Controls passage of material into & out of cell (acts a barrier b/w internal & external enviro) Basic structural unit (phospholipid bilayer); Membrane proteins-amphipathic
What type of proteins make up the membrane proteins?
Integral proteins, Extrinsic Proteins, Glycoproteins
Integral Proteins
Extend through entire membrane (Transmembrane) must have hyrophobic & hydrophilic regions
Extrinsic Proteins
Assoc. w/ either cytoplasmic or extracellular region of membrane
Glycoproteins
Covalently linked to sugar residues on outside of cell. Sugar acts as recognition site
Membrane proteins serve what functions?
Enzymes, Transport, & Receptors
What is the purpose of the nucleus?
A repository of genetic information
What is the nuclear envelope?
A double membrane made up of nuclear pores which regulate passage of material b/w nucleus and cytoplasm
What is DNA?
2 comlimentary strands of nucleotides held together by hydrogen bonds b/w bases
Chromatin DNA is packaged with what type of proteins?
Histone proteins-Heterochromatin and Euchromatin
Heterochromatin
Not very active DNA
Euchromatin
DNA is more active & chromatin is dispersed
What is the Nucleolus?
Place where ribosomes are organized & synthesized. Most DNA stored here
What is the function of the Nucleus?
Replication of DNA to provide continuity of genetic info and Transcription of DNA to mRNA for protein synthesis
Endoplasmic reticulum
An organelle that is an interconnected network of tubules and contains the Rough Endoplasmic Reticulum (RER) and Smooth Endo. Ret. (SER)
Rough Endo. Reticulum
Ribosomes are attached and protein synthesis is carried out
Smooth Endo. Reticulum
NO ribosomes attached; No protein synthesis; Synthesis of lipids & steroids; Detox of some drugs; sequesters Ca ions in muscle cells
Golgi Apparatus
Stack of flatteneds sacs which process and package secreted proteins and integral membrane proteins, Lysosomal proteins (ex. postal service-sends everything on its way)
Lysosomes
Organelles that contain digestive enzymes; Resp. for breaking down or digesting material that has worn away or destined for disposal; Cellular recycling; Over 40 hydrolytic enymes that breakdown macromolecules; active in acidic environ.
Mitochondrion
Membrane-enclosed organelle where most of the energy of the cell is generated. Has 2 membranes inner/outer. Inner membrane contains proteins of elect. trans. system; Contains circular DNA and ribosomes
Peroxisomes
aka Microbodies; prevalent in kidney & liver cells; Contain catalase & peroxidases; Generate & breakdown hyrdo. peroxide into H20 and O2; also break down long chain fatty acids
Ribosomes
Site of protein synthesis; Composed of ribosomal protein and rRNA; Found in mitochondria, cytoplasm, and RER; found in both prokaryotic & eukaryotic cells
Cytoskeleton
Provides internal framework for cell; Provides for cellular mvmt. (internal-chromosomes during cell division, external-cilia & flagella); Provide binding sites for organelles; Controls vesicular traffic; Composed of microtubules, int. filaments, microfila
Microtubules
Biggest and hollow tubes; Composed of alpha & beta tubulin; form cilia & flagella; Functions incl. positioning of organelles; mvmt of cells; mvmt of organelles; changes in cell shape during embryogenesis
Microfilaments
Much thinner rod-like; Composed of actin; G-actin (unpolymerized), F-actin (polymerized) Function incl. muscle contraction, amoeboid mvmt of phagocytic cells, Cytoplasmic streaming, cleavage furrow during cell division
Intermediate Filaments
Intermediate in size; Fibrous; more diverse in composition than other skeletal elements; stable; provides mechanical strength
