Quim

Cell size and scale
http://learn.genetics.utah.edu/content/begin/cells/scale/

CAP. 2 QUIMICA DE LA VIDA
The relative scale of biological molecules and structures Cells can vary between 1micrometer ( m) and hundreds of micrometers in diameter. Within a cell, a DNA double helix is approximately 10 nanometers (nm) wide, whereas the cellular organelle called a nucleus that encloses this DNAcan be approximately 1000 times bigger (about 10 m). See how cells compare along a relative scale axis with other molecules, tissues, and biological structures (blue arrow at bottom). Note that amicrometer ( m) is also known as a micron. http://www.nature.com/scitable/topicpage/what © 2010 Nature Education All rights reserved.

-is-a-cell-14023083

Molecular Art | Molecular Science Home ofDavid S. Goodsell

Composición química de organismos vivos

The composition of a bacterial cell Most of a cell is water (70%). The remaining 30% contains varying proportions of structural andfunctional molecules. © 2010 Nature Education

http://mgl.scripps.edu/people/goodsell/

http://www.nature.com/scitable/topicpage/ what-is-a-cell-14023083

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ARBON

YDROGEN

XYGEN

ITROGENODIUM

OTASIUM

H2O

2

Electronegatividad

Enlace covalente NO polar

Enlace covalente polar

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3

Electrones se transfieren

Electrones se comparten equitativamenteY+ XEnlace iónico Ejemplos: NaCl

+Y X -

XX
Enlace covalente NO polar H2, CH4

Enlace covalente polar H2O

Enlace iónico

4

Puentes de H entre moléculas de agua

5

Agua es elsolvente más abundante y versátil que existe.

PROPIEDADES EMERGENTES DEL AGUA
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¿Por qué algunas sustancias son solubles en agua y otras no?

(a) Lysozyme molecule in a nonaqueous environment(b) Lysozyme molecule (purple) in an aqueous (c) Ionic and polar regions environment on the protein s surface attract water molecules.

Lisozima

proteína soluble en agua

6

Sustancias...