Lecture 5 Flashcards
Functions of Cytoskeleton
- Support cell
- Maintain shape
- Anchor points for organelles and proteins
- Move structures within cell
- Cells move by dismantling and rebuilding
cytoskeleton
Microtubules
- Largest component of cytoskeleton
- Grow from centrosome and centrioles
(animal cells) - Move chromosomes during cell division
- Guide movement of transport vesicles
Motor Proteins
- Energy from ATP
used to change the
shape of motor
protein - Causes motor
proteins to “walk”
along microtubules - Moves organelles
within cell - Changes shape of
the cell membrane
Cilia and Flagella
- Structurally similar
- Flagella longer and fewer in number
- Movement of cell
– Paramecium (cilia)
– Sperm (flagellum) - Movement of extracellular fluid
– Mucus layer in trachea (cilia)
– Water circulation in sponges (flagella)
Microfilaments
- Smallest component
of cytoskeleton - Chain of actin subunits
- Often form network inside cell membrane
– Maintain cell shape
Microfilaments often interact with…
Larger myosin filaments
– Type of motor protein
– Responsible for muscle contractions
Myosin
- Myosin interactions also
involved in cytoplasmic
streaming
– Flow of cytoplasm - Myosin connects
organelles to
microfilaments - Myosin and actin create
intracellular contractions
Intermediate Filaments
- Only in cells of some animals
- Variety of proteins
- Permanent framework for cell, especially
nucleus
molecule required by cells to assemble Cilia and Flagella
tubulin
The activation of receptor tyrosine kinases is characterized by
dimerization and phosphorylation.
What is the function of receptor tyrosine kinases?
enzymatic phosphorylation of tyrosine in the receptor protein
Sequence of the signal transduction pathway that utilizes a G protein-coupled receptor
A signal molecule binds to a receptor.
The signal-receptor complex activates a G protein.
cAMP is produced.
Protein kinases are activated
Target proteins are phosphorylated.
Amoeboid
– Cytoplasmic streaming and pseudopodia
