plasma membrane is usually enclosed in a that is often covered with a (layer of proteins and/or sugars) cell wall capsule do not completely lack organelles; the plasma membrane and ribosomes are both present and are considered organelles AKA bacteria, prokaryotic cells are typically 1-10 in diameter m Compartments in eukaryotic cells (cell regions, organelles) two general regions inside the cell: cytoplasm and nucleoplasm cytoplasm everything outside the nucleus and within the plasma membrane; contains fluid cytosol and organelles – nucleoplasm everything within the nuclear membrane – membranes separate cell regions have nonpolar regions that help form a barrier between aqueous regions allow for some selection in what can cross a membrane (more details later) nucleus the center” of the cell – “control typically large (~5 m) and singular nuclear envelope double membrane surrounding the nucleus nuclear pores protein complexes that cross both membranes and regulate passage – chromatin DNA-protein complex – have granular appearance; easily stained for microscopy (“chrom-” = color) DNA kept ready for message transcription and DNA replication “unpacked” proteins protect DNA and help maintain structure and function chromosomes condensed or DNA ready for cell division (“-some” = body) – “packed” nucleoli regions of ribosome subunit assembly – appears different due to high RNA and protein concentration (no membrane) ribosomal RNA (rRNA) transcribed from DNA there proteins (imported from cytoplasm) join with rRNA at a nucleolus to from ribosome subunits ribosome subunits are exported to the cytoplasm through nuclear pores ribosomes the sites of protein synthesis – ribosomes are granular bodies with three RNA strands and about 75 associated proteins two main subunits, large and small perform the enzymatic activity for forming peptide bonds, serve as the sites of translation prokaryotic ribosome subunits are both smaller than the corresponding subunits in eukaryotes in eukaryotes
plasma membrane is usually enclosed in a cell wall that is often covered with a capsule (layer of proteins and/or sugars) do not completely lack organelles; the plasma membrane and ribosomes are both present and are considered organelles AKA bacteria, prokaryotic cells are typically 1-10 m in diameter Compartments in eukaryotic cells (cell regions, organelles) two general regions inside the cell: cytoplasm and nucleoplasm cytoplasm – everything outside the nucleus and within the plasma membrane; contains fluid cytosol and organelles nucleoplasm – everything within the nuclear membrane membranes separate cell regions have nonpolar regions that help form a barrier between aqueous regions allow for some selection in what can cross a membrane (more details later) nucleus – the “control center” of the cell typically large (~5 m) and singular nuclear envelope double membrane surrounding the nucleus nuclear pores – protein complexes that cross both membranes and regulate passage chromatin – DNA-protein complex have granular appearance; easily stained for microscopy (“chrom-” = color) “unpacked” DNA kept ready for message transcription and DNA replication proteins protect DNA and help maintain structure and function chromosomes – condensed or “packed” DNA ready for cell division (“-some” = body) nucleoli – regions of ribosome subunit assembly appears different due to high RNA and protein concentration (no membrane) ribosomal RNA (rRNA) transcribed from DNA there proteins (imported from cytoplasm) join with rRNA at a nucleolus to from ribosome subunits ribosome subunits are exported to the cytoplasm through nuclear pores ribosomes – the sites of protein synthesis ribosomes are granular bodies with three RNA strands and about 75 associated proteins two main subunits, large and small perform the enzymatic activity for forming peptide bonds, serve as the sites of translation prokaryotic ribosome subunits are both smaller than the corresponding subunits in eukaryotes in eukaryotes
chapter6activity.docx