Practice set 1 with solution 03.11.2020 (Part 2)

 Practice set 1 with solution 03.11.2020 (Part 2)

21) Sephadex has an exclusion limit of 80, 000 molecular weight for globular proteins. When this material was used to separate alcohol dehydrogenase (MW 150, 000) from b amylase (MW 200, 000) the result will be?

(a) Alcohol dehydrogenase elutes first    (b) β-amylase elutes first

(c) β-amylase will not elute                     (d) No separation.

 

Ans:(d) No separation occurs because in size exclusion chromatography small molecules can enter the poresin the beads where as larger molecules can not. So, larger molecules move faster and elute first. But in this case, exclusion limit of sephadex is 80,000 molecular weight and molecular weight of both alcohol dehydro-genase and α-amylase is higher than the exclusion limit. Thus, both are elute simultaneously without entering in the beads.

 

22) In which of the following combination the name of hormone, its chemical type & its tissue of origin correctly matched?

(a)Aldosterone, Peptide, Pancreas

(b)Glucagon, peptide, cortex Adrenal

(c)ACTH,peptide,adrenalcortex

(d)Vasopressin,Peptide,posterior pituitary.

 

Ans:(d) Vasopressin also known as anti-diuretic hormone is a peptide hormone which is secreted from posterior pituitary.

23)Which of the following plant hormones is incorrectly paired with its function?

(a) Auxins –– responsible for apical dominance

(b) Abscisic acid –– regulates the rate of transpiration

(c) Cytokinins –– delays senescence (aging and decay)

(d) Gibberellins –– promotes bud and seed dormancy

 

Ans: (d) Gibberellin causes seed germination by promoting the synthesis of variety of hydrolytic enzymes that are involved in the solubilization of endosperm reserves. It breaks dormany of seeds and buds.

 

24) An enzyme is discovered that catalyzes the chemical reaction.

                              A B

Researchers find that the K_cat is 400 S^–1 If [Et] = 300 nm and concentration of substrate A = 400 mm, the reaction velocity is 8.0 mm s–1 calculate the Km for substrate A?

(a) 10 mm    (b) 0.20 mm    (c) 20 mm   (d) 0.10 mm

 

Ans: (c)

 

25) PROSITE is a database used for?

(a) Nucleotide sequencing                     (b) Protein sequencing

(c) 2-D electrophoresis                          (d) Sequence Tagged site

Ans: (b) PROSITE is a database used for protein sequencing

 

26) Match the following

(P) Flippase (1) move any membrane phospholipids across the  bilayer    

                              down its concentration gradient

(Q)Floppase (2)transport glycerophospholipid from the outer   mono-

                               layer to the cytoplasmic surface of the  membrane.

(R)Scramblase  (3) move plasma membrane phospholipids from cytosolic to

                               the extracellular leaf

 (a) P 2, Q 3, R1    (b) P 1, Q 2, R 3  (c) P 3, Q 2, R1    (d) P 1, Q 3 ,R2

 

Ans:(a)Flippase-transport glycerophospholipid from outer monolayer to the cytoplasmic surface of the plasma membrane.Floppase-move plasma membrane phospholipids from cytosolic to extracellular leaflet.Scramblase -move any phospholipid across the bilayer down its concentration gradient.

 

27)Vincristin and Vinblastin, the chemical substances that can cure leukemia, are obtained from

(a) Rauwolfia serpentine              (b) Catharanthus roseus

(c) Withania somnifera                 (d) Strychnos nux-vomica

 

Ans: (b) Vincristin and Vinblastin, the chemical substances that can cure leukemia are obtained from Catharanthus roseus.

 

28) A coronary sulcus is found?

(a) Upon surface of liver between right and left liver lobes

(b) Upon heart surface between right and left auricles

(c) Upon heart surface between ventricle and atrium

(d) Upon heart surface between right and left ventricles.

Ans: (c)Coronary sulcus is found upon heart surface between vertricle and atrium. It is also known as atrioventricular sulcus.

 

 

29) Which of the following pairs are correctly matched?

P. 2, 4-dinitrophenol – Uncoupling agent in oxidative phosphorylation

Q. Oligomycin–Inhibitor of ATP formation in oxidative phosphorylation

R.Valinomycin– Ionophore carries potassium through the mitochondrial menbrane

S.Iodoacetate–Separates the phosphorylating F1-ATPase from the inner Mitochondrial membrane

Select the correct answer from the codes given below Codes:

(a) P, Q and S    (b) P, R and S      (c) Q, R and S     (d) P, Q and R

 

Ans: (d) correctly matched

(P)2,4-dinitrophenol–– uncoupling agent in oxidative phosphorylation.

(Q)Oligomycin---Inhibitor of ATP formation in oxidative phosphor-rylation. It completely blocks ATP synthesis by blocking the flow of protons through Fo of ATP synthase.

(R)Valinomycin--Ionophore carries potassium through the mitocho-ndrial membrane.

(S) Iodoacetate-- is not involved in separation of F1 - ATPase rather it is a potent inhibitor of glyceraldehyde – 3 phosphate dehydrogenase (glycolytic enzyme).

 

30) I place a cell in a solution. Over a period of time, I notice that the cell shrinks, as if it is losing water. Which of the following seems likely?

(a) The solution is a strong buffer

(b) The solution is an acid

(c) The solution has more dissolved solutes than the cell does

(d) The solution has fewer dissolved solutes than the cell does

 

Ans: (c)If the cell shrinks that means the solution has more dissolved solutes than the cell does. If a cell kept in a solution of higher concentration water diffuse out of the cell. This is called exosmosis.

 

31) Which of the following plants show resistance to heavy metal?

(a) Viola calaminaria              (b) Thlaspi alpestre

(c) Minuartia verna                 (d) All the above

 

Ans: (d) Viola calaminaria, Thlaspi alpestre and Minuartia verna-show resistance to heavy metal.

32) Mechanism by which Antidiuretic hormone increases water reabosorption in kidneys is?

(a) By directly acting on luminal membrane

(b) It acts on reticular structures in cytoplasm

(c) It activates enzyme guanyl cyclase

(d) It activates enzyme adenyl cyclase

Ans: (d)Antidiuretic hormone is a protein hormone which cannot diffuse through the lipid layer of plasma membrane. Receptor protein of this hormone is large transmembrane integral proteins of the plasma membrane of target cell. As the molecule of a receptor protein binds with the hormone, it gets stimulated. In turn it stimulates a molecule of enzyme adenyl cyclase.

 

33)Chemotropic movement of pollen tubes towards the micropylar end of the ovules in many cases has been attributed to the presence of?

(a) Mucilaginous substances on stigmatic papillae

(b) Auxins gradient through stylar tissue

(c) Gibberellin gradient through stigmatic and stylar tissue upto embryo sac

(4) Calcium gradient through stylar tissue upto embryo sac

 

Ans: (d)Chemotropic movement of pollen tubes toward the micropylar end of the ovules in many cases has calcium gradient through stylar tissue upto embryo sac. A growing pollen tube shows a tip-focused gradient of free Ca+2 ions. Conditions which inhibit pollen tube growth block influx of Ca+2 , reducing the intracellular Ca+2 gradient at the tip.

 

34) The “Master Regulatory Gene” is located on which chromosomes in humans?

(a) x chromosome                             (b) Y chromosome

(c) Both X, Y chromosome               (d) Autosomes

 

Ans: (b) The “master Regulatory gene “ is located on Y chromosome in humans, Sex determining region, Y (SRY) gene is the only gene on Y chromosome that is necessary to initiate testies development.

 

35)Which of the following statements gives a correct explanation for the use of vectors containing drug resistance genes in the cloning of recombinant DNA (cDNA) molecules?

(a) The products of the drug resistance genes protect the cDNA from destruction by the host cell

(b) The drug resistance genes provide additional base sequences that enable the vector to accommodate larger inserts of cDNA

(c) Entry of the vector containing the cDNA and the drug resistance genes into the host cell renders the later identifiable as it is now resistant to antibiotic drugs

(d) The cloned cDNA imparts drug resistance upon any cellular system with which it is used

Ans: (c)Entry of the vector containing the cDNA and the drug resistance genes into the host cell renders the later identifiable as it is now resistant to antibiotic drugs.

 

36) Gene for an enzyme which catalysis synthesis of a secondary metabolite in an angiosperm was transferred to a bacterial expression vector. But it was found that transgene was expressed but a functional enzyme was not synthesized which could be the best possible explanation?

(a) Plant enzyme was not stable in bacteria

(b) Post translational modification did not occur

(c) The promoter used were not appropriate

(d) Both B and C

 

Ans(b); Transegene was expressed but a functional enzyme was not synthesized which means post translational modification did not occur in the products encoded by transcend.

 

37) Amino acid residues present in silk fibroin, permitting a close packing of b sheets and an interlocking arrangement of R groups?

(a) Gly, Val      (b) Leu, Arg         (c) Ala, Gly        (d) Gly, His

 

Ans:(c)Silk fibrion is rich in Ala and Gly residues, permitting a close packing of b sheets and an interlocking arrangements of R groups.

38)Match the following:

Column I

Column II

(P) Metaxenia (Q)True  polyembryony (R) Xenia (S)False polyembryony

(I) When extra embryos are developing in one embryosac other than the one in which zygotic embryo is developed (II) More than one embryo are formed by splitting of normal zygote (III) Effect of pollen on character of the seed coat/ pericarp (VI)Effect of female gamete on character of seed  coat (V)Influence of male gamete on the development of endosperm. (VI)When embryos arise in the same embryosac in which zygotic embryo has developed.

 

(a) P- V, Q I, R IV, SVI              (b) P- IV, Q I, R III,S II

(c) P- III, Q VI, R V, S I             (d) P -V,Q I, R III,S IV

 

Ans:(c) Metaxenia ----effect of pollen on the character of the seed coat or pericarp.True polyembryony-----when embryo arises in the same embryosac in which zygotic embryo has developed. Xenia -----Influence of male gamete on the development of endosperm. False Polyembryony ---When extra embryos are developing in one embryosac other than the one in which zygotic embryo is developed.

 

39)Match the following products with the microbes which produce them on large scale and find the correct combination

           Product                       Microbe

     (P) Lysine —              Brevibacterium spp.

     (Q) Glutamic acid — Corynebacterium glutamicum

     (R) Gibbellic acid — Fusarium mohiliforme

     (S) Riboflavin —      Eremothecium ashbyi

(a) Q, R        (b) P, Q       (c) R, S            (d) R, S

 

Ans:(c)Correct combination

Glutamic acid –– Corynebacterium glutamicum.

Riboflavin –– Eremothecium ashbyi.

40) A radiolabelled CO₂ will release in which of the following case

(a) When acetyl Co-A entering Kreb cycle has radio labelled

(b) Glycine entering glycine decarboxylase system has radiolabelled a C

(c) Glycine entering glycine decorboxylase system has radiolabelled C at the –coo group

(d)When gamma-carbon of acetoacetate is radio-labelled during formation of ketone bodies

 

Ans:(c)A radiolabelled CO2 will release if glycine has radiolabelled C at the –COO¯ group enter into glycine decarboxylase system because during decarboxylation CO2 is released from carboxylic group of glycine