Answer:
C: Lipid A
Explanation:
Lipid A is a component of the endotoxin (also called the lipopolysaccharide) present in Gram-negative bacteria. The LPS has 3 component namely;
- the O-antigen: they are antigenic determinants and are the outer carbohydrate chains
- the core polysaccharide: forms the centre core of the LPS
- The Lipid A: forms the innermost part of the LPS and triggers acute inflammatory responses (e.g endotoxic shock) when released.
Upon detection of an endotoxin which forms the component of the outer membrane of a Gram negative organism (in exception to the Gram-positive bacteria called <em>Listeria monocytogenes</em>), the innate immune defense system (e.g macrophages and T-helper cells) are alerted to initiate elimination strategies towards the invading organism. Lipid A binds to the CD14/MD2 receptor on macrophages and monocytes which activates the nuclear factor kappa- light chain enhancer (NF-κβ). The activation of NF-κβ protein triggers the production of inflammatory cytokines which includes Interleukin-1 (IL-1), IL-12, IL-18 as well as the Tumor necrosis factor- alpha (TNF-α).
Inflammatory responses are as a result of the release of these cytokines which sometimes leads to shock and death of the host
Answer:
Answer is bile
Cholecystokinin is secreted by cells of the upper small intestine. Its secretion is stimulated by the introduction of hydrochloric acid, amino acids, or fatty acids into the stomach or duodenum. Cholecystokinin stimulates the gallbladder to contract and release stored bile into the intestine.
Answer:
Week 20
Explanation:
It would affect most in the first 12 weeks.
Primary production within the open ocean is mainly through diatoms which are single-celled photosynthesising organisms. Although the concentration of productivity in the open ocean is relatively low, the vast area of the ocean means that this form of productivity contributes greatly to overall primary production on Earth. There are also regions of relatively high production from diatoms in certain parts of the ocean. This is because the productivity of diatoms is limited by a lack of certain essential nutrients in the ocean, such as iron and silica, which tend to sink to greater depths in the ocean than the surface layers that the diatoms inhabit. In these regions, upwelling occurs, bringing nutrients from the deep ocean to the surface, and resulting in diatom blooms. This occurs typically on the west coasts of continents, because upwelling occurs here due to something called the Bernoulli Effect, which relates the the way the Earth spins. This is why very productive fishery areas are usually found on the west coasts of continents, at least in the Southern Hemisphere, and why the seawater is cold in these regions.