Experiments in Biochemistry（生物化学实验）期末考试答案 学堂在线

Experiments in Biochemistry（生物化学实验） - 南京大学 - 学堂在线

1.判断题 (1分)

Make sure the accuracy of the temperature and reaction time of the enzymatic reaction to ensure the identical conditions of each reaction system. ()

正确答案：正确

2.判断题 (1分)

Trypsin is a serine proteolytic enzyme extracted from the pancreas of cattles, sheeps and pigs. It can digest the peptide bond formed by the carboxyl groups of arginine and lysine residues in the polypeptide chain. ()

正确答案：正确

3.多选题 (2分)

If the reaction speed in each conical flask is very small, how to solve this problem? ()

AIncrease the extraction quantity and concentration of the enzyme

BChoose other biomaterials with high catalase activity

CChoose appropriate extraction conditions to avoid denaturation or deactivation of the enzyme

DIncrease the concentration of H₂O₂

正确答案：A,B,C (少选不得分)

4.填空题 (1分)

Besides Km, which enzyme parameter could also be obtained in this experiment?

正确答案：

填空1 : Vmax

5.多选题 (2分)

Which of the following factors are related to Km? ()

AEnzyme species

BSubstrate species

CSubstrate concentration

DEnzyme concentration

正确答案：A,B (少选不得分)

6.单选题 (1分)

In the present experiment, after calculating the substrate concentration ([S]) and the reaction rate (v), how to use the double reciprocal to plot? ()

A1/v on the abscissa, 1/[S] on the ordinate

Bv on the ordinate, [S] on the abscissa

C1/v on the ordinate, 1/[S] on the abscissa

Dv on the ordinate, 1/[S] on the abscissa

正确答案：C

7.单选题 (1分)

What is the unit of Km? ()

A mol

B L

C mol/min

Dmol/L

正确答案：D

8.判断题 (1分)

SDS is an anionic surfactant, which helps bacteria lyse and keep the protein maintaining a natural activity. ()

正确答案：错误

9.填空题 (1分)

 is the independent genetic factor out of chromosome in bacterial. It could self-replicate autonomously and stably inherit certain traits of bacteria.

正确答案：

填空1 : Plasmid

10.判断题 (1分)

In the final step of plasmid extraction, add the eluent to the center of the adsorption column, and leave it at room temperature for 2 minutes to fully dissolve the plasmid DNA which has been adsorbed by the column. ()

正确答案：正确

11.单选题 (1分)

The role of DuRed dye in agarose gel electrophoresis is ().

AParticipate in the formation of pore structure

BPre-stain the gel. Therefore, the plasmid DNA could emit fluorescence at 300nm, which is easily observed

CDenature plasmid DNA

DIndicate the position of forefront band in electrophoresis

正确答案：B

12.多选题 (2分)

According to the hydrolytic characteristics, catalytic conditions and modification capacity, restriction enzymes could be divided into ().

AType I

BType II

CType III

DType IV

正确答案：A,B,C (少选不得分)

13.单选题 (1分)

Which of the following operation of yeast RNA extraction is incorrect? ()

AExtraction with NaOH solution must be performed at 4 °C to ensure the biological activity of RNA.

B After centrifugation, carefully aspirate the supernatant with a dropper, and do not suck the lower cell debris. If the supernatant is still turbid, centrifuge again.

C When washing crude RNA, be careful not to splash water. Otherwise, the product will be very sticky and difficult to be collected.

D Orcinol solution is prepared with concentrated hydrochloric acid. The related operations must be performed in a fume hood.

正确答案：A

14.判断题 (1分)

In cells, DNA or RNA are usually protein-binding. ()

正确答案：正确

15.多选题 (2分)

During DNA extraction, chloroform-isoamyl alcohol and SDS are added. After centrifugation, the layers are shows in the figure. Which of the following statements are correct ?()

图片.png

AThe upper layer is an aqueous phase containing DNA, the middle layer is denatured proteins, and the lower layer is chloroform.

BThe upper layer is chloroform, the middle layer is denatured protein, and the lower layer is an aqueous phase containing DNA

CSDS can destroy the advance structure of proteins and cause the proteins to dissociate from DNA.

DChloroform is a proteins denaturant, which can precipitate protein and accelerate the separation of organic phase and aqueous phase.

正确答案：A,C,D (少选不得分)

16.填空题 (1分)

To quantify DNA with the diphenylamine colorimetric method, the absorbance value should be measured atnm.

正确答案：

填空1 : 595

17.单选题 (1分)

Diphenylamine colorimetric method could be used to identify ().

ADNA

BRNA

Call nucleic acids

Dbases

正确答案：A

18.判断题 (1分)

In SDS-PAGE, the migration rate of proteins only depends on the molecule size and has nothing to do with the charge and molecule shape. ()

正确答案：正确

19.多选题 (2分)

The role of SDS in this experiment is ().

APrecipitate protein

BBind with protein molecules in a certain proportion

CLet the proteins carry large amount of negative charges to eliminate the original charge difference

DFully depolymerize proteins into monomers

正确答案：B,C (少选不得分)

20.单选题 (1分)

In general, the concentration of stacking gel in discontinuous SDS-PAGE is ().

A5%

B8%

C12%

D10%

正确答案：A

21.单选题 (1分)

The pH of SDS-PAGE electrophoresis buffer is ().

A8.3

B 8.8

C 6.8

D 7.0

正确答案：A

22.填空题 (1分)

The sample should be loaded on the cellulose acetate membranethe shiny side (filled with "with" or "without").

正确答案：

填空1 : without

23.多选题 (2分)

Which of the following operations are correct in serum proteins separation by cellulose acetate membrane electrophoresis? ()

ABefore loading, sponge up the excess electrophoresis buffer on the surface of the film with filter paper.

BSome serum sample is dipped with the cross-section of a spotting slide and generally keep the slide-film contacting for 2 to 3 seconds during loading, until the serum penetrates the membrane.

CThe width of the loading is shorter than that of the membrane, avoid loading repeatedly.

DToo much loading will result in unclear band boundaries.

正确答案：A,B,C,D (少选不得分)

24.单选题 (1分)

The isoelectric point of immunoglobulin in serum is mostly around pH7. For example, pI of IgM is 7.0 and pI of IgA is 7.4. After cellulose acetate membrane electrophoresis using pH8.6 barbiturate sodium electrode buffer, which region will these two proteins locate at? ()

Anear Albumin

Bnear α1-globulin

Cnear α2-globulin

Dnear β-globulin

Enear γ-globulin

正确答案：E

25.判断题 (1分)

Proteins separated by cellulose acetate membrane electrophoresis are quantified according to the width of each band after electrophoresis. ()

正确答案：错误

26.判断题 (1分)

Cellulose acetate membrane electrophoresis has lower resolution than polyacrylamide gel electrophoresis (PAGE) in proteins separation. ()

正确答案：正确

27.判断题 (1分)

By pretreatment of fresh resin, the impurities, such as residual solvents, oligomers and a few heavy metal ions (such as Fe3+, Cu2+), could be removed ()

正确答案：正确

28.多选题 (2分)

Besides ion exchange column chromatography, other chromatography techniques include ().

AHydrophobic chromatography: Substances have different affinities to the hydrophobic groups coupled with the resin.

BAffinity chromatography: Substances bind to the specific groups of the resin with different affinities.

CGel filtration chromatography: It is based on the molecular weight difference of separated components.

DIsoelectric Focusing: The difference in isoelectric point among the separated substances. It is based on the isoelectric point difference of separated components.

正确答案：A,B,C,D (少选不得分)

29.填空题 (1分)

The resin should be added into the column(fill in “slowly” or “quickly”) to avoid producing air bubbles.

正确答案：

填空1 : slowly

30.填空题 (1分)

According to the different numbers of amino and carboxyl groups contained in amino acids, amino acids are divided into three categories: acidic amino acids,amino acids and basic amino acids.

正确答案：

填空1 : neutral

31.单选题 (1分)

When using Coomassie Brilliant Blue method to measure proteins, which of the following factors will interfere with the results? ()

APotassium ions

BMagnesium ions

CEthanol

DTritonX-100

正确答案：D

32.判断题 (1分)

When using ultraviolet absorption method to determine protein samples, quartz cuvette should be used instead of glass cuvette. ()

正确答案：正确

33.多选题 (2分)

What factors should be considered in the methods selection of protein concentration determination? ()

AThe properties of the analyzed protein

BThe sensitivity and accuracy required in the experiment

CInterfering substances present in the solution

DThe time it takes to determine the protein concentration

正确答案：A,B,C,D (少选不得分)

34.多选题 (2分)

Which of following amino acids have conjugated double bonds? ()

ATyrosine

BTryptophan

CAlanine

DPhenylalanine

正确答案：A,B,D (少选不得分)

35.判断题 (1分)

In order to obtain an accurate pH, it is best to use a pH meter for measurement. ()

正确答案：正确

36.填空题 (1分)

When the pH of the solution is equal to the isoelectric point of the protein, the solubility of the protein is the(fill in "highest" or "lowest")

正确答案：

填空1 : lowest

37.单选题 (1分)

The isoelectric point of casein is ().

A3.0

B4.7

C7.0

D7.6

正确答案：B

38.判断题 (1分)

When KOH is replaced with NaOH at the same concentration as the titration alkaline, only the molecular weight of KOH needs to be replaced with the molecular weight of NaOH in calculating the acid value. ()

正确答案：错误

39.判断题 (1分)

In order to deduct the background, the alcohol-ether mixture is used to dissolve the lipids needs to be titrated in advance. ()

正确答案：正确

40.填空题 (1分)

In constructing the standard curve of reducing carbohydrate, DNS reagentbe added to the blank tube (fill in "should" or " should not")

正确答案：

填空1 : should

41.多选题 (2分)

Anthrone colorimetric assay could be used to determine which of the following substances? ()

Amonosaccharide

Bstarch

Cfructose

Dglycogen

正确答案：A,B,C,D (少选不得分)

42.单选题 (1分)

Which following substances cannot be used as lipid extraction solvents ().

Aether

Bpetroleum ether

Cethyl acetate

Dwater

正确答案：D

43.填空题 (1分)

The heating instrument used for the extraction of crude lipids is.

正确答案：

填空1 : thermostat water bath

44.填空题 (1分)

Before extraction, the filter paper bag containing the sample should be placed in the.

正确答案：

填空1 : Extraction chamber

45.多选题 (2分)

Which of the following statements about this experiment are correct? ( )

AReducing carbohydrate is reductive and contain free aldehyde groups or ketone groups.

BTotal carbohydrate includes reducing carbohydrate and non-reducing carbohydrate.

CWhen determining the total carbohydrate in this experiment, it is necessary to firstly hydrolyze the total carbohydrate to reducing carbohydrate under acidic conditions.

D It is necessary to construct a standard curve using several concentrations of starch solution.

正确答案：A,B,C (少选不得分)

46.判断题 (1分)

After adding DNS reagent to the sample, the time of the boiling water bath does not need to be strictly controlled. ( )

正确答案：错误

47.单选题 (1分)

Which wavelength (nm) is used in the colorimetric assay? ()

A380

B450

C620

D560

正确答案：C

48.判断题 (1分)

Before adding the anthrone reagent, the test tube should be cooled in an ice water bath. ( )

正确答案：正确

49.判断题 (1分)

When the carbohydrate sample contains proteins, it can be directly measured without removing the proteins in advance. ( )

正确答案：错误

50.多选题 (2分)

What are the roles of 25% sulfuric acid in the experiment? ()

ADenature enzyme to stop the enzymatic reaction.

BProvide the acidic environment required for KMnO₄ titration.

C Speed up the enzymatic reaction.

D Improve the activity of catalase.

正确答案：A,B (少选不得分)