BI110 Lecture Notes - Lecture 17: Nuclear Pore, Nuclear Membrane, Nucleolus
Bi110 lesson 17
glycoproteins, it is relatively soft
• - in bone, the network is impregnated with mineral crystals,
producing a structure that is dense and hard, yet elastic
• - fibronectins bind to receptor proteins (integrins) in the plasma
membrane, which bind to microfilaments
➢ nucleus
• ● the nucleus is separated from the cytoplasm by the nuclear envelope, which
consists of two membranes
• ● one membrane is layered just inside the other and separated by a narrow space
• ● nuclear pore complexes embedded in the nuclear envelope regulate the
transport of proteins and RNA molecules between the nucleus and cytoplasm
• ● a channel through the nuclear pore complex, a nuclear pore, is the path for the
assisted exchange of large molecules with the cytoplasm
• ● the space inside the nucleus mostly contains chromatin, a combination of DNA
and proteins. loose, uncoiled form
• ● in eukaryotes, each DNA molecule is linear. organized into a tight, condensed
form with its protein into a specific eukaryotic chromosome
• ● a eukaryotic nucleus contains one or more nucleoli, formed around the genes
coding for rRNA molecules of ribosomes
• ● ribosomal subunits are formed in nucleoli and exit the nucleus through nuclear
pore complexes. in the cytoplasm, they join on mRNAs to form ribosomes
• ● expression of genes is carefully controlled, according with the function of each
cell
➢ eukaryotic ribosomes
