Conversion + Stoichiometry

C3​H8​ + 5O2 ​→ 3CO2 ​+ 4H2​O

How many grams of CO₂ (MM = 44 g/mol) can be produced if 2.2 g of C₃H₈ (MM = 44 g/mol) is completely combusted?

A solution of NaCl has a concentration of 2 M. How many mmol of NaCl are present in 250 mL of this solution?

How many μmol of glucose in 0.09 g sample of glucose (MM = 180g/mol)?

3Ca2+ + 2PO43−​ → Ca3​(PO4​)2​

A researcher has 400 mL of a 3 M Ca²⁺ solution. How many moles of PO₄³⁻ are needed to fully react all of the Ca²⁺?

Activation of RhoA occurs when two GTP molecules coordinate with one Mg2+ cofactor in the protein’s binding domain. To investigate how testosterone impacts RhoA activation in certain cancers HEK293 cells were transfected with GPR56 and incubated with 1 μL testosterone (10 nM). The cells were then lysed in 300 μL of a lysis buffer (50 mM Tris p H 7.5, 10 mM MgCl2 0.5 M NaCl and 2% Igepal) and centrifuged. 200 μL of supernatant was incubated with 30 μg of rhotekin beads to pull down active RhoA and detected using anti-RhoA mAb. 

How many nmol of testosterone were added to the cells when studying RhoA activation?

Activation of RhoA occurs when two GTP molecules coordinate with one Mg2+ cofactor in the protein’s binding domain. To investigate how testosterone impacts RhoA activation in certain cancers HEK293 cells were transfected with GPR56 and incubated with 1 μL testosterone (10 nM). The cells were then lysed in 300 μL of a lysis buffer (50 mM Tris p H 7.5, 10 mM MgCl2 0.5 M NaCl and 2% Igepal) and centrifuged. 200 μL of supernatant was incubated with 30 μg of rhotekin beads to pull down active RhoA and detected using anti-RhoA mAb. 

If the Mg²⁺ concentration in the lysis buffer reflects the physiological concentration available to RhoA’s active site, how many nmol of GTP are required to fully activate all available Mg²⁺ in the 300 μL lysis buffer?