Cell moltility and the cytoskeleton Flashcards
from Alistairs question booklet - theme 1
- Actin
a. is made up of subunits of F-actin
b. can be polymerised to form microtubules
c. is made up of two types of subunit: F-actin and G-actin
d. is a double helix
e. is a triple helix
d
a. Actin is made up of subunits called G-actin, which polymerize to form F-actin filaments. So, while F-actin does exist, it’s not made up of F-actin subunits.
b. Actin does not polymerize to form microtubules. Microtubules are formed from tubulin protein subunits, not actin.
c. Actin is primarily composed of G-actin subunits, which polymerize to form F-actin filaments. There’s no separate category of subunit called G-actin and F-actin within actin itself.
e. Actin does not form a triple helix. Triple helix structures are more commonly associated with collagen, not actin.
Polymerisation of actin filaments
a. occurs more quickly at the minus end of actin
b. occurs when the subunit is bound to ADP
c. is irreversible
d. can only occur at the plus end of actin
e. requires ATP to be bound to the actin subunit
e
The actin binding protein transgelin is
a. a severing protein
b. a cross-linking protein
c. an actin bundling protein
d. a side-binding protein
e. a capping protein
b
An example of an actin-sequestering protein is
a. profilin
b. alpha-actinin
c. myosin
d. gelsolin
e. spectrin
a
The following is not a type of intermediate filament:
a. keratin
b. vimentin
c. neurofilamin
d. spectrin
e. glial fibrillary acidic protein
d
Axons lacking intermediate filaments are
a. reduced in diameter
b. increased in diameter
c. increased in length
d. reduced in length
e. cannot form at all
a
Microvilli are supported by
a. single microtubules
b. single actin filaments
c. intermediate filaments and microtubules
d. bundles of actin filaments
e. bundles of intermediate filaments
d
Microtubules maintain the organisation of the
a. nucleus
b. endoplasmic reticulum
c. cell membrane
d. mitochondria
e. centrosomes
b
Cell movement can occur when
a. intermediate filaments polymerise and depolymerise rapidly
b. actin filaments polymerise and depolymerise rapidly
c. microtubules are sent out from the centrosome
d. the cytoskeleton breaks down
e. protrusion filaments form within the cell
b
Lamellipodia
a. are a type of protein that form ‘cell fingers’
b. are exploratory processes formed by actin and integrins
c. are ‘cell feet’ formed by intermediate filaments and spectrin
d. allow cells to contact other cells for signal transduction
e. are processes that surround a pathogen prior to phagocytosis
b
NOT A BECUASE . Lamellipodia are not proteins themselves but rather dynamic structures within cells. They are not referred to as “cell fingers.”
Actin and myosin cause movement because
a. actin pulls on myosin
b. myosin pulls on actin
c. myosin moves continuously down actin
d. myosin attracts actin chemotactically
e. actin changes conformation when bound to myosin
B
Cilia movements are associated with
a. actin and myosin
b. myosin and microtubules
c. microtubules and dynein
d. microtubules and kinesin
e. actin and kinesin
c
The mechanism of colchicine in preventing cell division is
a. to destabilise actin binding
b. to inhibit intermediate filament formation around the nucleus
c. to inhibit centrosome formation
d. to destabilise microtubules
e. to alter gene regulation
d
An example of an intermediate filament disease is
a. Duchenne muscular dystrophy
b. Becker muscular dystrophy
c. Epidermolysis bullosa symplex
d. Alzheimer’s disease
e. Hereditary spastic paraplegia
c
