Lecture 5 Flashcards
What is the Endomembrane System? What does it include?
It is a system of membrane bound organelles that originated from the infoldings of the cell membrane, it is connected with vesicles. It includes the ER, Golgi, Lysosome, Mitochondria and the outer nuclear membrane because it morphs into the ER
What is the ER? What does it do?
The Endoplasmic Reticulum and has smooth version, SER and a rough version, RER that have different functions
What is the RER? What does it do?
The Rough Endoplasmic Reticulum has ribosomes imbedded in it which synthesis proteins associated with the endomembrane system and are quality control for proteins
What is a ribosome?
Consists of 2 major protein components (small and large) and associate rRNA. Its a translation enzyme
What is the SER? What does it do?
The Smooth Endoplasmic Reticulum does not have ribosomes in it. It is storage for enzymes, synthesizes phospholipids and steroids’ and detoxifies drugs and alcohol
What is the Golgi Apparatus? What does it do?
The Golgi Apparatus is a set of flattened membranes sacks called cisterna. The Golgi receives cargo from the ER and sorts it so the cargo can go to different destinations in the Endomembrane system.
What are the three sections of the Golgi called?
Cis-receiving side. Medial-middle. Trans-exit
What are the two proposed ways of Golgi trafficking?
Vesicle Trafficking and Cisternal Maturation
What is Cisternal Maturation?
This is when the cis cisterna receives cargo and then moves to become the medial cisterna. Vesicles come and take its place. The new medial cisterna then become the trans cisterna and the old trans cisterna will become vesicles. This process repeats.
What is Vesical Trafficking?
Vesicles move throughout the Golgi moving cargo from one cisterna to the next
What is a Lysosome? What does it do?
A lysosome digests macromolecules from endocytosis and is full of hydrolytic enzymes that work best at pH 5. They actively pump H+ to maintain this low pH so they don’t accidentally commit autophagy
What is Autophagy?
Organellular recycling. A lysosome can purposely burst to comit apoptosis
What is Apoptosis?
The cell uses the lysosomes to commit suicide
What is Tay Sachs?
A disease in which the lysosome lacks a certain enzyme that breaks down a lipid. This lipid accumulates and causes neuronal cell death. Its terminal
What is the Cytoskeleton?
A network of fibers in the cell that maintain shape structure and mobility. It has 3 main components
What are the 3 components of the cytoskeleton?
Microfilaments, microtubules and intermediate filaments
What are microfilaments? What do they do?
A microfilament is a polymer of actin. Its function is tension resistance and assists in movement: muscle contraction and cytokinesis.
What is myosin? How does it work?
Myosin is the motor protein used by microfilaments to allow movement. The myosin does a bicep curl to contract muscles
What are microtubules?
A microtubule is a polymer of tubulin and its function is compression resistance. It is made of protofilaments and has the motor proteins kinesin and dynein
What is a tubulin?
A dimer of alpha and beta tubulin dimers
What is a protofilament?
A strand of alpha beta tubulin. 13 protofilaments will come together to create a microtubule
What is Kinesin? What does it do?
A positive end directed MT motor protein. It carry’s vesicles across microtubules in a monkey bar motion. It is a man walking
What is Dynein? What does it do?
A negative end directed MT motor protein. It is unclear how it moves but it helps eukaryotic flagellum move
What is a dimer?
Two covalently bound things
What is an intermediate filament? What dos it do?
A rope like filament that assists in tension resistance. It is heterogenous, lacks directionality and has no associated motor protons. An example would be laminin which make up the nuclear lamina
What is the nucleus? What does it do?
It is the storage of DNA and the site of gene expression. It is double membraned and the outer membrane is continuous with the ER.
What is a nucleolus? What does it do?
It is the site of ribosomal subunit assembly. The subunits of ribosomes associate with rRNA here. The subunits leave the nucleus separate and come together in the cytoplasm during translation
What is the nuclear envelope?
Both nuclear membranes, its made of 2 lipid bilayers and a nuclear lamina. It protects the DNA
What is nuclear lamina?
The inner surface of the inner nuclear membrane, it provides support
