a cell is the smallest structural and functional unit of an organism
Answer:
Mitochondria and chloroplasts
Explanation:
These two organelles support the theory in that both have 70S ribosomes, the presence of a circular DNA within, and similar size. They can undergo division within the eukaryotic cyptoplasm. Both of these organelles are surrounded by a double membrane, which in the case of chloroplast is known to originate from ancient bacteria that lost its peptidoglycan component. Mitochondria and chloroplast both evolved from ancient free living bacteria that entered into larger cells, which in the case of mitochondria is known to be archaea and in the case of chloroplast is a eukaryotic cell. With this, these cells became dependent on it in a manner that it could not exist without it.
<h3>Hope this helps!</h3>
Answer:
Facilitated diffusion involves transport protein
Explanation:
Answer:
Explanation:
Cell specialization is also called cell differentiation. Through this process, specialized cells form from the unspecialized cells. Then many cells are formed and determined to form specialized functions.
The stem cells are the unspecialized cells which form a different kind of specialized cells.
The muscle cells, nerve cells, sperm cells, red blood cells are specialized cells perform different specialized functions. All these cells arise from stem cells. The nerve cells receive impulse, muscle cells can contract, etc.
There are certain inductive signaling genes that send the signal to the differentiated cells. These signaling molecules are called ligands. These ligands move to another cell to produce specialized cells. In other words, there are some transcription factors and genes responsible for such cell differentiation and the formation of specialized cells.
Another example is zygote, which is an unspecialized cell. This is also a totipotent cell that has the potentiality to reproduce different cells.
Answer:
Option (a) and (d).
Explanation:
The breaks in DNA molecule may occur due to replication error and oxidizing agent. The double-stranded breaks in DNA can be corrected by Homologous end joining and non homologous end joining.
Homologous end joining is used to repair the DNA present in G2 nad S phases of the cell cycle. The homologous sequences of DNA is used to repair the DNA. Non homologous end joining occurs in the cell present at G0 and G1 phase of the cell cycle. The DNA broken ends are juxtaposed and later rejoin together by DNA ligase.
Thus, the correct answer is option (a) and (d).
