lunes, 20 de mayo de 2019

Steven Spielberg

To many, Steven Spielberg is the most successful filmmaker of all times. Born on December 18, 1947, he grew up with his parents and three sisters in Ohio and other North American states.

As a child, he was never interested in his studies. His true interest was in filmmaking and he used his family video camera to record all kinds of scenes and make amateur films. He sometimes showed them in his home and charged admission. His sisters sold popcorn. He was a child of great imagination and he liked to impress his younger sisters using special effects and props he created

Spielberg made his first film when he was 12 years old. When he was 16, he made a two-hour sciences fiction film about an encounter with aliens. His father rented a local cinema to show the film and in one night he got back the $500 he had spent making it.

He applied to film school twice but he was not admitted because his secondary school grades were not high enough. He decided to get a job at Universal Studios and began his career working there, where he directed several films and TV series. His first big hit was Jaws (1975), a horror film about a huge killer shark. It made him a multi-millionaire, and after that Spielberg could do whatever he wanted. Then came such great films as Close Encounters of the Third Kind (1977), the Indiana Jones trilogy (1981-1989, with a fourth part in 2008), E.T.: The Extraterrestrial (1982), Schindler's List (1993), Jurassic Park (1993) and its sequel (1997) and War Horse (2011).

Today Spielberg is a billionaire, but he is still a modest, private person. He enjoys a happy family life with his second wife, Cate Capshaw, the three children they had together, the two children they adopted, and the two children they have from their previous marriages.

martes, 7 de mayo de 2019

Clases de mutaciones

Las mutaciones son cambios o alteraciones en la información genética de un organismo, que tiene influencia en sus características y se pueden transmitir a la descendencia.

Las mutaciones pueden ser cromosómicas o genéticas.


La mutación por sustitución 


Es el reemplazo de una base nitrogenada por otra, por lo que únicamente se cambia la información del codón que contiene a esa base.


La mutación por inserción


En un punto de la secuencia de bases, se inserta una base incorrecta, lo que determina un "corrimiento hacia atrás" del resto de las bases nitrogenadas; es decir, se cambian todos los codones a partir del lugar de la inserción.


La mutación por deleción


Ocurre cuando en un punto de la secuencia de bases, se elimina una base, lo que produce un "corrimiento hacia delante" del resto de las bases nitrogenadas. Se modifican todos los codones a partir del sitio de la deleción.


CONSECUENCIAS DE LAS MUTACIONES:



Las mutaciones sin sentido producen que un codón de la secuencia se convierta en uno de término y la proteína sea más corta de lo que realmente debería ser, afectando su funcionamiento


Las mutaciones silentes: en ellas, se sustituye una base por otra que codifica para el mismo aminoácido. No hay efectos en la proteína.


Las mutaciones de sentido erróneo, donde la mutación produce que uno más codones codifican para aminoácidos distintos de los normales.


Más información:

https://bit.ly/2Lclju7




Fuente: 

Schneider, Fernando; “Biología. Respuesta al medio. Regulación e Integración de Funciones. Del ADN al organismo” Ed. SM Serie Proyecto Nodos; 2014.