Cell Biology Concepts and Mechanisms

Intermediate filaments

Like lamins.

Actin binding protein

Involved in formation of networks.

Polarity of cytoskeletal filaments

Important for cellular functions.

ATP binding to myosin

Causes it to dissociate.

Calcium

Key regulator of muscle contraction.

Asymmetry of phospholipid bilayer

Causes distribution of cholesterol.

Glycocalyx

Refers to glucose layer on cell.

Cell to cell junctions

Hemidesmosomes are not involved.

Actin filaments

Bind to adherens junctions.

Ribosomes

Complexes composed of RNA & Protein.

Nucleolus and ribosomes

Organelles not enclosed by a membrane.

Rough Endoplasmic Reticulum (RER)

Has a membrane continuous with the nucleus.

Smooth Endoplasmic Reticulum (SER)

Plays a role in lipid synthesis.

Pulse-chase experiment

Involves pulsing radioactive marker & tracking protein.

N-terminus signal sequence

Recognized by Signal Recognition Particle (SRP).

Translocon

Proteins destined for ER lumen pass through it.

Flippases

Transport some membrane lipids to other leaflets.

Chaperone proteins

Play a role in protein folding & removal of coat protein.

Tight junctions

So close there is no space between them.

Selectins

Cell surface receptors that bind to carbohydrates.

Clathrin budding

Initiated by ARF1, a GTP binding protein.

KDEL sequence defect

Proteins don't get recycled to ER.

Mitochondria and chloroplasts

Proteins are synthesized in matrix & stroma.

Stroma

Fatty acids are converted to Acyl CoA.

Intermembrane space of mitochondria

Fluid composition resembles cytosol due to porins.

Proton gradient in mitochondria

Established by pumping protons into the intermembrane space.

NADH

Involved in oxidative phosphorylation.

Ultimate source of electrons in light reactions

Water (H₂O).

Smallest protein filament in cytoskeleton

Actin filaments.