Answer:
Agua
Explanation:
El agua costituye aproximadamente 3/4 partes de la tierra, 70% del cuerpo humano esta constituido por agua, y aproximadamente el 90% de las células contiene agua. Esta sustancia es la mas importante para el funcionamiento de nuestro organismo y para alcanzar un equilibrio. Todos los seres vivos dependen del agua para sobrevivir, desempeñando un rol único y central en el funcionamiento de los sistemas vivos.
El agua cumple diversas funciones en el organismo, entre ellas, como las mencionadas en el problema, se encuentra:
- Regula la temperatura del cuerpo. Dependiendo de la temperatura ambiental, las moleculas de agua permiten que el cuerpo mantenga la temperatura si el ambiente esta frio, y emane calor si la tempeartura ambiental es elevada.
- Convierte los alimentos en energía. Cumple un rol principal en la descomposición bioquímica de alimentos.
- Ayuda a llevar nutrientes y oxígeno a las células. Una vez extraidos los nutrientes, se convierte en el medio por el cuál estos últimos pueden transportarse hasta alcanzar las celulas de destino final.
- Conforma el 83% de la sangre. Como se mencionó previamente consituye la mayor parte de la sangre. Solo el plasma sanguineo esta constituido por el 90% de agua.
Answer:
D) secrete a cytokine that triggers apoptosis
Explanation:
Cytotoxic T cells also known as killer cells are lymphocytes that can kill foreign cells (also cancer cells, damaged and infected cells). They express specific type of receptors called T-cell receptors (TCRs) which recognize antigen of foreign cells. Cytotoxic T cells release cytotoxins such as perforin and granzymes and their role is to trigger the signal cascade in the target cell that will lead to apopotsis.
Answer:
Amoeba;
Explanation:
Amoeba:
Amoeba will contain nucleus (contain the genetic information). Nucleus normally appears as dense circular mass under microscope.
Organelles are present. Organelles appears like distinct masses that are rounded in shape and smaller than nucleus.
Plasma membrane is present.
Bacteria;
Nucleus will be absent in bacteria. The nucleoid normally appear lighter in color under microscope.
Ribosomes will be present. Ribosomes appears like black dots within the cytoplasm.
No plasma membrane will be present.
Answer:
d. Genes that play a role in the same metabolic pathway are organized into an operon.
Explanation:
In prokaryotic organisms like bacteria, polycistronic mRNAs exist which means that each gene does not have a separate promoter of its own. In fact many genes are under the control of a single promoter. These genes being a part of same metabolic pathway are organized into an operon. For example, lac operon and tryptophan operon. In lac operon, three genes named as β-galactosidase, permease and transacetylase are expressed under a single promoter which is known as lac promoter.
In contrast to this, in eukaryotes the mRNAs are monocistronic i.e. only a single gene is controlled under a single promoter.