1.
Kary Mullis was an American biochemist who won the Nobel Prize in Chemistry in 1993 for his invention of the polymerase chain reaction technique (PCR). PCR allows for rapid amplification of DNA sequences which are important in many medical diagnostics to identify disorders, bacteria and viruses. For example, in the COVID-19 pandemic, PCR plays an essential role in helping to detect if a person carries the coronavirus. To amplify the DNA sequences using PCR, RNA primers are required. When designing RNA primers for PCR, one must take note to avoid the possibility of formation of hairpin loops of the RNA primers. Hairpin loops are formed when the bases in the RNA primer sequences are complementary and bind with itself, forming a hairpin-shaped loop
4.
The diagram below represents light-dependent (on the left) and light-independent on the right) reactions of the photosynthesis:
The plant was not receiving the sun rays for 3 days. Do light-independent reactions still occur in that
plant and why?Deselect Answer
5.
Greenhouse effect is the natural process that warms the Earth’s surface. Sun rays reach the surface and reflect. Some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. The absorbed energy warms the atmosphere and the surface of the Earth.
In the last three centuries, the amount of greenhouse gasses in the atmosphere dramatically
increased, which led to the increasing average temperature on the Earth and melting glaciers. The
diagram below represents the changes of the amount of greenhouse gasses with a pass of time:
Which factor mostly affected the greenhouse effect situation in the 21
st century?Deselect Answer
