Recent questions without answers

Which set of the following events occurs during the elongation step of translation?Attachment of mRNA with the smaller subunit of ribosomeLoading of correct aminoacyl-tRN...

A DNA sequence, $\textrm{5’ -ATGGACGTGCTTCCCAAAGCATCGGGC- 3’}$, is mutated to obtain$\textrm{5'-ATGGACGTGCTTC}\textbf{a}\textrm{CAAAGCATCGGGC- 3'}$$\textrm{5'-ATGGACGTGCT...

Which of the following events occur during the stationary phase of bacterial growth?Rise in cell number stopsSpore formation in some Gram-positive bacteria such as Bacill...

Select the CORRECT combination of genetic components that are essential for the transfer of T-DNA segment from Agrobacterium tumefaciens to plant cells.Border repeat sequ...

Match the secondary metabolites (Column-I) with the corresponding plant species (Column-II).$\begin{array}{|l|l|l|l|} \hline & \textbf{Column-I} & &\textbf{Column-II} \\ ...

A variety of genetic elements are used in the transgenic plant research. Match the genetic elements (Column-I) with their corresponding source (Column-ll).$\begin{array}{...

Match the type of chromosomal inheritance (Column-I) with the corresponding genetic disease or trait (Column-II).$\begin{array}{|l|l|l|l|} \hline & \textbf{Column-I} & & ...

A crossing was performed between the genotypes $\textit{DdEeFfgg}$ and $\textit{ddEeFfGg}$. Assuming that the allelic pairs of all genes assort independently, the proport...

The equilibrium potential of a biological membrane for $Na^+$ is $55$ mV at $37^\circ$ C. Concentration of $Na^+$ inside the cell is $20$ mM. Assuming the membrane is per...

A $1.2$ kb DNA fragment was cloned into $\textit{Bam}$HI and $\textit{Eco}$RI sites located on a $2.8$ kb cloning vector. The $\textit{Bam}$HI and $\textit{Eco}$RI sites ...

Find the INCORRECT combinationSurface immunoglobulins – B cell antigen receptorAffinity maturation - isotype switchingFc region of antibodies – binding to complement prot...

Which of the following statement(s) is/are CORRECT for antigen activated effector T cells?$CD4^+$ cells make contact with macrophages and stimulate their microbicidal act...

Which one of the following statements regarding G proteins is INCORRECT?GDP is bound to G protein in the resting stageGTP bound $\alpha$ subunit cannot reassemble with $\...

In animal cell culture, a CO$_2$ enriched atmosphere in the incubator chamber is used to maintain the culture pH between $6.9$ and $7.4$. Which one of the following state...

Choose the CORRECT combination of True (T) and False (F) statements about microcarriers used in animal cell culture.Higher cell densities can be achieved using microcarri...

In an assay of the type II dehydroquinase of molecular mass $18$ kDa, it is found that the $V_{\text{max}}$ of the enzyme is $0.0134 \: \mu \text{ mol} \cdot \text{min}^{...

The molar extinction coeffcients of Trp and Tyr at $280$ nm are $5690$ and $1280 \: M^{-1} \cdot cm^{-1}$, respectively. The polypeptide chain of yeast alcohol dehydrogen...

The activity of lactate dehydrogenase can be measured by monitoring the following reaction: $$\text{Pyruvate} + \text{NADH} \rightarrow \text{Lactate} + \text{NAD}^+$$ Th...

Analysis of a hexapeptide using enzymatic cleavage reveals the following result:Amino acid composition of the peptide is: $2R, A, V, S, Y$Trypsin digestion yields two fra...

The empirical formula for biomass of an unknown organism is $CH_{1.8}O_{0.5}N_{0.2}$. To grow this organism, ethanol $(C_2H_5OH)$ and ammonia are used as carbon and nitro...

$\textit{Saccharomyces cerevisiae}$ is cultured in a chemostat (continuous fermentation) at a dilution rate of $0.5 \: h^{-1}$. The feed substrate concentration is $10 \:...

Decimal reduction time of bacterial spores is $23$ min at $121 ^\circ C$ and the death kinetics follow first order. One liter medium containing $10^5$ spores per $mL$ was...

A bioreactor is scaled up based on equal impeller tip speed. Consider the following parameters for small and large bioreactors: $$\begin{array}{|l|l|l|l|} \hline \textbf...

An enzyme converts substrate $A$ to product $B$. At a given liquid feed stream of o rate $25$ L.min$^{-1}$ and feed substrate concentration of $2$ mol.L$^{-1}$, the volum...

A protein is to be purified using ion-exchange column chromatography. The relationship between HETP (Height Equivalent to Theoretical Plate) and the linear liquid velocit...

An enzyme is immobilized on the surface of a non-porous spherical particle of $2$ mm diameter. The immobilized enzyme is suspended in a solution having bulk substrate con...

$\dfrac{d^2y}{dx^2}-y=0$. The conditions for this second order homogeneous differential equation are $y(0)=1$ and $\dfrac{dy}{dx}=3$ at $x=0$. The value of $y$ when $x = ...

The value of determinant $A$ given below is ________.$A = \begin{pmatrix} 5 & 16 & 81 \\ 0 & 2 & 2 \\ 0 & 0 & 16 \end{pmatrix}$

Consider the equation$V=\dfrac{aS}{b+S+\dfrac{S^2}{c}}$Given $a = 4$, $b = 1$ and $c = 9$, the positive value of $S$ at which $V$ is maximum, will be _________

An enzyme catalyzes a reaction bydecreasing the energy of the substrate.decreasing the activation energy of the reaction.decreasing product stability.increasing the activ...

Natural proteins are composed primarily of $20$ $\alpha$-amino acids. Which one of the following statements is true for any of these amino acids in a solution of pH $1.5$...

Which one of the following organisms is an indicator of fecal contamination?$\textit{Escherichia coli}$$\textit{Streptococcus lactis}$$\textit{Bacillus subtilis}$$\textit...

The surface area (in $m^2$) of the largest sphere that can fit into a hollow cube with edges of length $1$ meter is ______Given data: $\pi=3.14$

In a thin layer chromatography experiment using a silica gel plate, a compound showed migration of $12.5$ cm and the solvent front showed migration of $18$ cm. The $R_f$ ...

$\underset{x \to 0}{\lim} \dfrac{\sin(x)}{x}$ is ________

Which one of the following mechanisms is used by human pathogens to evade host immune responses?Somatic hypermutationAntibody productionAntigenic variationComplement acti...

If the nucleotide composition $(\%)$ of a viral genome is $A = 10$, $U = 20$, $C = 40$, and $G = 30$, which one of the following is this genome?Double stranded RNASingle ...

Which one of the following techniques can be used to determine the structure of a $15$ kDa globular protein at atomic resolution?Raman spectroscopyIR spectroscopyUV spect...

Assertion [a]: Gram negative bacteria show staining with saffranin.Reason [r]: Gram negative bacteria have an outer membrane with lipopolysaccharides.Both [a] and [r] are...

The plant hormone indole-$3$-acetic acid is derived fromhistidinetyrosinetryptophanproline