The earliest cells detectable in fossils were different from the cells in animals, plants, fungi, and protists living today. The
se first prokaryotic cells gave rise to eukaryotic cells approximately 1.7 billion years ago. The structure of eukaryotic cells today suggests how they might have evolved from their prokaryotic ancestors. Scientists examining mitochondria and chloroplasts now think that these organelles were probably free-living prokaryotes before becoming a part of eukaryotic cells long ago.What evidence suggests that mitochondria might have evolved before chloroplasts?
In the 1960s, Lynn Magulis came up with the theory of endosymbiosis. Different evidence supports this theory that the cell organelles like chloroplasts and mitochondria were once utilized by the independent living species. Both of these organelles exhibit their own genetic material. The mitochondria cannot differentiate to produce chloroplasts and vice versa.
However, the fact that the mitochondria are found in all the cells of eukaryotes, while the chloroplast is witnessed only in certain specific cells, shows that the evolution of mitochondria took place much earlier than the chloroplasts.
Cytology is the study of the chemistry, structure, and function of a cell. Cytology is the study of cell structure, composition, & interaction with other cells. Cytology is the medical and scientific study of cells. Cytology is the branch of biology concerned with the structure and function of plant and animal cells.
The mass of one atom of carbon in the correct number of significant figures is 1.99×10-²³. There are four significant figures each in both the atomic mass of carbon (12.01 g) and Avogadro's number, so the answer must also have 4 significant figures. The operation is shown below:
Some versions have more steps, while others may have only a few. However, they all begin with the identification of a problem or a question to be answered based on observations of the world around us.
A person can only show a recessive trait if both of their parents carried at least one copy of each of the recessive allele. The parents do not need to show the trait, as one copy is not enough to reveal it, but they must both carry it.
