In most hypotheses of early Earth and the formation of life, it is accepted that the atmosphere was a reducing one. This means t
hat there was an abundance of methane, ammonia, and water vapor, but there was an absence of significant amounts of oxygen gas. Based on this assumption, what was likely the first metabolic activity to harness ATP to evolve in primitive cells? A) Photosynthesis, as plants evolved before animals
B) Cellular respiration, as this generates the most ATP
C) Glycolysis, as this does not require organelles not oxygen
D) Calvin cycle, as glucose was required by all cells for metabolism
It is believed that glycolysis – the first phase of cellular respiration in eukaryotic cells- is considered an ancient biochemical process that early organisms utilized to tap the energy required for cell functions. This is because the process does not require oxygen – because early conditions on earth were anoxic before the great oxygenation event. It is after the great oxygenation event that the Krebs cycle evolved.
The actual answer (sorry for the late reply, but this is for the rest of the people coming afterwards) would actually be B) Switch primitive reptile with primitive insect. Insects came before any reptiles.
C: disease symptoms with varying severity based on genetic background
Explanation:
The chromosomes are composed of two under normal conditions but a genetic disorder in which a person has three copies of a chromosome instead of two is trisomy of the chromosomes and it will definitely lead to a disease syndromes.
I think that because since it doesn't have a nucleus or as many organelles as eukaryotic.They are smaller in size and don't have membrane bound structures.
