Which of the following is an example of a biological macromolecule?

A spectrophotometer is an instrument that measures the intensity of light absorbed after it passes through a sample solution. With the spectrophotometer, the concentration of a chemical substance can be determined by measuring the intensity of light detected.

The parathyroid hormone (PTH) from the parathyroid glands is important in serum calcium regulation. It increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium into the bloodstream. PTH also enhances the absorption of calcium from the intestines and the kidneys.

The pH scale is logarithmic, indicating that each whole number change on the pH scale represents a tenfold change in acidity or alkalinity. Therefore, a substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4.

Most of the carbon dioxide from the blood moves into the alveoli through the process of diffusion down a concentration gradient. In the lungs, there is a higher concentration of carbon dioxide in the blood compared to the alveoli. Its molecules, therefore, move from an area of higher concentration (blood) to an area of lower concentration (alveoli) until equilibrium is reached. This is a passive process and does not require energy or carrier proteins.

a. Water boils to produce steam at 100°C - This is a phase change (from liquid to gas) and not a chemical reaction of water.

b. Water dissolves sugar - This is a physical change, not a chemical reaction of water.

c. Water produces gas with sodium metal - This reaction involves the chemical reaction of water with sodium metal to produce hydrogen gas.

d. Water and oil separate when combined - This is a physical separation, not a chemical reaction of water.

Water has a high specific heat capacity, which means it can absorb and store a large amount of heat energy without significantly changing in temperature. This helps moderate the temperature fluctuations of the air near the coast, as water can store heat during the day and release it at night, or vice versa.

Helper T cells are important cells that stimulate the action of other immune cells. For instance, they not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.

A gene is a segment of DNA that codes for a specific protein or polypeptide.

Uracil is the nucleotide that is only found in RNA. The other nucleotides are found in both DNA and RNA