IIT JAM Biotechnology Mock Test 2 - Biotechnology Engineering (BT) MCQ

Ionic radii  (Ne = Number of electron present. Z = Atomic number)
More number of electrons than parent causes more electronic repulsion as a result of which ionic radii increases. The conect order of ionic radii is O^2- > F^- > Na⁺ > Mg²⁺ > Al³⁺

The ratio of the radii of the nuclei will be,

Now, we know that the radius R of a nucleus is related to its mass number A by

The radius of the n^th Bohr orbit for hydrogen atom is given by,
R_n = n²R₁ [R₁ is the radius of the first Bohr orbit] [ n = 1,2,3 .....]

For adiabatic process of an ideal gas, we have

Plasmalogen is a lipid with ether linkage between glycerol & fatty acid chain at C - 1 or C - 2 of glycerol.
In case of plasmalogens, the fatty acyl chain has unsaturation & is therefore called as alkenyl fatty acyl chain. Thus, when it forms ether linkage, as plasmalogens, such compounds are called alkenyl ether lipid.

Suicide inactivators are compounds that form covalent linkage with enzyme active site and permanently deactivate/ inhibit the enzyme.
Examples include azaserine and 5 - fluorouracil.

Mismatch repair system is an essential repair system in all organisms ranging from prokaryotes to eukaryotes. This system works by recognising the hemimethylated status of dsDNA.DNA in bacteria is methylated at adenines present in GATC sequences, but soon after replication parent strand is methylated, but daughter strand is not, thereby forming hemimethylated DNA. This hemimethylated DNA is recognised by mismatch repair proteins before initiating repair.

Complementary DNA (cDNA) is synthesized from mRNA by reverse transcriptase enzyme. Since mRNA possesses poly-A tail at its 3’end, so the complementary cDNA formed possesses poly T-stretch. While forming ds cDNA, the complementary strand consists of poly A stretch, thereby giving rise to homopolymeric sequence of A and T base pairs in ds cDNA.

Partial/parietal cleavage is another name for meroblastic cleavage. A fertilized egg cell containing large amount of yolk undergoes meroblastic/partial cleavage, because the presence of more yolk makes it difficult to cleave a cell. 

Using Wien's displacement law, we have
λT = Constant

Since the conversion of ice into water is a spontaneous process, we have ΔS _universe  > 0

Wax is the chief storage form of metabolic fuels is planktons.

T_m for desaturation of different duplexes is RNA-RNA > DNA-RNA > dsDNA. Exact reason for such order is however poorly established. So, correct order will be x > z > y.

The Linking number (Lk) is the number of times the axis of a DNA molecule crosses itself around the central axis. Lk determines the degree of supercoiling. The linking number of DNA molecule cannot change until the two strands are covalently intact. It can only be changed by breaking and rejoining of strands.

Replication is prokaryotes is technically similar to that of eukaryotes  except a few differences like prokaryotes have one origin of replication while eukaryotes have many. Actually eukaryotes have quite longer genomes than prokaryotes and thus they have more origins of replication. Also, because of smaller genomes prokaryotes have faster rate of replication

The initiation stage of protein synthesis involves the formation of initiation complex. In E.coli, this complex involves small ribosomal subunit (30S), mRNA template, three initiation factors and a special initiator tRNA carrying N-formyl methionine (Met-tRNA^fmet)

Catabolite activator protein (CAP) acts as a glucose sensor. It activates transcription of the operon, but only when glucose levels are low. CAP senses glucose indirectly, through the “hunger signal” molecule cAMP, whereby a CAP-cAMP complex is recruited to the promoter site. Therefore, they exert a positive regulatory effect on lac operon.

During pattern formation, it is crucial for cells of the developing embryo to communicate with one another so that each cell will “know” its relative position within the emerging body plan. The intercellular molecular signals that ultimately drive the process of pattern formation provide positional information. These signals may be chemicals released by certain embryonic cells that diffuse through the embryo and bind to other cells. These diffusible signals are called morphogens. Often at times, it is the concentration of the morphogen the target cell senses that provides information about the target cell’s proximity to the releasing cell.

During epiboly, a sheet of cells spreads by thinning, i.e., the sheet thins, while its overall surface area increases in the other two directions. Epiboly can involve a monolayer (i.e., a sheet of cells one cell layer thick), in which case the individual cells must undergo a change in shape. In many kinds of embryos, gastrulation also includes spreading of epithelial sheets. e.g., the edges of the bird epiblast crawl outward over the inside surface of their vitelline membrane. In other cases, like involution, ingestion etc., however, a sheet that has several cell layer can undergo thinning by changes in position of its cells. 

The energy of n^th state of a hydrogen like atom [ having Ze charge at nucleus andd one electon (n) ] is

If a nuclei ^A_ZX undergoes α' or ‘ β ' decay, the following are the form of reactions:

For 'n' number of α decays the mass number of the parent nuclei should be reduced by 4n and as β -decay doesn't cause the mass number of the parent nuclei to change, we can conclude
4n = 238 - 206 = 32
n = 8
Now. as for the change in the atomic number we can conclude.
92 - 82 = n x 2 + m x (-1)
Since the atomic number decreases by 2 and increases by 1, for 'α' and a β -decays, respectively.
Putting the value of n, we find,