Answer:
Because DNA polymerase can synthesize DNA strands in 5' to 3' direction only.
Explanation:
The 5' end of one DNA strand is present opposite to the 3' end of the other strand. But DNA polymerase enzyme can elongate the primers in 5' to 3' direction only. Formation of a phosphodiester bond between the existing nucleotide and the incoming nucleotide requires the free 3'OH. This 3' OH serves in the nucleophilic attack during the formation of the bond.
Therefore, the lagging strand is synthesized discontinuously in the form of short DNA fragments. These are called Okazaki fragments. Primers are formed for short distances which in turn are elongated by DNA polymerase to form the Okazaki fragments. On the other hand, the synthesis of the leading strand occurs continuously in the same direction in which the replication fork moves.
Catastrophism is the theory that the Earth has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope.[1] This is in contrast to uniformitarianism (sometimes described as gradualism), in which slow incremental changes, such as erosion, created all the Earth's geological features. The proponents of uniformitarianism held that the present was the key to the past, and that all geological processes (such as erosion) throughout the past were like those that can be observed now. Since the early disputes, a more inclusive and integrated view of geologic events has developed, in which the scientific consensus accepts that there were some catastrophic events in the geologic past, but these were explicable as extreme examples of natural processes which can occur.
Answer:
C. a decrease in phospholipid fatty acid side chain length and a decrease in side chain saturation
Explanation:
Temperature is a factor that has a huge impact on cell membrane structure, more precisely its fluidity. So, for example, if temperature increases, the cell membrane becomes more fluid because the fatty acid tails of the phospholipids become less rigid.
Answer:
uniformitarianism, Fossil groups, 48 million years ago.
Explanation:
- Uniformitarianism is the doctrine of uniformity that assumes that same environmental laws and process operate till date that has also occurred on the past but not with the same uniformity. Unlike the atmospheric that is short-lived and sudden changes over the period of time.
- William Smith was a geologist who has noticed a certain type of fossil in a certain layer of sedimentary and igneous rock. A similar layer of strata could be found in the areas that were further apart.
- The Permian period was from 229 to 251 million years and was the last period of the paleozoic era and is recorded for the last major extinction in the history of life in earth and it lasted for 48 million years.
