Cytoskeleton Flashcards
3 major functions of the cytoskeleton
Movement, structural support, cell shape
What are microfilaments made of?
Actin
In what cells are intermediate filaments found?
Animal cells
Which of microfilament, intermediate filaments and microtubules are polar?
microfilaments and microtubules
What functions do intermediate filaments provide?
structural support + maintenance of cell and nucleus shape
What do intermediate filaments lack that the other 2 have?
Motor proteins
What is tubulin?
An alpha-beta heterodimer protein
How many protofilaments make up microtubules?
13
Is alpha or beta tubulin at plus end of microtubule?
beta as can hydrolyse GTP so is more dynamic
What is importance of GTP cap?
Stops dissociation of protofilaments and allows new subunits to join
When do microtubules grow?
When polymeristaion rate exceeds hydrolysis
What does gamma tubulin bind to?
Alpha tubulin and intracellular organnelles
Where microtubules originate from in interphase animal cells?
Centrosome
Why is microtubule dynamic instability important?
provides a way for cell to explore and sense changes
How much does 1x 8nm kinesin step cost?
1 ATP
How many more times rigid are microtubles than microfilaments?
150
What is the name fro the part of cilia that extrudes from the cell?
Axoneme
What protein complex has 3 motor heads and causes motion waveform in cilia?
Ciliary dynein
What are the 2 functions of cilia and flagella?
motility and sensing
Length and number of monomers in actin microfilament helix repeat
37nm and 13 monomers
What is term used for Actin dynamics?
Treadmilling
Primary function of actin microfilaments in plants ad fungi?
pathway for organelle movement
Primary function of actin microfilaments in animals?
cell shape and motility
What motor proteins are used in plants on actin filaments?
Myosin
Name for dramatic conformational change during myosin walking?
Power stroke
What do actin and myosin-II form IN ANIMALS?
Contractile arrays
What causes cytokinesis?
Contracile ring- actin and myosin II
What are most developmental genes involved in?
control of transcription and intercellular signalling
What are the devlopmental toolkit genes?
Hox, MyoD, FGF, Wnt, Bmp
Hat does Wnt control in devlopment?
AP axis (cniderian- aboral-oral axis)
What is interesting about Bmp between deuterosomes and protosomes?
DV axis inversion- nervous system on opposing sides
What is colinearity?
order of genes in cluster on chromosome same as order of expression along axis
Give an example of colinearity
HOX genes
What is tandem duplication?
another copy of gene next to original on chromosome
What is the homeodomain?
DNA binding domain HOX genes have
