Untitled Quiz

Structural components in animal cells, providing support and strength to cells and tissues.

A step-wise process involving monomers forming dimers, tetramers, and finally, filaments.

A type of intermediate filament found in epithelial tissues, helping cells adhere and resist stretching.

Intermediate filaments in connective tissues providing structural support.

Largest cytoskeletal elements found in all eukaryotic cells, crucial for cell structure and movement.

Initiated at microtubule-organizing centers (MTOCs), like centrosomes and basal bodies, using tubulin monomers.

A microtubule-organizing center near the nucleus in non-dividing cells.

Globular protein that forms the building block of microtubules, existing as alpha & beta dimers.

Microtubules can grow or shrink rapidly in length. This process is controlled and regulated within the cell.

When GTP is high on a microtubule dimer, it promotes growth. GTP has higher affinity than GDP.

New GTP-bound dimers add to the microtubule's plus-end, causing it to elongate.

Actin filaments add monomers at the plus end and at the minus-end at the same time. The rate of addition to both ends is equal. This process maintains constant length

Actin filaments are formed from actin monomers that associate together to form a structure. ARP 2/3 are proteins involved in nucleation process

Actin molecules bound to ATP has a higher affinity than ADP and are added to the plus end; thus, controlling Actin Treadmilling.

Actin filaments are crucial for cell processes like cell division (cytokinesis) and movement (cell migration).

The ability of cells to move, involving a coordinated series of steps including actin polymerization at the front, adhesion to the extracellular matrix, contraction by myosin, and retraction at the back.

The endoplasmic reticulum (ER) is involved in lipid and protein production, detoxification of drugs, and steroid hormone synthesis.

The Golgi apparatus modifies and sorts proteins, packages them for transport, and produces non-glycerol containing phospholipids.

Lysosomes are organelles that degrade macromolecules and organelles by breaking them down into smaller components, acting as the cell's recycling center.

Disulfide bonds form between cysteine amino acids within proteins, only in the lumen of the ER and the extracellular matrix.

The process of adding carbohydrate sequences to proteins, often happening in the ER and important for protein function and targeting.

A quality control system within the ER that identifies and degrades misfolded proteins, ensuring that only correctly folded proteins leave the ER.

The unfolded protein response (UPR) is activated when misfolded proteins accumulate in the ER, leading to a shutdown of protein production and potentially cell death.

Vesicles carrying cargo from the Golgi apparatus travel to the plasma membrane for release. This process can be regulated or constitutive.

Unregulated release of cargo from the Golgi to the plasma membrane, occurring continuously at a moderate pace.

Release of cargo from the Golgi to the plasma membrane triggered by an external signal.

A process where cells internalize specific molecules by binding to receptors on the plasma membrane, forming vesicles that are then transported to lysosomes.

Hormones released into the bloodstream to act on distant target cells.

Local signaling where a cell releases a signal to affect nearby cells.

Specialized form of signaling in the nervous system where neurons communicate directly with each other via synapses.

Cells communicate by direct contact, with a membrane-bound signal requiring direct interaction with a receptor on another cell.

These molecules can cross the cell membrane and bind to receptors inside the cell.

These molecules bind to receptors on the cell membrane, initiating a signaling cascade.

The process where coat proteins bind to a membrane, causing it to pucker and form a vesicle. This is the first step in vesicular transport.

A type of vesicle formation where clathrin coat proteins, with the help of adaptin, bind to receptors on the membrane to capture cargo.

A type of vesicle formation where COP proteins directly bind to receptors on the membrane, capturing specific cargo without adaptin.

Dynamin pinches off the vesicle from the membrane using energy from ATP. Think of it as the scissors that cut the bubble off the surface.

Rab proteins on the vesicle act as a postal code, binding to specific tethering proteins on the target membrane. This ensures the vesicle reaches the correct location.

V-SNAREs on the vesicle and t-SNAREs on the target membrane interact, pulling the vesicle close to the membrane and causing fusion. This releases the cargo into the target compartment.

COPII coat proteins are used to transport vesicles from the ER to the Golgi apparatus.

COPI coat proteins and dynein motor proteins are responsible for transport of proteins back from the Golgi to the ER.

PKA phosphorylates and inactivates glycogen synthase, the enzyme responsible for building glycogen from glucose. This prevents glucose storage as glycogen.

G-proteins are inactivated by various mechanisms, including removal of signaling molecules, GTP hydrolysis, arrestin binding, and receptor endocytosis.

Cyclic AMP phosphodiesterase is an enzyme that breaks down cyclic AMP (cAMP). By reducing cAMP levels, it ultimately decreases the activation of PKA and its downstream effects.

Receptor tyrosine kinase (RTK) is a type of enzyme-coupled receptor that plays a key role in cell signaling. It binds to signaling molecules and triggers a signaling cascade.

AKT is activated through a multi-step process: 1. Signaling molecules bind RTK. 2. RTK dimerizes and cross-phosphorylates. 3. Pi3K binds and is activated. 4. Pi3K phosphorylates PIP2 to PIP3. 5. PIP3 acts as a docking site for AKT and PK1, activating them. 6. Docked PK1 and cytosolic PK2 bind and activate AKT.

The RTK-AKT pathway, triggered by insulin, lowers blood glucose by: 1. Promoting glucose uptake into cells by stimulating the insertion of glucose transporters. 2. Inactivating glycogen phosphorylase and phosphorylase kinase, thereby inhibiting glycogen breakdown.

AKT phosphorylates proteins responsible for holding vesicles containing glucose transporter at the trans-Golgi. This leads to their release and insertion into the cell membrane, increasing glucose uptake.

AKT phosphorylates protein phosphatase 1 (PP1), which removes phosphate groups from phosphorylase kinase and glycogen phosphorylase. This deactivation prevents the breakdown of glycogen into glucose.