# Recent questions tagged biochemistry

1
A solution was prepared by dissolving $\text{100 mg}$ of protein $X$ in $\text{100 ml}$ of water. Molecular weight of protein $X$ is $\text{15,000 Da};$ Avogadro’s number = $6.022\times 10^{23}$. The number of molecules present in this solution is $40.15\times10^{19}$ $6.023\times10^{19}$ $4.015\times10^{19}$ $0.08\times10^{19}$
2
In a chemostat, the feed flow rate and culture volume are $100$ ml/h and $1.0$ L, respectively. With glucose as substrate, the values of $\mu_{\text{max}}$ and $K_s$ are $0.2 \: h^{-1}$ and $1 \: g/L$, respectively. For a glucose concentration of $10 \: g/L$ in the feed, the effluent substrate concentration (in $g/L$) is _______
3
Yeast converts glucose to ethanol and carbon dioxide by glycolysis as per the following reaction: $C_6H_{12}O_6 \to 2C_2H_5OH + 2CO_2$Assuming complete conversion, the amount of ethanol produced (in $g$) from $200 \: g$ of glucose is (up to two decimal places) ____________
4
First order deactivation rate constants for soluble and immobilized amyloglucosidase enzyme are $0.03 \text{ min}^{-1}$ and $0.005 \text{ min}^{-1}$, respectively. The ratio of half-life of the immobilized enzyme to that of the soluble enzyme is (rounded off to the nearest integer) ___________
5
Consider a simple uni-substrate enzyme that follows Michaelis-Menten kinetics. When the enzyme catalyzed reaction was carried out in the presence of $10$ nM concentration of an inhibitor, there was no change in the maximal velocity. However. the slope of the Lineweaver-Burk plot increased $3$-fold. The dissociation constant for the enzyme-inhibitor complex (in nM) is ____________
A rod shaped bacterium has a length of $2 \: \mu m$, diameter of $1 \mu m$ and density the same as that of water. If proteins constitute $15 \%$ of the cell mass and the average protein has a mass of $50$ kDa, the number of proteins in the cell is __________ ($1$ Da $= 1.6 \times 10^{-24}$g)