Proteins and carbohydrates 5 Flashcards
Describe the properties of the fluid within which motor proteins operate.
High viscous drag dominates inertia so relatively high amount of energy input is required constantly for sustaining movement.
How was the rectified-diffusion model proved to be wrong in explaining the motion of motor proteins?
The rectified-diffusion model implies that the maximum force that motor proteins can resist is 1pN. Kinesin have been observed to resist loads significantly higher than 1pN.
How was the flashing ratchet model proved to be wrong in explaining the motion of motor proteins?
It implied that 2 ATP are required per motor movement step but experiments demonstrate that only 1 ATP is consumed per 8nm of motion.
How was the thermal ratchet model proved to be wrong in explaining the motion of motor proteins?
It implies that the distance to the transition state from the intial state is longer than it has been found to be.
What is the powerstroke model?
It is a model used to understand the movement of motor proteins.
State some functions of carbohydrates.
Energy storage (e.g. glycogen),
Structural elements (e.g. cartilage),
Cell-cell recognition and adhesion (cells have proteins on their surface that bind to specific carbohydrates).
What are carbohydrates also known as?
Saccharides
What are the basic building blocks of carbohydrates (like amino acids to proteins) called?
Monosaccharides (a.k.a. simple sugars)
What are the 2 types of monosacchoride?
Furanoses (contain a 5 membered ring) and pyranoses (contain a 6 membered ring).
What is an an enantiomer?
A mirror image molecule of a molecule. Where the positions of all OH groups or other side groups have been flipped with their respective H atoms connecting to their shared carbon atoms on the ring.
What is an epimer of a molecule?
A molecule that differs from the original by swapping the position of only one of the OH or other side groups of a molecule with a H in the molecule.
Why can pyranoses form different-shaped structures?
The 6-membered ring of pyranoses is not planar/flat. There are steric constraints in the ring which makes the ring form a 3D structure.
What type of bond connects monosaccharides together?
Glycosidic linkages/bonds (sharing an oxygen atom and producing a water molecule).
Can the WLC model be used to model the mechanical stability of polysaccharides?
At small forces, polysaccharides are entropically elastic chains and follow the WLC model.
