11. www.portaldasaulas.com.br As Células Procariontes São Pobres em Membranas Cápsula Parede celular Membrana plasmática DNA do nucleóide Ribossomos Flagelo bacteriano
Figure: 03-01 Title: The plasma membrane is a fluid mosaic. Caption: The plasma membrane is a bilayer of phospholipids in which various proteins are embedded. Many proteins have carbohydrates attached to them. The wide variety of membrane proteins fall mostly into three categories: recognition proteins, receptor proteins, and transport proteins.
Figure: 04-04a Title: The nucleus. Caption: (a) The nucleus is bounded by a nuclear envelope. Inside are chromatin (DNA and associated proteins) and a nucleolus.
Figure: 04-04b Title: The nucleus. Caption: (b) An electron micrograph of a yeast cell that was frozen and broken open to reveal its internal structures. The large nucleus, with nuclear pores penetrating its nuclear envelope, is clearly visible.
Figure: 04-05 Title: Chromosomes. Caption: Chromosomes, seen here in a light micrograph of a dividing cell (on the right) in an onion root tip, are the same material (DNA and proteins) as the chromatin seen in nondividing cells adjacent to it, but in a more compact state.
Figure: 04-07 Title: Endoplasmic reticulum. Caption: There are two types of endoplasmic reticulum: rough ER, coated with ribosomes, and smooth ER, without ribosomes. Although in electron micrographs the ER looks like a series of tubes and sacs, it is actually a maze of folded sheets and interlocking channels.
Figure: 04-08 Title: The Golgi complex. Caption: The Golgi complex is a stack of flat membranous sacs. Vesicles transport material from the ER to the Golgi (and vice versa) and from the Golgi to plasma membrane, lysosomes, and vesicles. Departing vesicles bud off from the Golgi on one face; arriving vesicles join it on the opposite face.
Figure: 04-E4-2d Title: An SEM photo. Caption: (d) An SEM photo at much higher magnification, showing mitochondria, many of which are sliced open.