BIO 2120 Exam 3 - Questions and Answers What is the key to maintaining the functional organization of a cell? The selectivity of vesicular transport- vesi... [Show More] cles must recognize and fuse only with the appropriate target membrane Transport vesicles from the ER are coated with ___. Cytosolic coat proteins- coats assemble as the vesicle buds off and are removed in the cytosol before it reaches its target. The vesicles fuse with the target membrane, empty their cargo, and their membrane proteins diffuse within the plane of the target membrane 3 families of vesicle coat proteins 1. COPII-coated vesicles carry proteins from the ER to the ERGIC and on to the Golgi apparatus. 2. COPI-coated vesicles bud from the ERGIC or Golgi and carry their cargo back, returning proteins to earlier compartments. 3. Clathrin-coated vesicles transport in both directions between the trans Golgi network, endosomes, lysosomes, and plasma membrane Fusion of a transport vesicle with its target: 1. The vesicle must recognize the correct target membrane. 2. Vesicle and target membrane must fuse, delivering the contents to the target organelle. Interaction between transport vesicles and target membranes is mediated by ___ and ___. Tethering factors and small-GTP binding proteins (Rab proteins) Lysosomes membrane-enclosed organelles that contain enzymes to break down all types of biological polymers. They are the digestive system of the cell. They can vary in size and shape depending on the materials that have been taken up for digestion Endocytosis process by which a cell takes material into the cell by infolding of the cell membrane Lysosomes use this! How are lysosomes formed? Formed when transport vesicles from the trans-Golgi network fuse with a late endosome Endosomes Represent an intersection between the secretory pathway and the endocytic pathway
Lysosomes contain about ___ different degradative enzymes 60 Lysosomal storage diseases Caused by mutations in genes that encode degradative enzymes found in lysosomes 3 types of endosomes Early- fuse with endocytic vesicles from the plasma membrane and separate molecules for recycling from molecules destined for degradation in lysosomes Recycling Late Mitochondria Generate energy from the breakdown of lipids and carbohydrates Surrounded by a double-membrane system, separated by an intermembrane space Chloroplasts Use sunlight energy to generate ATP, and reducing power to synthesize carbohydrates from CO2 and H2O Peroxisomes Contain enzymes involved in a variety of metabolic pathways Single-membrane organelles containing enzymes involved in many metabolic reactions- do NOT have their own genomes Can replicate by division Matrix The interior of a mitochondrion (the region bounded by the inner membrane). Cristae Numerous folds of the inner membrane of the mitochondria Increase the amount of membrane available to be occupied by enzyme complexes involved in oxidative phosphorylation Where does energy production by oxidative phosphorylation take place? Inner mitochondrial membrane Electron transfer is coupled to ___ across the ____, which in turn drives ___. Generation of a proton gradient; inner mitochondrial membrane; ATP synthesis Inner membrane is ___ to most ions and small molecules Impermeable This trait is critical to maintaining the proton gradient The ____ is the principal site of ATP generation. [Show Less]
