Cytoskeleton Flashcards: Fibers, Motors & Functions
Practice cytoskeletal fibers, motor tracks, cell division, and ciliary patterns with 50 English flashcards and short checks for ambiguous clues.
About this deck
Practice cytoskeleton structure and function with 50 English flashcards for secondary and introductory-college biology. The focus is on telling actin filaments, microtubules, and intermediate filaments apart, then applying those distinctions to motors, cell structures, and short reasoning prompts. Basic cell knowledge is helpful; the cell organelle flashcards cover that prerequisite.
The cards map filament names to building proteins and structural properties, selected protein or shape clues back to filament families, motor names to tracks and specified travel directions, and named cell structures to their cytoskeletal components. Short error checks distinguish a fiber from its building protein or motor. Other prompts ask what information is missing when support, movement, cell division, vesicle transport, or ATP use does not identify a unique answer.
Start with the three filament families, their assembly, and polarity. Motor tracks and ATP use lead into the actin cortex, microvilli, keratins, nuclear lamins, the spindle, and the animal-cell contractile ring. Basic ciliary architecture and selected motor-direction exceptions then support the final mixed distinctions. Selected reverse prompts and related variants are separated; the review scheduler handles longer-term spacing. Every card carries the cytoskeleton tag.
This is text-based recall practice. It does not test diagram or micrograph identification. Exhaustive reverse cards, arbitrary name-to-example lists, exact filament diameters, detailed motor families, clinical diagnosis, drug treatment, bacterial cytoskeletons, and molecular regulation pathways are excluded to keep the deck focused. Typical ciliary patterns are taught with exceptions, not as universal motility rules. No complete biology course or examination alignment is claimed.
The questions, explanations, sequence, and metadata were written independently with AI assistance. Scientific facts were checked against research publications on cytoskeletal interactions and intermediate filaments, microtubule dynamics, motor proteins, microvilli, animal-cell cytokinesis, actin assembly, cell protrusion, motile cilia, and primary cilia. Source wording, exercises, and diagrams were not copied; those publications retain their own licenses, and scientific facts are not claimed as proprietary. Original material and the AI-generated decorative cover are dedicated under CC0 1.0 to the extent applicable rights exist. The cover is an abstract illustration, not a molecular diagram. This is independent study material without institutional endorsement.
Cards in this deck
Card 1
Question
What are the three major cytoskeletal filament families in animal cells?
Answer
Actin filaments (microfilaments), microtubules, and intermediate filaments.
Card 2
Question
Which protein builds microfilaments?
Answer
Actin.
Card 3
Question
Which two tubulin subunits pair to build microtubules?
Answer
Alpha-tubulin and beta-tubulin. Each building unit is an alpha–beta tubulin dimer.
Card 4
Question
Do all intermediate filaments use the same building protein?
Answer
No. Different cells use different intermediate-filament proteins, such as keratins, vimentin, and nuclear lamins.
Card 5
Question
What does filament polarity mean in the cytoskeleton?
Answer
The two ends have different molecular structures. Plus and minus label distinct ends, not electrical charges.
Card 6
Question
What is the basic shape of an actin filament?
Answer
Two intertwined strands of actin subunits. It is a thin filament, not a hollow tube.
Card 7
Question
Which major cytoskeletal filament forms a hollow tube?
Answer
A microtubule.
Card 8
Question
Which major cytoskeletal filament has a rope-like assembly of fibrous proteins?
Answer
An intermediate filament.
Card 9
Question
Which cytoskeletal filament is the track for myosin motors?
Answer
An actin filament.
Card 10
Question
Which major cytoskeletal filament family lacks distinct plus and minus ends?
Answer
Intermediate filaments. Actin filaments and microtubules are polar.
Card 11
Question
What directly powers the stepping of myosin, kinesin, and dynein motors?
Answer
ATP hydrolysis.
Card 12
Question
Which two motor-protein families move along microtubules?
Answer
Kinesins and dyneins.
Card 13
Question
Which filament network is especially prominent in the cortex just beneath an animal cell’s plasma membrane?
Answer
Actin filaments. The cortex helps control cell shape and surface mechanics.
Card 14
Question
Keratin networks belong to which cytoskeletal filament family?
Answer
Intermediate filaments.
Card 15
Question
What is microtubule dynamic instability?
Answer
Switching between growth and shrinkage. A microtubule can change length as tubulin subunits are added or lost.
Card 16
Question
A cargo moves by kinesin along a microtubule. Which component is the motor?
Answer
Kinesin. The microtubule is the track.
Card 17
Question
Which filaments form the supporting bundles inside microvilli?
Answer
Actin filaments.
Card 18
Question
Which proteins form the nuclear lamina beneath the inner nuclear membrane?
Answer
Lamins, members of the intermediate-filament protein family.
Card 19
Question
Which cytoskeletal filaments form the mitotic spindle?
Answer
Microtubules. Spindle microtubules help organize and separate chromosomes.
Card 20
Question
Cytoplasmic dynein carries cargo toward which end of a microtubule?
Answer
The minus end.
Card 21
Question
Which filament and motor form the main contractile machinery of the animal-cell cleavage ring?
Answer
Actin filaments and myosin II.
Card 22
Question
How can actin assembly help a crawling cell extend its leading edge?
Answer
Growing actin filaments can push the plasma membrane outward.
Card 23
Question
Which filaments form the axoneme, the internal framework of eukaryotic cilia and flagella?
Answer
Microtubules.
Card 24
Question
Conventional kinesin-1 carries cargo toward which end of a microtubule?
Answer
The plus end.
Card 25
Question
What mechanical role do intermediate-filament networks provide when a cell is stretched?
Answer
They help distribute tensile stress and resist damage from stretching.
Card 26
Question
In an animal-cell contractile ring, is myosin II a motor or an actin building subunit?
Answer
A motor. Actin supplies the filament subunits.
Card 27
Question
What does the typical 9 + 2 pattern of an airway motile cilium describe?
Answer
Nine outer microtubule doublets around two central single microtubules.
Card 28
Question
Does the name kinesin alone guarantee plus-end-directed movement?
Answer
No. Kinesin families differ; some move toward minus ends. Specify the kinesin type before assigning a direction.
Card 29
Question
How do the core filaments of microvilli differ from those of eukaryotic cilia?
Answer
Microvilli have actin bundles; cilia have a microtubule-based axoneme.
Card 30
Question
The nuclear lamina is built from which major filament family?
Answer
Intermediate filaments, specifically lamins.
Card 31
Question
In animal-cell division, which structure constricts the cell surface: the spindle or the contractile ring?
Answer
The contractile ring. Its actin–myosin machinery narrows the cleavage furrow.
Card 32
Question
What is a common role of a non-motile primary cilium?
Answer
Sensing and coordinating signals. It acts as a specialized signaling compartment.
Card 33
Question
Which motor family drives sliding between neighboring microtubule doublets in a motile cilium?
Answer
Axonemal dyneins. Structural constraints convert that sliding into bending.
Card 34
Question
Does vesicle transport by itself identify a microtubule track?
Answer
No. Vesicles can use microtubules or actin-based transport. The motor identity or filament composition supplies a better clue.
Card 35
Question
A prompt asks for the filament family containing keratin. Is keratin alone the requested answer?
Answer
No. Answer intermediate filaments. Keratin names a building protein, not the filament family.
Card 36
Question
What microtubule pattern is commonly used to describe a primary cilium?
Answer
The 9 + 0 pattern: nine outer doublets without a central pair. It is a typical description, not a universal rule for every cross-section.
Card 37
Question
A filament is assembled from alpha–beta tubulin dimers. Which filament family is it?
Answer
Microtubules.
Card 38
Question
What does the centrosome do for microtubules in many animal cells?
Answer
It acts as a microtubule-organizing center, helping nucleate and organize the microtubule array.
Card 39
Question
A vesicle is moved by myosin. Which filament supplies its track?
Answer
Actin. Myosin-based cargo transport uses actin filaments.
Card 40
Question
Why can’t a 9 + 0 axoneme alone establish that a cilium is non-motile?
Answer
Motile embryonic nodal cilia are a counterexample. Arrangement alone does not establish motility.
Card 41
Question
What extra clue would help identify a fiber described only as supporting cell shape?
Answer
Its protein composition or a specific structure it forms. All three major filament systems contribute to cell mechanics.
Card 42
Question
Why is the claim that all intermediate filaments lie in the cytoplasm incorrect?
Answer
Lamins form the nuclear lamina inside the nucleus.
Card 43
Question
In a 9 + 2 axoneme, does the 9 count nine individual microtubules?
Answer
No. It counts nine outer doublets. The central 2 counts two single microtubules.
Card 44
Question
An ATP-powered motor uses either actin or microtubules. What missing information would identify its track?
Answer
The motor family. Myosins use actin; kinesins and dyneins use microtubules. ATP use alone does not distinguish them.
Card 45
Question
What missing detail would distinguish fibers described only as helping animal-cell division?
Answer
The division structure or step. Spindle fibers are microtubules; the contractile ring contains actin.
Card 46
Question
A student says microvilli are miniature cilia because both project from the cell. What core-filament correction is needed?
Answer
Microvilli are supported by actin bundles; cilia have a microtubule-based core. Surface shape alone does not make them the same structure.
Card 47
Question
In microtubule-based transport, how does the filament’s role differ from the motor’s?
Answer
The microtubule supplies a track; kinesin or dynein supplies motor activity.
Card 48
Question
What extra detail is needed to identify a cytoskeletal system described only as enabling cell movement?
Answer
The type of movement. Actin supports crawling; microtubules and dyneins support ciliary or flagellar motion.
Card 49
Question
Is it accurate to say that microtubules have no role in animal-cell cytokinesis because the ring uses actin?
Answer
No. Microtubules also help coordinate cytokinesis, including positioning and organizing the division machinery.
Card 50
Question
Is the cytoskeleton a permanent, unchanging scaffold?
Answer
No. Its filaments and networks can assemble, disassemble, and reorganize as the cell’s needs change.
50 cards
Cytoskeleton Flashcards: Fibers, Motors & Functions
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