Para establecer la relación entre antígenos y anticuerpos podemos tomar como ejemplo los grupos sanguíneos. Contesta F o V y justifica las falsas. 1-Los sistemas ABO y Rh están determinados genéticamente y se basan en respuesta asntígeno-anticuerpo.

2- En el sistema ABO la presencia o ausencia de los antígenos A y B en la superficie de los glóbulos rojos determina el grupo sanguíneo.

3- Los individuos cuyos glóbulos rojos poseen antígenos Rh se clasifican como Rh positivos mientras que los que carecen de antígenos Rh se clasifican como negativos.

4- La eritroblastosis fetal puede producirse cuando una madre Rh negativo está embarazada con un feto Rh positivo.

5- Antes de una transfusión se determina el grupo sanguíneo del dador y del receptor buscando compatibilidad.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein

It explains why rocks appear in layers