Two molecules that can cross a lipid bilayer without help from membrane proteins are oxygen and carbon dioxide. The property that allows this to happen is that both oxygen and carbon dioxide molecules are nonpolar which means that they can pass easily through the hydrophobic part of the membrane. The lipid bilayer is present in all cell membranes. It consists of two layers of the fat cells which are arranged into two sheets. It functions as a barrier which marks the boundaries of the cell. The inner part of a lipid bilayer is nonpolar since it is composed of the hydrophobic end of the phospholopids.
Answer:
C. Gas exchange occurs through the placenta.
Explanation:
The fetus is a developing baby in the womb or uterus. The fetus is incapable of performing certain life processes itself and hence, depends on the mother to do them. One of these processes is GAS EXCHANGE. Gas exchange occurs in the fetus via a structure called PLACENTA.
Placenta is a structure that forms in the uterus during pregnancy. It helps the developing fetus supply oxygen and nutrients from the mother and also remove wastes from the fetus back to the mother. The oxygen is taken into the fetus via the PLACENTA while the carbon dioxide (waste product of respiration) is removed via the PLACENTA. Hence, Gas exchange occurs through the placenta.
Answer:
Japan, China, the U.S., Indonesia, Chinese Taipei and South Korea have been named by Pew Charitable Trusts on a “shame list” of countries responsible for overfishing tuna in the Pacific. According to Pew, the “Pacific 6” are responsible for 80 percent — 111,482 metric tons in 2011 — of the annual catch of bigeye tuna.
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Take the atomic mass of silicon and put it over one. Then set that equal to x over 4.8 x 1026. X will equal to the weight of silicon in grams.
26. a megagram = 10⁶ grams while a kilogram = 10³ grams, so the megagram is bigger
28. a mililiter = 10⁻³ liters while a microliter = 10⁻⁶ liters, so the mililiter is bigger
36. 1 meter is equal to 100 centimeters, so the decimal moves right 2 places
37. 1 micrometer is equal to 0.001 milimeters, so the decimal moves left 3 places
38. 1 centimeter is equal to 0.00001 kilometers, so the decimal moves left 5 places
39. 1 micrometer is equal to 10⁻¹² megameters, so the decimal moves left 12 places
40. 1 kilometer is equal to 100000 centimeters, so the decimal moves right 5 places
