3 (5 points). You plan to grow your Chlamydomonas in the dark because you think

ID: 149293 • Letter: 3

Question

3 (5 points). You plan to grow your Chlamydomonas in the dark because you think that triacylglycerols are synthesized in higher amounts under this condition. You plan to give your culture glucose as a carbon source. You plan to add 5 mM glucose to your culture, which is 50 mL. You think you should ask the prep lab to prepare a 1 M solution, but they want to know how many grams to add to how many mL to make your stock. You decide to ask for 200 mL of the 1 M stock. How much glucose (in g) should you ask them to prep in 200 mL, and how much of it would you add to your culture for your 5 mM concentration? 4 (5 points). You want to prepare a mineral salts medium that contains (per Liter) 5 g glucose 0.68 g KH2PO 1.73 g K2HPO 0.1 g MgSO, 7H20 4 g NaCI 0.03 g FeSO 7H,O 1 g NH,NO, 0.02 g CaCI, The prep lab has asked that for any medium you want prepared, if you are going to store it in the lab, you should prepare a Right To Know label. The rules for this are that you need to list the top 5 ingredients by percentage in your medium (remember that you're making it in water!), you should include the CAS number (this is a registry number for any chemical), and you should also write the name of the chemical out fully, not the chemical abbreviation, so that if someone who does not know that CaC12 is calcium chloride, for instance, they have the full name. For the above medium, what would a label look like?

Explanation / Answer

Q3:

Mol massof glucose is 180.15 g/mol

=> 180.15g of glucose in 1000mL= 1M

=> for 200mL: (200/1000)*180.15 = 36.03

To prepare 200mL of 1M glucose solution add 36.03g of glucose in about 100mL of water, dissolve completely and make up to 200mL final volume.

Since the culture volume is 50 mL we can use the molar equivalence equation to find out how much stock to add as follows:

Required final concentration (M1) = 5mM

Final volume (V1) = 50mL

Stock concentration (M2) = 1M = 1000mM

Required stock volume (V2) = ???

Since, M1 X V1 = M2 X V2

V2 = (M1 X V1)/ M2

= (5*50)/1000

= 0.25 mL

The volume of 1M stock to add to 50mL media is 0.25mL

Q5) Find answer tabulated

CAS#

CHEMICAL FORMULA

CHEMICAL NAME

g/L Weight

Percentage in solution

50-99-7

C6H12O6

Glucose

0.5

7647-14-5

NaCl

Sodium Chloride

0.4

7758-11-4

K2HPO4

Dipotassium hydrogen phosphate

1.73

0.17

6484-52-2

NH4NO3

Ammonium nitrate

0.1

7778-77-0

KH2PO4

Potassium Dihydrogen phosphate

0.68

0.07