Cytoskeleton and Protein Transport – Fill-in-the-Blank Flashcards

A comprehensive set of fill-in-the-blank flashcards covering cell structure, cytoskeleton dynamics, nuclear transport, and the endomembrane secretory pathway.

In prokaryotes, the region where the circular chromosome is super-coiled is called the _.

nucleoid

Small circular DNA molecules acquired from other bacteria are known as _.

plasmids

Protein synthesis occurs on ribosomes made of proteins and _.

rRNA

The phospholipid bilayer surrounding a prokaryotic cell is the _.

plasma membrane

Light-dependent pigments in photosynthetic bacteria are located on internal membranes that extend from the _.

plasma membrane

Mitochondria and chloroplasts are classified as _-derived organelles.

endosymbiont

The collection of organelles derived from the ER is called the _ system.

endomembrane

The _ is a double-membraned structure that stores eukaryotic DNA.

nucleus

The dense region inside the nucleus where rRNA is transcribed is the _.

nucleolus

Loosely packed DNA–protein material inside the nucleus is called _.

chromatin

Openings in the nuclear envelope that regulate traffic are nuclear _ complexes.

pore

Ribosomes destined to make secreted proteins attach to the surface of the _ ER.

rough

The _ ER is the main site of lipid, fatty-acid, and steroid synthesis.

smooth

Proteins leave the ER enclosed in membrane-bound spheres called _.

vesicles

The side of the Golgi apparatus nearest the nucleus is the _ face.

cis

The acidic organelle responsible for digesting old organelles and macromolecules is the _.

lysosome

Redox reactions such as alcohol detoxification occur in the _.

peroxisome

Large plant-cell organelles that store ions and provide turgor pressure are _.

vacuoles

The three major cytoskeletal filaments are actin filaments, intermediate filaments, and _.

microtubules

Actin filament growth at one end drives cellular movement known as _.

cell crawling

Muscle contraction relies on interactions between actin and the motor protein _.

myosin

Intermediate filaments are especially important for reinforcing the _ envelope.

nuclear

Microtubules are polymers of α- and β-tubulin _.

heterodimers

Centrosomes act as microtubule _ centers in animal cells.

organizing (MTOCs)

The motor protein _ moves cargo toward the plus end of a microtubule.

kinesin

_ moves cargo toward the minus end of a microtubule and powers ciliary bending.

dynein

Eukaryotic cilia and flagella share a _ microtubule arrangement.

9+2

Proteins that enter the nucleus contain a sequence called the _.

nuclear localization signal (NLS)

Importin binds to the NLS and escorts cargo through the nuclear _.

pore

Proteins that must exit the nucleus carry a nuclear _ signal.

export (NES)

The cytoplasmic particle that recognizes the ER signal sequence is the _.

signal recognition particle (SRP)

During co-translational import, the ER signal sequence is removed by _ peptidase.

signal

In the pulse-chase experiment, radioactive proteins moved from ER → Golgi → vesicles → _.

plasma membrane

Glycosylation tags in the trans-Golgi act like postal _ directing proteins to destinations.

zip codes

Secreted polypeptides are ~20 amino acids shorter because the _ sequence is cleaved.

signal (ER signal)

Vesicles travel along microtubules in an _-dependent manner.

ATP

Pancreatic acinar cells have abundant rough ER because they specialize in protein _.

secretion

In prokaryotes, the electron transport chain resides in the _ membrane.

plasma

Peroxisomes help neutralize reactive _ species.

oxygen

Plant cell walls are outside the plasma membrane, whereas animal cells are supported by an _ matrix.

extracellular

Microtubules shrink when the concentration of free tubulin heterodimers is _.

low

During cytokinesis in animal cells, a contractile ring of actin and _ pinches the cell in two.

myosin

NLS motifs are rich in the basic amino acids lysine and _.

arginine

Organelles considered part of the endomembrane system are derived from the _ reticulum.

endoplasmic