Answer:
The three main similarities between prokaryotic and eukaryotic cells are as follows-
- Both the type of cells undergoes the process of respiration
- They both require energy to carry out the various processes
- They are both comprised of distinct cell membrane.
The three main differences between prokaryotic and eukaryotic cells are as follows-
- Prokaryotic cells are comprised of circular DNA, whereas eukaryotic cells are made up of linear DNA.
- Prokaryotic cells does not contain any nucleus, whereas eukaryotic cells are comprised of a well-distinct nucleus.
- Prokaryotic cells does not contain chromosomes, whereas eukaryotic cells are comprised of chromosomes.
Skin maintains homeostasis by regulating your body temperature. <span />
Answer:
d. Fluoride becomes incorporated into the crystalline structure of teeth, making them less susceptible to decay
Explanation:
Dental caries results when cariogenic (caries-causing) bacteria metabolize carbohydrates or sugars present in the mouth for their energy needs, producing organic acids as byproducts, thus lowering the pH of the plaque biofilm.
The hydroxyapatite of tooth enamel is composed mainly of phosphate ions (PO₄³⁻) and calcium ions (Ca⁺). Under normal conditions, there is a stable equilibrium between the calcium and phosphate ions in saliva and the crystalline hydroxyapatite. At low pH (acidic conditions), there is a shift in equilibrium resulting in the dissolution of hydroxyapatite from tooth enamel, a process known as demineralization. A reverse process called remineralization (the process of incorporation of minerals in tooth enamel) occurs when the saliva, acting as a buffer elevates pH. When equilibrium is shifted to favor continued demineralization, dental caries results.
However, when fluoride is present in saliva, fluorapatite, rather than hydroxyapatite, forms during the remineralization process as fluoride ions replace hydroxyl groups in the formation of the apatite crystal lattice.
Fluorapatite is less soluble than hydroxyapatite making it more resistant to demineralization, even under conditions of low pH. Thus, fluoride acts as an effective anticaries agent.
