Cells Flashcards
What does TGN stand for?
The TGN is the trans Golgi network. (trans meaning far away)
What are the two types of microtubules?
An axonemal and cytoplasmic microtubules. Axonemal is part of structures involved in cell movement.
Where are cytoplasmic microtubules located?
In cytosol
What are the two motor MAP’s that move along the microtubules?
Kinesin and Dynein
What does IF stand for?
Intermediate Filaments
What are the main functions of intermediate filaments?
They provide structural and mechanical support
What does MF stand for?
Microfilaments or F-actin
What is myosin?
A motor protein that interacts with F-actin to help with vesicle transport
What is the function of taxol?
It is a protein that prevents the disassembly of MT’s
List three contents of the nucleus:
Chromatin, nucleoplasm and nucleolus
What is chromatin made out of?
DNA and histones
What does ONM stand for?
The Outer Nuclear Membrane
What does INM stand for?
Inner Nuclear Membrane
T or F: The ONM connects to the nuclear lamina
False. The Inner Nuclear Membrane does
What is the nuclear lamina?
A thin mesh of proteins bound to the INM.
What does NPC stand for?
The Nuclear Pore Complex.
What are nuclear pores?
Gateways between cytoplasm and nucleoplasm where the inner and outer mem. fuse
What are FG-repeat domains?
They are amino acids that create a hydrophobic curtain across the NP’s.
What does NLS stand for?
Nuclear Localization Signal
What is the nuclear localization signal?
Positively charged amino acids within a protein sequence. It regulates protein movement in nucleus.
What do importin proteins do?
They import proteins.
What is catastrophe of the MT?
This is the shrinking, or breakdown of MT at the plus end.
Where does ribosome biogenesis occur?
Inside the nucleolus
What is a virion and where does it exist?
A virion is an inanimate virus that is outside of a cell
What are the two types of viral infections?
Lytic and integrative
Describe the difference between a lytic and integrative virus
Lytic produces virus particles until the cell dies. Integrative inserts virus DNA to host and impairs function.
Name the three types of proteins associated with cell membranes.
Integral, peripheral and lipid-anchored
Where are integral proteins located?
They span across the lipid bilayer, parallel to the lipids.
Where are peripheral proteins located?
They are associated with the surface of the lipid bilayer
T or F: biological membranes are symmetrical.
False. The two leaflets have very distinct lipid compositions.
T or F: saturated lipids reduce fluidity in the membrane.
True.
Which two factors influence membrane fluidity the most?
The nature of lipids(saturated or not) and the temperature.
How is cholesterol related to the membrane?
It alters the packing and flexibility of lipids, regulating fluidity.
Name the four basic mechanisms for moving molecules across membranes.
Simple diffusion, diffusion through a channel, facilitated diffusion and active transport.
Which of the three membrane proteins make up ion channels?
The integral proteins
What is a ligand-gated channel?
A membrane channel which responds to the binding of a specific molecule, such as acetylcholine.
What is a glycocalyx?
An assembly of carbohydrate groups on the outside of the plasma mem.
What are proteoglycans?
Proteins with chains of polysaccharides
Name some of the components of a plant cell wall.
Cellulose, hemicellulose, pectin and other proteins.
What is clathrin?
A protein used to form coated vesicles.
What is the main function of peroxisomes?
They are involved in the oxidation of toxic molecules.
Explain the endosymbiont theory.
Eukaryotic cells tarce back to an anaerobic prokaryote engulfing an aerobic bacterium.
Where can porins be located?
They are the large channels in the outer mitochondrial membrane.
What is the function of cristae and where can they be found?
They increase the surface area of the inner mitochondrial membrane for aerobic respiration and ATP formation.
Which are the two aqueous compartments of the mitochondria?
The intermembrane space and the matrix.
Where is mitochondrial DNA (mtDNA) located?
In the mitochondrial matrix.
Name a function of the mitochondrial matrix.
Encodes polypeptides that are later integrated into the IMM, ribosomes and tRNA.
Name some of the compartments of the endomembrane system.
The ER, Golgi complex, lysosomes, endosomes, vesicles and plant vacuoles.
What is a signal sequence?
A hydrophobic amino acid chain on proteins that direct synthesis to the ER
What is it called when a protein moves through a channel into the ER?
Co-translational import. (This WILL be on the test!)
What is an SRP receptor?
It reads the signal recognition particle on the ribosome and stops translation until the translocon opens.
What happens to a protein once it is synthesized in the ER?
- It is retained in the ER or 2. It goes to the Golgi complex for modification and delivery.
What is the ER-Golgi Intermediate Compartment?
The region between the ER and Golgi complex where vesicles fuse.
What are the four parts of vesicular transport?
Movement, tethering, docking and fusion
What process does a SNARE protein assist in?
The docking in vesicular transport
What happens to proteins that leave the CGN?
They will either go to the next Golgi station or be shipped back to the ER.
Which part of the cell is considered the ‘processing plant?’
The Golgi complex
T of F: Vesicular transport occurs in coated vesicles.
True.
Name the two function of the vesicle coat.
Helps to form the vesicle and selects the cargo for the vesicle.
Explain the difference between COPI and COPII.
COPI vesicles move from the Golgi complex to the ER, while COPII moves from the ER to Golgi complex.
Explain the major steps of apoptosis.
Stimuli -> Bax protein -> Cytochrome C -> Procaspase9 -> Caspase9 -> Execution Procaspase -> Execution Caspase
What are lysosomes?
Acidic digestive organelles.
What is the process of autophagy?
When lysosomes destroy organelles and replace them.
What is the cytoskeleton?
A network of tubules and filaments in the cytosol of eukaryotes.
Name a function of the cytoskeleton.
Structural support, spatial organization, intracellular transport and motility.
T or F: The motor protein Kinesin moves towards the plus end of the MT.
True
What is an autolysosome made out of?
A lysosome and an ER-derived autophagic vacuole fused together.
What are protofilaments?
They make up the walls of microtubules and are comprised of globular proteins.
What does MAP stand for?
Microtubule-associated proteins.
