This of the cell allows incompatible chemical process

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This compartmentalization of the cell allows incompatible chemical process to occur simultaneously in the cell by separating them and providing the proper environment.In general biological membranes consist of a layer of lipids and phospholipids with proteins embedded in this layer or attached to its surface.Each type of membrane has its unique composition of lipids and proteins suited to its function, e.g. enzymes embedded in the membrane of mitochondria allow cellular respiration to occur here. CONCEPT 3. THE EUKARYOTIC CELL’S GENETIC INSTRUCTIONS ARE HOUSED IN THENUCLEUS AND CARRIED OUT BY THE RIBOSOMES.1. The Nucleus: Information Central. Controls the functions of the cell.
Large structure surrounded by double membrane; contains nucleolus and chromosomes.It averages 5 m in diameter.Nuclear envelopeis made of a double membrane: two concentric membranes that separate its contents from the cytoplasm. Each is a lipid bilayer!The two layers are separated by a space of 20-40 nm.Nuclear poresabout 100 nm in diameter allow the passage of material in and out of the nucleus.The inner and outer membranes are fused around the pore.Each pore is ringed by proteins, the pore complexthat regulate the passage of macromolecules in and out of the nucleus.The nuclear side of the membrane is lined with a netlike structure of proteins called the nuclear laminathat maintains the shape of the nucleus.The nuclear matrixis made by framework of fibers extending throughout the nuclear interior. Its function is not completely understood.See fig. 6.9.Check this site: 2. Ribosomes: Protein FactoriesGranules composed of RNA and protein. They do not have a surrounding membrane.Some attached to inner membranes of the endoplasmic reticulum or nuclear membrane andothers are free in cytosol.Synthesis of polypeptides.Bound ribosomesmake proteins mainly destined to make membranes.Free ribosomesmake proteins that are usually dissolved in the cytosol. Ribosomes may alternate their roles in protein making.Ribosomes are made of two subunits.The subunits are identified by the letter “S”, which means: “The unit S means Svedbergunits, ameasure of the rate of sedimentation of a particle in a centrifuge, where the sedimentation rate is associated with the size of the particle. Svedberg units are not additive - two subunits together can have Svedberg values that do not add up to that of the entire ribosome.”The svedberg is actually a measure of time; it is defined as exactly 10−13seconds(100 fs).The Svedberg unit (S) offers a measure of particle size based on its rate of travel in a tube subjected to high.”3. Chromosomes.DNA and its associated proteins form thin fibers called chromatin.Chromatin condenses as it coils up before cell division and form the chromosomesChromosomes become visible as rod-like structures that can be stained dark.Each eukaryotic species has its characteristic number of chromosomes, e. g. 46 in human.
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