What types of molecules make up the membranes of different cellular compartments?
phospholipids are the molecules that make up the plasma membrane and all of the membranes of a human cell (nuclear membrane, lysosomal membrane, both mitochondrial membranes, endoplasmic reticulum, Golgi apparatus). They have a polar, hydrophilic head and two non-polar, hydrophobic tails.
- Polar (hydrophillic) head group and nonpolar (hydrophobic) tail. - Phospholipids are a lipid with a phosphate group in its molecule and are major membrane lipids. It has glycerol which is important b/c it amkes up part of the head, phopahte group, & choline. Connects phos. to structure and used as energy source. as a backbone phosphate group and a choline group attached to the glycerol. -Sphingolipids is the second major membrane lipids, with ceramide backbone on a phosphate group
-Lipids with a carbohydrate attached by a glycosidic bond. -Role is to maintain stability of the membrane and to facilitate cellular recognition. -Found exclusively in the non-cytosolic leaflet of cell membranes. -Must have at least 1 sugar group, sometimes many. - Animal glycolipids are based on sphingosine, while plant and bacterial glycolipids are based on glycerol
Compare and contrast the cellular organization of prokaryotes and eukaryotes
-Begins in cytosol; transcription (DNA->RNA) in the nucleus. Afterwards, translation (mRNA-> proteins) occurs with the help of the ribosomes in the cytoplasm. -Translation: 2 ribosomial subunits link into the mRNA (initiation), followed by elongation, amino acids are added to the growing chain by tRNAs. Ribosomes reads the nucleotides of mRNA (codons to nucleotides on the tRNA, called the anticodon). Finally, termination, the ribosome unbinds from the mRNA, and the amino acid chain goes on to be processed and folded to make the final functioning protein.
structure and function of the nuclear envelope
- Two layered membrane (made of a lipid bilayer) that encases the nucleus of a eukaryotic cell -Outer: contiguous with the endoplasmic reticulum -Inner: constituted by a network of filaments (nuclear lamina) also acts as a shield -Mechanical support: composed of filaments and membranes associated proteins inside nucleus and regulates improtant cellular events (ex. DNA replication) - Separates nucleus from other cell organelles and have nuclear pores to regulate the exchange of substances (ex. proteins and RNA) between the nucleus and cytoplasm