DNA supercoiling means under or over winding of the DNA strand and basically is to become more condensed and more organized. Supercoiling is very important as it compacts the genetic code and as if that was not enough supercoiling also regulates and oversees the access the the genetic code.
Answer:
2 molecules of ATP and 2 molecules of NADH
Explanation:
Glycolysis is the first step of cellular respiration (break down of glucose to extract energy) which occurs in the cytoplasm. Glycolysis is a pathway common to all living organisms- prokaryotes and eukaryotes, as it does not require oxygen to occur.
Glycolysis occurs in two major phases (ten steps) requiring 10 enzymes catalyzing each step; the energy-requiring phase and the energy-requiring phase.
In the energy-requiring phase, the starting molecule (glucose) gets rearranged in a series of chemical reactions, and two phosphate groups gets attached to it producing fructose-1,6-bisphosphate which is unstable, This modified sugar then splits in half due to its instability to form two different but inter-convertible phosphate-bearing three-carbon sugars (Dihydroxyacetonephosphate, DHAP and Glyceraldehyde-3-phosphate, G3P). Because the phosphates used in these steps come from 2 ATP molecules, 2 ATP molecules get used up in this phase
All the DHAP molecules get converted to G-3-P in order to enter the next phase.
In the energy-recovering phase, the 3-carbon sugar (G3P) is converted into another three-carbon molecule called pyruvate, through a series of reactions. In these reactions, two ATP and 1 NADH molecules are made. This recovery phase occurs twice (one for each of the two isomeric three-carbon sugars, DHAP and G3P). Hence, a total of 4 ATP and 2 NADH molecules are produced in this phase.
Overall, Glycolysis converts one glucose (six-carbon) molecule to two pyruvate (three-carbon) molecules and a net release of 2 ATP molecules (4 overall - 2 used) and 2 NADH molecules.
Answer:
C
Explanation:
Protozoa have been classified into three trophic categories: the photoautotrophs which harness the sun's radiant energy in the process of photosynthesis; the photoheterotrophs, which although phototrophic in energy requirements, are unable to use carbon dioxide for cell synthesis and must have organic carbon compounds