Chap 7

Nuclear Pore Complex:

Each nuclear pore consists of up to 50 proteins, Note that nuclear pore (gate) extends through both inner and outer nuclear membranes— so inside of nucleus is connected with cytosol

nuclear lamina

Fibrous proteins that form a lattice, provides structure and shape.

The Nucleus

Function: Information storage and processing Contains the cell's chromosomes, = digital code - Ribosomal RNA synthesis (in the nucleolus) Structure: The nucleus is surrounded by a double-membrane nuclear envelope. - The nucleus has a distinct region called the nucleolus (site of ribosome/RNA assembly).

The most numerous intracellular structure is....

Ribosomes, the site of protein synthesis in all living organisms.

Ribosomes

Structure: Non membranous (not considered organelles) have large and small subunits containing both Rna molecules and Proteins can be attached to the Rough ER or the cytosol (fluid part of the cytoplasm) Function: Protein synthesis

Golgi Apparatus

Structure: formed by a series of stacked flat membranous sacs called cisternae function: the golgi process, sort and ships proteins syntehisied in the RER, membranous vesicles carry materials to and from the organelle

Smooth Endoplasmic Reticulum

Structure: network of membrane bound tubes and sacs function: Enzymes in the smooth ER synthesize Fatty acids and phospholipds or break down poisinous lipids, reservoir for Ca2+

The Nuclear Envelope

The nuclear envelope has two membranes, each consisting of a lipid bilayer, and is continuous with the endoplasmic reticulum.

4 major differences between Eukaryotes and Prokaryotes

membrane- (1) Eukaryotic chromosomes are found inside a membrane- bound compartment called a nucleus. (2) Eukaryotic cells are often much larger. (3) Eukaryotic cells contain extensive amounts of internal- (4) Eukaryotic cells feature a diverse and dynamic cytoskeleton.

Organelles:

membrane-bound structures in cell, have specific shape and function --allow cells to have a divided cytoplasm, compartmentalize specific functions. --increase chemical reaction efficiency by separating incompatible chemical reactions and grouping enzymes and substrates together.

Basic prokaryotic cell structure

plasma membrane surrounds the cytoplasm, a term that includes all the contents of the cell. • few or no substructures separated from the rest of the cell by internal membranes. • tough cell wall for protection, shape and structure which lack a membrane-bound nucleus & well-defined organelles. The most numerous intracellular structure is the ribosome, the site of protein synthesis in all living organisms.

Rough Endoplasmic Reticulum

structure: network of membrane bound tubes and sacs studded with ribosomes the interior is called the lumen, (remember the Rough ER is continuous with the nuclear envelope) Function: ribosomes on the RER synthesize proteins, new proteins are folded and processed and moltimetric proteins are assembled in the rough ER lumen, proteins are glycosolated Proteins in the RER have special destinations, some remain in the ER while others are sent to the golgi, proteins secreted from the golgi are direct to the lysosomes or the cell membrane, still others are secreted to the cell exterior, A number of other proteins in a cell, including those destined for the nucleus, peroxisomes, and mitochondria, are targeted for synthesis on free ribosomes.