Lecture 11 Cytoskeleton and Energy Flashcards
cytoskeleton
- system of filaments
- dynamic and adaptable
- shape, structure, robustness, rearranging of internal components, movement, growth, division
- examples: swimming of sperm, structure of the membrane, vesicular traffic, pulling of chromosomes during the division (moving of things around, in the cell)
3 different protein groups, which make 3 different type of filaments:
actin filaments (microfilaments) microtubules intermediate filaments
actin filaments
- microfilaments
- 2 stranded helical structure
- polymer of protein actin
- networks mostly concentrated under the plasma membrane
Microtubules
- long hollow cylinders
- made of protein tubulin
- long, rigid, strait
- attached at one end to the centrosom
Intermediate filaments
ropelike fibers family of proteins (nuclear lamina) (strength of tissue)
Actin filaments rearrangement can be used to …
make cells move
Cell division: interplay of microtubules and actin filaments
Actin: ring construction
microtubules: pulling chromosomes
How microtubules pull chromosomes?
By shrinking at one end
How to kill a rapidly dividing cell (cancer cell)?
Stabilization of microtubules (including the mitotic spindle) by taxol
Requirements for efficient ATP production
membranes
transferring of electrons
proton gradient
Mitochondria
Thanks to mitochondria, more complex eukaryal cells (Metazoa), could develop. Mitochondria allow cells to produce 15 times more ATP per unit of glucose or fat. Mitochondria localize with microtubules. They are dynamic, fusing, branching, fragmenting and changing shape and position in the cell. Mitochondria have circular genomes, their proteins are encoded by the nuclear DNA and mtDNA.
Electrons produced in the … are being carried around in the mitochondrion and the end result is the production of …
TCA (citric acid cylce)
ATP, CO2 and H2O
Biological oxidation extracts the energy …
step-wise
Electron-driven pumps export protons, on their return protons drive the …
ATP synthesis
How does the electron transfer work?
- NADH -> NAD+, 1 proton H+ and 2 electrons e-
- electron carriers, eg NAD+, (metal ions), electrons loose energy
- three respiratory enzyme complexes
- The terminal acceptor of electrons is O2
NADH dehydrogenase complex
passes 2 electrons from NADH to ubiquinone
Cytochrome c reductase complex
receives 1 electron from ubiquinol
passes the electron to cytochrome C oxidase
Cytochrome oxidase complex
receives 1 electron from the cytochrome C the last complex receives 1 electron at the time and ”collects” them before donating 4 electrons to O2 (forming H20)
Pumping of protons to the intermembrane space creates a … and …
pH gradient
a voltage gradient (electric potential).
Th e protons are on the outer side of the inner membrane. The gradient transfers them back to the matrix. But, they will go via the …
F0F1 ATP-synthase
Rotary catalysis
flow of protons changes the conformations of subunits, creating mechanical energy that is then converted to chemical energy during the formation of the phosphate bond: 3 ATP/rotation
Inhibition of ATP production and thermogenesis
thermal energy instead of ATP production
