hw1 - BE.430J/6.561J/2.795J/10.539J/HST.544J Fall 2004...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BE.430J/6.561J/2.795J/10.539J/HST.544J Fall 2004 Homework 1 Due Wednesday (9/22) by 5pm 1. Oxygen Diffusion in Cells a) Oxygen is consumed by cells at a rate which is often nearly independent of the O 2 concentration. Assume that a cell is a sphere of radius a , and let k 0 and C 0 be the O 2 consumption rate per unit volume and the O 2 concentration just inside the cell membrane, respectively. Derive an expression for the steady-state O 2 concentration profile in the cell, C ( r ), assuming that the consumption rate is spatially uniform. Using the data given below, show that diffusion limitations at the single-cell level are unimportant. 2 Data: D 11 0 5 cm (O 2 diffusivity in cytoplasm) c s m = 0.2 pmol (typical O 2 consumption rate of mammalian cell) c h cell a 10 µ m C 0 = µ M (typical O 2 level in mixed venous blood or tissues) b) Consider now an aggregate of closely packed cells which is a sphere of radius b (>> a ). If b and k 0 are sufficiently large, no O 2
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

hw1 - BE.430J/6.561J/2.795J/10.539J/HST.544J Fall 2004...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online