Answer:
true
Explanation:
because it can catch heat waves and other things
Answer: By definition, if the atomic number =
7
, then there are 7 protons, 7 electrons, and 8 neutrons!
Explanation:
The atomic number is by definition the number of protons, positively charged particles, contained within the atomic nucleus. So if there are 7 protons, there MUST be 7 electrons, 7 negatively charged particles. Why? Because matter is electrically neutral, and positive and negative particles must be equal.
Electrons have negligible mass; the mass number depends on the number of protons contained within the nucleus, PLUS the number of neutrons. Given that we have 15 N
, there must be 8 neutrons contained within the nucleus. does this help?
Answer:
E) Improve membrane fluidity
Explanation:
Cholesterol constitutes the basic structural element of the skeleton of cell membranes. Without their reinforcement, the membranes would become extremely fluid and lose their consistency. Cholesterol is found in the esterified membranes in its hydroxyl group (OH): with fatty acids, mainly oleic and linoleic, or as cholesterol sulfate. The cholesterol-sulfate polar group is disposed on one of the faces of the membrane that interacts with other polar groups in that area, while its bulky hydrophobic portion is embedded between the apolar parts of the lipids that form the membrane skeleton and They fulfill many other functions, among which the reduction in the permeability of protons and sodium ions, and their participation in signal transmission. Cholesterol is also essential in phagocytosis processes carried out by cells to capture many nutrients and, in general, for the function of cleaning up organic waste produced by macrophages.
The membranes must have a fluid structure so that the integrated proteins can move "horizontally" to interact with their ligands and with other proteins. The fluidity is given by unsaturated fat. With the excess of saturated fat, the membranes become rigid, but only with the necessary unsaturated fat the membranes are extremely fluid and very sensitive to temperature changes. Cholesterol stabilizes the structure of the membranes; In order for them to have the correct structure, they must have the correct proportions of saturated, unsaturated fats and cholesterol. The membranes produced in the laboratory without cholesterol are unstable to temperature changes, drastically modifying their fluidity against the small temperature changes that occur in the physiological range.
In addition to its functions in cell membranes, cholesterol is an important product that metabolism uses as a raw material to make other compounds:
*Bile salts
*Sex hormones
*Hormones of the adrenal cortex (corticosteroids)
*Vitamin D (Calciferol)
