The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
Primary= peptide bonds
secondary= hydrogen bond
tertiary= weak bonds, hydrophobic, disulfide bridges, salt bridges
quaternary= between polypeptides
The sudden change in climate is as a result of the interaction of the atmosphere and the lithosphere. The heavy rains at high altitude are as a result of relief rainfall. The mountain acts as a barrier, causing the air to rise. Once air rises it cools and condenses. Cloud formation often leads to precipitation on the windward side of the mountain.
Answer:
During the oxidation of glucose in the liver the malate aspartate shuttle system is used, therefore, two additional ATPs get generated at the step constituting glyceraldehyde-3-phosphate dehydrogenase.
On the other hand, in the brain, a cell uses the glycerol phosphate shuttle system, which generates two less number of ATPs. However, the remaining of the energetics for the number of ATP in both cases are similar.
Thus, the difference is based upon the kind of shuttle system used that leads to the production of 32 ATPs in liver cells and 30 ATPs in the brain cells.
