PCB3134 Exam 4 – Questions With Verifiable Answers
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Terms in this set (308)
Myofibrils are long, thread-like structures within muscle fibers,
What are myofibrils?
divided into repeating units called sarcomeres.
The basic repeating unit of a myofibril, containing bundles of thin
What is a sarcomere?
and thick filaments.
What proteins are found in thick Thick filaments primarily consist of myosin molecules.
filaments?
What proteins are found in thin Thin filaments contain actin, tropomyosin, and troponin.
filaments?
What is the role of tropomyosin Tropomyosin blocks myosin-binding sites on actin filaments,
in muscle contraction? preventing contraction until calcium binds to troponin.
Troponin is a calcium-sensitive protein that, when bound to
What is the function of
calcium, causes tropomyosin to shift and expose myosin-binding
troponin?
sites on actin.
The sliding-filament model explains that muscle contraction
What is the sliding-filament
occurs as thin filaments slide past thick filaments, without
model?
changing their lengths.
What triggers the power stroke The release of inorganic phosphate (Pi) from the myosin head
in muscle contraction? triggers the power stroke.
What is the role of ATP in muscle ATP binds to myosin, causing it to detach from actin and return to
contraction? a high-energy state for another contraction cycle.
How does calcium influence Calcium binds to troponin, causing a conformational change that
muscle contraction? moves tropomyosin and exposes myosin-binding sites on actin.
What are the main types of The main types of junctions are adherens junctions, desmosomes,
junctions found in muscle cells? gap junctions, and tight junctions.
What is the structure of smooth Smooth muscle cells are long and thin with pointed ends and
muscle cells? lack striations, having dense bodies instead of Z lines.
Contraction in smooth muscle is initiated by an increase in
What initiates contraction in
intracellular calcium, which activates myosin light chain kinase
smooth muscle?
(MLCK).
What is the function of myosin Myosin light-chain phosphorylation allows myosin to interact
light-chain phosphorylation? with actin filaments, facilitating contraction.
What happens to calcium levels Calcium levels fall as calcium is pumped out of the sarcoplasm,
after muscle contraction? leading to muscle relaxation.
What are lamellipodia and Lamellipodia are thin sheets of cytoplasm, while filopodia are
filopodia? thin, pointed protrusions that help cells crawl over substrates.
, What is the role of structural Structural proteins maintain the architecture of muscle cells, such
proteins in muscle cells? as α-actinin, CapZ, and titin.
What is the significance of titin in Titin connects thick filaments to Z lines, providing elasticity and
muscle cells? structural support to muscle cells.
The T tubule system transmits nerve impulses into the muscle cell,
What is the function of the
facilitating the release of calcium from the sarcoplasmic
transverse (T) tubule system?
reticulum.
What is the role of calcium Calcium pumps in the sarcoplasmic reticulum help regulate
pumps in muscle cells? calcium levels, crucial for muscle contraction and relaxation.
What are the key differences Smooth muscle is involuntary, slower, and lacks striations, while
between smooth muscle and skeletal muscle is voluntary, faster, and striated.
skeletal muscle?
What is the function of Intermediate filaments connect dense bodies in smooth muscle,
intermediate filaments in smooth contributing to structural integrity.
muscle?
What is the role of Rho, Rac, and These G proteins are involved in the formation of lamellipodia,
Cdc42 in cell protrusion? filopodia, and stress fibers during cell movement.
What occurs during the cross- The cross-bridge cycle involves the formation and dissociation
bridge cycle? of links between actin and myosin, leading to muscle contraction.
What are the two types of Lamellipodia (thin sheet of cytoplasm) and filopodia (thin-
protrusions that cells extend at pointed protrusion).
their leading edge?
Which G proteins are involved in Rho (stress fibers), Rac (lamellipodia), Cdc42 (filopodia).
the formation of lamellipodia,
filopodia, and stress fibers?
It is the movement of microfilaments toward the rear of the
What is retrograde flow in cell
protrusion as it extends, driven by actin assembly and myosin-
protrusions?
powered translocation.
What drives actin Arp2/3-dependent branching.
polymerization in lamellipodia?
Integrins are transmembrane proteins that attach cells to
What are integrins and their role
extracellular matrix proteins and connect to actin filaments inside
in cell attachment?
the cell.
Integrin-dependent attachments between cells and the
What are focal adhesions?
extracellular matrix.
Contraction at the rear of the cell squeezes the cell body
How does cell contraction
forward and releases attachments at the rear, controlled by Rho
facilitate movement?
activating nonmuscle myosin II.
What are the main types of Epithelium (polarized sheets of cells) and connective tissue
tissues in animals? (loosely organized with cells attached to a scaffold).
Structures where two cells come together to form tissues and
What are cell-cell junctions?
organs.
Name the common types of Adherens junctions, tight junctions, gap junctions, and
cell-cell junctions in animal cells. desmosomes.
What are plasmodesmata? Cell-cell junctions found in plant cells.
What are the two types of cell- Focal adhesions and hemidesmosomes.
ECM junctions?
What is the function of adherens To mediate cell-cell adhesion through cadherins and link to the
junctions? actin cytoskeleton.
Adhesion proteins that mediate cell-cell adhesion and are
What are cadherins?
characterized by repeats in their extracellular domain.
The best characterized cadherin, known for its role in epithelial
What is E-cadherin?
cell adhesion.
Save
Students also studied
INBDE Orthodontics NBDE II Review - Prosthodontics Perio Study
201 terms 69 terms Teacher 78 terms
dong_lee82 Preview melissa_jarvis7 Preview Hunter_Charters
Terms in this set (308)
Myofibrils are long, thread-like structures within muscle fibers,
What are myofibrils?
divided into repeating units called sarcomeres.
The basic repeating unit of a myofibril, containing bundles of thin
What is a sarcomere?
and thick filaments.
What proteins are found in thick Thick filaments primarily consist of myosin molecules.
filaments?
What proteins are found in thin Thin filaments contain actin, tropomyosin, and troponin.
filaments?
What is the role of tropomyosin Tropomyosin blocks myosin-binding sites on actin filaments,
in muscle contraction? preventing contraction until calcium binds to troponin.
Troponin is a calcium-sensitive protein that, when bound to
What is the function of
calcium, causes tropomyosin to shift and expose myosin-binding
troponin?
sites on actin.
The sliding-filament model explains that muscle contraction
What is the sliding-filament
occurs as thin filaments slide past thick filaments, without
model?
changing their lengths.
What triggers the power stroke The release of inorganic phosphate (Pi) from the myosin head
in muscle contraction? triggers the power stroke.
What is the role of ATP in muscle ATP binds to myosin, causing it to detach from actin and return to
contraction? a high-energy state for another contraction cycle.
How does calcium influence Calcium binds to troponin, causing a conformational change that
muscle contraction? moves tropomyosin and exposes myosin-binding sites on actin.
What are the main types of The main types of junctions are adherens junctions, desmosomes,
junctions found in muscle cells? gap junctions, and tight junctions.
What is the structure of smooth Smooth muscle cells are long and thin with pointed ends and
muscle cells? lack striations, having dense bodies instead of Z lines.
Contraction in smooth muscle is initiated by an increase in
What initiates contraction in
intracellular calcium, which activates myosin light chain kinase
smooth muscle?
(MLCK).
What is the function of myosin Myosin light-chain phosphorylation allows myosin to interact
light-chain phosphorylation? with actin filaments, facilitating contraction.
What happens to calcium levels Calcium levels fall as calcium is pumped out of the sarcoplasm,
after muscle contraction? leading to muscle relaxation.
What are lamellipodia and Lamellipodia are thin sheets of cytoplasm, while filopodia are
filopodia? thin, pointed protrusions that help cells crawl over substrates.
, What is the role of structural Structural proteins maintain the architecture of muscle cells, such
proteins in muscle cells? as α-actinin, CapZ, and titin.
What is the significance of titin in Titin connects thick filaments to Z lines, providing elasticity and
muscle cells? structural support to muscle cells.
The T tubule system transmits nerve impulses into the muscle cell,
What is the function of the
facilitating the release of calcium from the sarcoplasmic
transverse (T) tubule system?
reticulum.
What is the role of calcium Calcium pumps in the sarcoplasmic reticulum help regulate
pumps in muscle cells? calcium levels, crucial for muscle contraction and relaxation.
What are the key differences Smooth muscle is involuntary, slower, and lacks striations, while
between smooth muscle and skeletal muscle is voluntary, faster, and striated.
skeletal muscle?
What is the function of Intermediate filaments connect dense bodies in smooth muscle,
intermediate filaments in smooth contributing to structural integrity.
muscle?
What is the role of Rho, Rac, and These G proteins are involved in the formation of lamellipodia,
Cdc42 in cell protrusion? filopodia, and stress fibers during cell movement.
What occurs during the cross- The cross-bridge cycle involves the formation and dissociation
bridge cycle? of links between actin and myosin, leading to muscle contraction.
What are the two types of Lamellipodia (thin sheet of cytoplasm) and filopodia (thin-
protrusions that cells extend at pointed protrusion).
their leading edge?
Which G proteins are involved in Rho (stress fibers), Rac (lamellipodia), Cdc42 (filopodia).
the formation of lamellipodia,
filopodia, and stress fibers?
It is the movement of microfilaments toward the rear of the
What is retrograde flow in cell
protrusion as it extends, driven by actin assembly and myosin-
protrusions?
powered translocation.
What drives actin Arp2/3-dependent branching.
polymerization in lamellipodia?
Integrins are transmembrane proteins that attach cells to
What are integrins and their role
extracellular matrix proteins and connect to actin filaments inside
in cell attachment?
the cell.
Integrin-dependent attachments between cells and the
What are focal adhesions?
extracellular matrix.
Contraction at the rear of the cell squeezes the cell body
How does cell contraction
forward and releases attachments at the rear, controlled by Rho
facilitate movement?
activating nonmuscle myosin II.
What are the main types of Epithelium (polarized sheets of cells) and connective tissue
tissues in animals? (loosely organized with cells attached to a scaffold).
Structures where two cells come together to form tissues and
What are cell-cell junctions?
organs.
Name the common types of Adherens junctions, tight junctions, gap junctions, and
cell-cell junctions in animal cells. desmosomes.
What are plasmodesmata? Cell-cell junctions found in plant cells.
What are the two types of cell- Focal adhesions and hemidesmosomes.
ECM junctions?
What is the function of adherens To mediate cell-cell adhesion through cadherins and link to the
junctions? actin cytoskeleton.
Adhesion proteins that mediate cell-cell adhesion and are
What are cadherins?
characterized by repeats in their extracellular domain.
The best characterized cadherin, known for its role in epithelial
What is E-cadherin?
cell adhesion.
