AN EQUATION FOR THIS PROBLEM

a DEEP SPACE PROBE IS TRAVELING AT A VELOCITY OF 18.8KM/S. WHAT IS IT VELOCITY IN MILES/MINUTES? ASTRONOMERS HAVE MEASURED A FAINT GALAXY TO BE AT DISTANCE OF 200 MEGAPARSECS FROM EARTH. hOW FAR IS THIS IN MILES?(1PARASEC=3.26LIGHT-YEARS, MEGA=1X10 TO THE SIXTH POWER). A PERFUME COMPANY WANTS TO DESPENSE 13.9 QUARTS OF A NEW FRAGARANCE INTO SMALL VIALS. HOW MANY 25.ML VIALS CAN THEY FILL? AN EON OF TIME IS DEFINED AS 1 BILLION YEARS (1X10TO THE NINTH POWER YEARS). HOW LONG IS THIS IN SECONDS? ASSUME ONE YEAR IS EQUAL TO 365.25DAYS.

GRE Subject Biochem problem (Chromatography Elution)

Sketch the expected chromatographic elution profile (protein concentration vs elution volume) if a mixture of these proteins is applied to a weak anion exchange resin such as DEAE-cellulose at pH 7. Label and show the salt gradient used for elution Sketch the expected chromatographic elution profile (protein concentration vs elution volume) if a mixture of these proteins is applied to a weak cation exchange resin such as CM-cellulose at pH 7. Label and show the salt gradient used for elution Protein; (A ), pI 8, MW 25000 (B) , pI 10, MW 10000 C , pI 4 , MW 70000 D , pI 6, MW 5000

Biophysics -Calculating ^G (^=delta)

In one day the average person secretes about 2.5 litres of gastric juice into the stomach. The pH of the cells in the stomach lining that perform the secretion is about 7 (the same as for all cells) and the pH of the stomach is about 1. Thus, H+ ions must be moved against an H+ gradient. The free energy change for moving molecules against a gradient is: ^G = R T lne(C2/C1) (where ^ = delta) where C2 is the greater concentration. If the process of pumping H+ ions is 20% efficient, how many moles of ATP are used each day to secrete gastric juice? How many kilograms could be lifted one meter (20% efficiency) wiht this energy?

GRE Biochem Question (Ligand Binding)

Plot the following data using a Sacatchard type plot. The change in fluorscence is proportional to binding. A) Determine the max binding constant for the protein complex Realtive Fluorescence (Response) [Protein] nM (concentration of added protein) 5.70E+04 0 5.73E+04 0.1 5.78E+04 0.3 5.89E+04 1 6.03E+04 3 6.13E+04 10 6.17E+04 30 6.18E+04 50

GRE Subject Question

How many different primary sequences are possible for a pentapeptide made from natrually occurring amino acids? Considering that most proteins are composed of one hundred or more what conclusions can be drawn from the calculation?