Animal Cells (Part Five) Flashcards
What is the grouping of intermediate filament types based on?
- central rod domain amino acid sequences
- net acidic charge
- secondary structure
What is the general function of intermediate filaments?
- providing mechanical strength
- organising cytoplasmic architecture
- signalling
- regulating transcription
What are intermediate filaments composed of?
A broad range of different coiled-coil protein subunits
True or False:
Intermediate filaments are found in all organisms.
FALSE.
Intermediate filaments are only found in animal cells.
Describe the assembly of intermediate filaments
Self-assemble into an apolar filament.
Do not require ATP or GTP for assembly.
What forms the nuclear lamina?
Intermediate filaments
What is the role of lamina?
- provide stability
- organise the nucleus
Why might intermediate filaments disassemble into subunits?
To allow cell movement
How many different intermediate filaments participate in development and function of the vertebrate eye lens?
7
Describe the role of intermediate filaments in the eye lens.
- Determine the optical properties of the eye lens
- Critical to lens transparency
Name the three molecular motors.
- Dyenin
- Kinesin
- Myosin
Which molecular motors are microtubule-associated?
- Dyenin
- Kinesin
Which molecular motor is actin-associated?
Myosin
Which molecular motor is the longest?
Myosin
Which molecular motor has the largest motor domains?
Dyenin
What is the role of
a) Myosin II?
b) Myosin V?
a) Myosin II = muscle myosin
b) Myosin V = membrane trafficking
Towards which end of the microtubule do the following molecular motors move:
a) Kinesin?
b) Dyenin?
a) Kinesin = towards the ‘plus’ end
b) Dyenin = towards the ‘minus’ end
Describe how dyenin and kinesin move differently to avoid collisions.
- Dyenin ‘dances’ on the microtubule, using several protofilaments.
- Kinesin stays on the same protofilament and ‘walks’ in a straight line.
What shapes the endoplasmic reticulum?
Molecular motors
How long would an average organelle, 1 micrometer in diameter, take to diffuse 30cm?
21 thousand years
What is meant by
a) Anterograde transport?
b) Retrograde transport?
a) Anterograde transport = Minus to plus end (e.g. cell body to synapse)
b) Retrograde transport = Plus to minus end (e.g. synapse to cell body)
What percentage of your body is muscle?
40%
What percentage of your muscle is
a) Protein?
b) Actin?
a) Protein = 20%
b) Actin = 12-15%
What are the units of structure within a muscle called?
Sarcomeres
