Answer:
c. The harmless bacteria had been transformed.
Explanation:
Fredrick Griffith carried out the first experiment that showed bacteria can get DNA by transformation in 1928.
He used two different strains of the bacteria Streptococcus pneumoniae a)type-III-S or smooth strain-Covered by a protective polysaccharide capsule hence lethal
b) type II-R or rough strain-Lacked the polysaccharide hence non-lethal
In his experiment he observed heat killed Type-III-S strain was not able to kill the mice. However, when its remains was added with rough strain then the blend was able to kill the mice.
When he collected blood from the dead mice it had live strains of both smooth and rough type.
He came to a conclusion that non-lethal type II-R strain was transformed into lethal type II-S strain by a "transforming principle" that was supposed to be the part of dead III-S strain bacteria.
Answer:
Las técnicas moleculares, especialmente aquellas basadas en la manipulación del material genético, permitieron automatizar el proceso de identificación y clasificación de especies
Explanation:
Las técnicas moleculares usadas para la clasificación de organismos son aquellas principalmente relacionadas a la manipulación de su material genético. En especial, las técnicas de extracción de ADN, amplificación mediante la reacción en cadena de la polimerasa (PCR) y posterior secuenciación han posibilitado automatizar el proceso de clasificación de organismos. Los marcadores moleculares de ADN basados en secuencias génicas evolutivamente conservadas tales como, por ejemplo, la secuencia del gen Citocromo Oxidasa I (COI) en animales, son ampliamente usados para automatizar este proceso de identificación y clasificación de nuevas especies.
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.
I would say c is the answer
