give you immunity by injecting you with a small amount of a (usually inactive) pathogen. inside your body. This means your immune system produces antibodies against it. Similar to what happened with the milkmaids.
Answer:
Explanation:
Escherichia coli, is a type of bacteria that lives in the intestines. It's also found in the gut of some animals. Most of them are harmless, they aid keeping the digestive tract healthy. Though if contaminated food or fouled water is consumed, some strains can cause diarrhea .
Catalase enzymes, hydroperoxidase I (HPI) and HPII, catalyze the dismutation of hydrogen peroxide to water and oxygen but they play crucial roles in protecting cells against the effects of oxidative stress.
Some examples of pathogenic microorganisms which produces catalase include staph, bacillus, aureus,etc
Test Procedure:
- With the aid of a loop or sterile wooden stick, a small amount of bacterial colony should transferred onto the surface of clean, dry glass slide .
- A drop of 3% Hydrogen peroxide should be placed on to the slide and mixed.
- A positive result is indicated by the rapid evolution of oxygen gas (within 5-10 seconds), which is evident by bubbling, while a negative produces no bubbles or only a few scattered bubbles.
- The used slide should be disposed in the bio hazard glass disposal container.
A nonconformity exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock
Answer:
A. Molecular changes such as extracellular signals on extracellular ligands can result in quick changes in cell behaviour. One example is insulin. Upon insulin binding on the receptor on the cell membrane, the cell release GLUT4 transporters (for muscle cells) to increase uptake of glucose.
B. Slow changes in cell behaviour can be observed for other lipophilic hormones or intracellular receptors such as glucocoortoid or estrogen which reacts with receptors in the cells.
C. Insulin is required to maintain a constant blood glucose level and hence levels of insulin has to be mediated in correspondence to the blood glucose levels. Fast acting signalling is thus required for homeostasis of blood glucose levels. Where for such lipophilic hormones such as steriods, glucocortoid, these hormones tend to have a longer lasting effect and hence results in a slow change.
