13 Answered Questions for the topic biophysics
Are chromosomes soluble when they are condensed?
DNA is soluble, but are chromosomes still dissolved in the aqueous phase when they are condensed during cell division?
What physical forces pull/press water upwards in vegetation?
Each spring enormous amounts of water rise up in trees and other vegetation. What causes this stream upwards? Edit: I was under the impression that capillary action is a key factor: the original... more
Role of microvilli in cell volume regulation?
Does the presence of microvilli on a cell's surface ensure that it's more resistant to cell swelling or lysis in a hypotonic solution, as compared to a normal cell?
How do trees use Adhesion and Cohesion to move water against gravity?
I have an AP Bio class where I have to name 3 properties of water and I chose adhesion and cohesion for one of them. I'm having trouble finding out how exactly trees use adhesion and cohesion to... more
Why don't membrane proteins move?
I understand that based on their tertiary structure, intrinsic proteins have hydrophobic non-polar R-groups on their surface and that they 'interact with the hydrophobic core of the cell membrane... more
Why don't phospholipid bilayers dissolve?
I just started learning about the structure and composition of cell's membrane and there is something that I fail to understand. The membrane is composed of a phospholipid bilayer. The phospholipid... more
What is the difference between organelle membranes?
Cells and organelles are contained in [lipid bilayers](http://en.wikibooks.org/wiki/Structural_Biochemistry/Lipids/Lipid_Bilayer). I'm particularly interested in eukaryotic organelle bilayers and... more
Short of collision, can gravity itself kill you?
Imagine that you are falling into object with huge gravity (i.e. black hole) that does not have any atmosphere. The question is - before you hit the ground, can the gravity itself (which would be... more
How fast can a human run?
I'm a runner (cross country) and I'm always amazed at how fast Olympic sprinters are. There's a lot of hype about those in the 100-meter dash being the fastest in the world, and we're constantly... more
Stretching and compressing bones?
The Young's modulus of elasticity when a bone is stretched is : 16*109 and when it is compressed, it is 9*109 N/m2. That means, change in length will be more if you compress a bone as compared to... more
Why don't dragonflies wings collapse?
How do dragonflies manage to fly at such high speeds without their wings collapsing? Their wings are thinner than paper, but they do not even flutter. What gives them their strength?
How, on a physical level, does ATP confer energy?
When ATP is used as the energy currency to make, say, reaction X + Y → Z happen, is what happens on a physical level down at the molecular scale that during the reaction---**ATP + H2O → ADP + Pi** ... more
Is the EC50 of an activating protein for an enzyme a good indicator for the binding affinity Kd?
We work with a membrane protein system where measuring the affinity between the enzyme and the upstream activating protein has been difficult, and when measured in detergent solution, it is almost... more