Biological molecules — MDCAT Biology MCQs

1

UHS MDCAT 2008

The optimum temperature for enzymes of human body is:

2

UHS MDCAT 2008

The two strands in DNA are coiled _ to each other.

3

UHS MDCAT 2008

Which of the following gives blue color with iodine?

4

UHS MDCAT 2008

Name the one involved in DNA replication.

5

UHS MDCAT 2008

The attraction among water molecules which hold water together is called:

6

UHS MDCAT 2008 FMDC MDCAT 2022

Which bond is the potential source of chemical energy for cellular activities?

7

UHS MDCAT 2008

In what direction can a DNA polymerase work when catalyzing the addition of nucleotide monomers?

8

UHS MDCAT 2009

Which of the following components is less resistant to decay?

9

UHS MDCAT 2009

Enzyme, after catalysis, detaches itself from the product:

10

UHS MDCAT 2009

Pepsin enzyme is produced in an inactive form and is activated in situation when it is required because:

11

UHS MDCAT 2009

The immediate source of energy for cellular metabolism is

12

UHS MDCAT 2018

Which lipid is hydrophilic and soluble?

13

UHS MDCAT 2019

Most proteins are made up of:

14

UHS MDCAT 2019

Starch is present in tubers, fruits, and grains but absent in animal cells. Instead, animals have a substance stored in liver and muscles known as:

15

UHS MDCAT 2019

Lipids contain double amount of energy as compared to the same amount of carbohydrates due to the presence of:

16

UHS MDCAT 2019

Ester linkages occur in:

17

UHS MDCAT 2022

DNA stores biological information in discrete units termed as:

18

UHS MDCAT 2022

Proteins are the main _ of the cell?

19

UHS MDCAT 2022

Which of the following is a conjugated molecule?

20

UHS MDCAT 2022

Butyric acid is a _ carbon fatty acid.

21

UHS MDCAT 2022

The unique three-dimensional shape of the fully folded polypeptide constitutes:

22

UHS MDCAT 2022

Upon initial hydrolysis, starch yields:

23

UHS MDCAT 2022

What is the color of the Chlorophyll-b molecule?

24

UHS MDCAT 2023

Most of the monosaccharides form a ring structure when in solution. For example ribose will form a five cornered ring known as

25

UHS MDCAT 2023

Which statement is true about regarding both starch and cellulose?

26

UHS MDCAT 2023

The specific heat of vaporization of water plays an important role in the regulation of heat produced by

27

UHS MDCAT 2024

Which option is correct about a chlorophyll a molecule?

28

UHS MDCAT 2024

The nucleus takes dyes due to the presence of:

29

UHS MDCAT 2024

Which monosaccharide will from a gluco-pyranose ring in solution?

30

UHS MDCAT 2024

The hydrophilic end of the phospholipid molecule is polar because of the presence of:

31

UHS MDCAT 2024

Polysaccharides in plants are synthesized by the process of:

32

UHS MDCAT 2024

When glycerol reacts with fatty acid, which type of chemical bond will form?

33

UHS MDCAT 2024

Mono-saccharides have a general formula represented by:

34

PMDC MDCAT 2025

Glycoproteins are formed as a result of the combination of:

35

PMDC MDCAT 2025

The main role of mRNA during protein synthesis is to:

36

PMDC MDCAT 2025

Peptide bonds are Important in protein because they:

37

PMDC MDCAT 2025

Which one of the following biomolecules is a polymer/polysaccharide?

38

PMDC MDCAT 2025

_ arranges the DNA into the chromosomes in a eukaryotic cell

39

PMDC MDCAT 2025

Enzymes belong to which class of biomolecules?

40

PMDC MDCAT 2025

Identify the most appropriate function of chromosomes

41

PMDC MDCAT 2025

Which of the following types of RNA makeup the largest proportion of total cellular RNA?

42

PMDC MDCAT 2025

Which of the following is a key feature of RNA?

43

PMDC MDCAT 2025

The following is an example of a globular protein

44

PMDC MDCAT 2025

The secondary structure of proteins is stabilized by:

45

PMDC MDCAT 2025

Which of the following is the correct higher (left) to lower (right) sequence of molecules involved in the flow of genetic information in the cell?

46

PMDC MDCAT 2025

An oligosaccharide is made up of at least:

47

PMDC MDCAT 2025

Which property of water helps in moderating Earth's climate and maintaining stable temperature in aquatic environment?

48

PMDC MDCAT 2025

A mature duplicated chromosome consists of:

49

PMDC MDCAT 2025

The complementary base pairing in DNA is important because it:

50

An activated enzyme consisting of a polypeptide chain and a co-factor is called a/an:

51

Penicillin is a kind of antibiotic that works as

52

Which statement about enzymes is essential to the lock & key hypothesis?

53

An enzyme and its substrate react with each other through a _ of enzyme.

54

Balochistan MDCAT 2024

Which one of the following is not an enzyme?

55

The detachable _ is called as an activator, if it is an inorganic ion

56

Balochistan MDCAT 2024

Which of the following is / are the characteristics of the enzymes?

57

KPK MDCAT 2024

Optimum pH for pancreatic lipase is:

58

KPK MDCAT 2024

How do enzymes enable the conversion of substrates into products by?

59

KPK MDCAT 2024

Which enzyme is secreted in the active form?

60

When inhibitor compete with substrate for active site, it is:

61

KPK MDCAT 2024

Enzymatic activity can be inhibited by?

62

KPK MDCAT 2024

Catalase can be activated at pH:

63

KPK MDCAT 2024

What happens to the enzyme after an enzyme-catalyzed reaction?

64

Cyanides occupy the enzymes by forming covalent bond, thus comes under the------- inhibitors.

65

FMDC MDCAT 2024

Lock and key model (1890), was modified by

66

FMDC MDCAT 2024

A covalently bonded inorganic ion with protein part of an enzyme is termed as _

67

UHS MDCAT 2024

Induced fit model of enzyme activity suggests that enzyme:

68

Sindh MDCAT 2024

The active site of the enzyme is the region that:

69

Sindh MDCAT 2024

Molecules that bind to an enzyme away from the active site and increase the function of that active site are known as:

70

Sindh MDCAT 2024

The term enzyme was coined by:

71

Sindh MDCAT 2024

The human enzymes are highly active at about:

72

Sindh MDCAT 2024

Koshland proposed a model for enzymes with the name of "induced fit model" in the year:

73

Balochistan MDCAT 2022

The catalytic site of enzyme is made up of how many amino acids?

74

Balochistan MDCAT 2022

Optimum pH for digestive enzymes of stomach is?

75

Balochistan MDCAT 2022

The temperature at which inactive enzyme regains it's function is called as?

76

_ reduces the enzyme productivity by blocking the substrate to enter the active site due to similar shape.

77

In terms of enzyme action, maximum temperature refers to a temperature at which _.

78

The maximum enzymatic activity of pepsin is shown at _.

79

The catalytic activity of enzyme is restricted to a small portion called _.

80

KPK MDCAT 2022

Most of the coenzymes are the derivatives of:

81

UHS MDCAT 2022

What is the best physiological pH for optimum functioning for most of the cellular enzymes of human?

82

UHS MDCAT 2022

Zinc ion is attached at the active site of the enzyme carboxypeptidase. The zinc ion functions as:

83

UHS MDCAT 2022

Non-competitive inhibitor molecules have:

84

UHS MDCAT 2022

Competitive inhibitors compete with?

85

Sindh MDCAT 2022

Each enzyme has a dimple or groove at a specific side called:

86

Sindh MDCAT 2022

When substrate combines the active site of an enzyme, it induces a conformational changes that enable the enzyme to perform:

87

Sindh MDCAT 2022

When substrate combines the active site of an enzyme it induces a conformational changes that enable enzyme to perform:

88

Sindh MDCAT 2022

Enzymes are generally inactivated rapidly by exposure to UV high and also a, ẞ rays because it alters the:

89

Sindh MDCAT 2022

They are inhibitors of key enzymes in the nervous system:

90

Sindh MDCAT 2022

A co-enzyme constitute about a certain % of the portion of the entire enzyme:

91

Balochistan MDCAT 2023

Cyanides block the action of enzymes by combining with:

92

Balochistan MDCAT 2023

Both enzymes and coenzymes are:

93

UHS MDCAT 2022 Balochistan MDCAT 2023

Enzymes lower the activation energy by stabilizing the transition state of a metabolic reaction due to?

94

Balochistan MDCAT 2023

The temperature at which an inactive enzyme regains its function is called:

95

Adding substrates will NOT make a difference to the enzyme catalysed reaction:

96

What is 'Flavin adenine dinucleotide'?

97

Which of the following is an example of hydrolase:

98

Enzymes are...

99

What alters the shape of enzymes and makes them functional.

100

Sindh MDCAT 2023 (Retake)

Lock & key model of enzyme action proposed by Emil Fischer suggested that.

101

Pepsin works best at a pH of----

102

Trypsinogen can be activated by the action of:

103

The inhibition, in which the inhibitor does not combine directly with the enzyme but binds to the enzyme-substrate complex is called:

104

The optimal pH of lipase (pancreas) is:

105

An example of competitive inhibitor molecule is:

106

Enzymes present in mammals work best at about:

107

All of the following are related to enzymes except:

108

Which one of the following factors does not affect the rate of enzyme action?

109

UHS MDCAT 2023

Competitive inhibitors stop an enzyme from working by:

110

UHS MDCAT 2023

The function of hyaluronidase enzyme is:

111

NAD is important?

112

UHS MDCAT 2023

The active sites of enzymes are composed of?

113

Competitive inhibitors are _?

114

UHS MDCAT 2023

Which enzyme is different from others?

115

UHS MDCAT 2023

The enzyme which can work on ph 7 of the medium is?

116

FMDC MDCAT 2023

Select a regulatory enzyme:

117

FMDC MDCAT 2023

Which Proteolytic enzyme is NOT secreted in inactive form?

118

FMDC MDCAT 2023

Non protein but inorganic detachable co-factor is called:

119

Enzymes work by lowering the _ of the reactions they catalyze.

120

The Lock and Key Model for enzyme action proposed by Emil Fischer suggests that:

121

Sindh MDCAT 2023

A chemical substance that can react with an enzyme faster than a real substrate and without producing a product is

122

Sindh MDCAT 2023

The structure of an enzyme is altered by:

123

Sindh MDCAT 2023

Penicillin blocks the active sites of an enzyme that many bacteria use in making cell walls. It is an example of:

124

Sindh MDCAT 2023

At equilibrium, a scientist added more substrate and observed an increase in the rate of the reaction, which soon declined. He added some more substrate, but this time the rate of the reaction remained unaffected. What was the reason?

125

Holoenzyme is?

126

Which factor is responsible for the inhibition of the enzymatic process during feedback?

127

What is common in both competitive and non-competitive inhibition?

128

Enzymes that require an optimum temperature lower than 37°C for their proper function are present in:

129

An enzyme that is not protein in nature:

130

An enzyme requires Mg+2 to catalyze the substrate. The Mg+2 is identified as:

131

The atoms, groups of atoms and molecules that join with enzymes altering their shape and making them functional:

132

UHS MDCAT 2024

What is true about enzymes?

133

The reactants on which enzyme work are:

134

Enzymes catalyze all of the following except:

135

If enzymes stop their functions, then biochemical reactions would:

136

The transition state structure of the substrate formed during an enzymatic reaction is:

137

Change in temperature from 30˚C to 40˚C in human body will cause:

138

Optimum pH of enterokinase is:

139

ES complex is converted into a product by:

140

Which type of energy does heat provide to activate a chemical reaction?

141

If more substrate is added to an already occurring enzymatic reaction, and more enzyme activity is seen, then this is because of which of the following?

142

If the non-protien part is loosely attached to the protein part in the enzyme, it is known as _.

143

Most of the enzyme reactions are_?

144

NUMS MDCAT 2019

Amygdalin is a naturally occurring compound that is commonly found in seeds of apricot and apple. If you eat at least 200 of these seeds, it can be deadly. What is this harmful by product when amygdalin is reduced by enzymes in our body?

145

Conversion of glucose 6-phosphate into fructose 6-phosphate is done by:

146

This figure represents_inhibitor.

147

Bond sensitive to change in temperature and pH are respectively:

148

UHS MDCAT 2016

Which one of the following graphs shows how the rate of reaction of pepsin is affected by pH?

149

If the concentration of the substrate molecule is higher than the enzyme, then the rate of reaction would be:

150

_ suggested that each enzyme had a particular shape into which the substrate fit exactly.

151

The lower the activation energy, the _ the reaction will be.

152

FMDC MDCAT 2018

Three of the following statements about enzymes are correct and one is wrong. Which one is wrong?

153

UHS MDCAT 2014

A cofactor tightly bound to the enzyme on the permanent basis is called:

154

"Zymase"- a group of 14 enzymes used in the fermentation of starch, is present in:

155

Allosteric enzymes have _ major site(s).

156

Prosthetic groups are:

157

Coenzymes are closely related to:

158

Enzymes function most effectively over a narrow range of pH known as:

159

If the product of a pathway down-regulates its own synthesis, this phenomenon would be called:

160

The role of an enzyme in reactions is to:

161

UHS MDCAT 2015

Which one of the following is an example of a competitive inhibitor?

162

Restriction endonucleases:

163

If another molecule, having a shape very similar to the enzymes substrate, binds to its active site, it would then _ the enzyme's function.

164

NUMS MDCAT 2020

When an inhibitor binds to an enzyme other than the active site and alters its structure, then it is called:

165

NUMS MDCAT 2020

Non-protein and organic, detachable co-factors are called:

166

FMDC MDCAT 2022 PMDC MDCAT 2020

Most enzymes have an optimum temperature of around:

167

Balochistan MDCAT 2010

Some enzymes require the presence of a non protein molecule to behave catalytically. An enzyme devoid of this molecule is called a(n):

168

Competitive inhibitors and real substrate often have similar:

169

Sindh MCAT NTS 2009 LUMHS

The function of an enzyme is to:

170

The part of an enzyme where a substrate binds is called the:

171

What does the active site of the enzyme do?

172

Which of the following is the optimum temperature for all enzymes to work in body?

173

A non-protein chemical compound which is required for enzyme's catalytic activity is?

174

An enzyme can:

175

Which of the following reacts with an enzyme at site other than the active site?

176

ETEA MDCAT 2019

The optimum pH of enzyme urease is

177

The main difference between catalysts and enzymes is:

178

UHS MDCAT 2017 (Reconduct)

Name the inhibitors which can be neutralized by adding more substrate:

179

UHS MDCAT 2017 (Reconduct)

Lock and Key model was explained by:

180

UHS MDCAT 2017 (Reconduct)

Enzymes have what effect on the end-product?

181

Coenzymes are derived from:

182

UHS MDCAT 2013

The view that active site of an enzyme is flexible and when a substrate combines with it, cause changes in enzyme structure is known as:

183

UHS MDCAT 2013

Optimum pH value for the working of pancreatic lipase is:

184

UHS MDCAT 2011

_ forms weak linkages with enzymes and their effect can be neutralized completely or partly by an increase in the concentration of the substrate.

185

The inhibitors that bind tightly and permanently to enzymes and change their globular structure and catalytic activity are:

186

The type of inhibition in which the inhibitor has no structural similarity to the substrate and combines with the enzyme at other than the active site is called:

187

UHS MDCAT 2015

The specific substances (metabolite) that fits on the enzyme surface and is converted to products is called

188

UHS MDCAT 2015

Which molecular structure of enzyme is essential for activity of enzyme?

189

_ are biologically active proteins.

190

Enzymes do not change which of the following?

191

Which of the following best describes the prosthetic group?

192

If the pH of a solution changes slightly, there is a _.

193

While bound to the active site, the substrate is converted into which of the following?

194

The rate of reaction is directly proportional to the concentration of an enzyme. Which statement is incorrect in this respect?

195

Which of the following is true in case of induced fit model?

196

Enzymes for light-dependent reactions of photosynthesis would most likely be associated with _.

197

The substrate concentration that produces exactly half of the maximum reaction rate can be described by?

198

Enzymes are globular proteins because ----------

199

'Transmetylases' help in transfer of which of the following?

200

Which of the following is a water soluble vitamin?

201

The number of models that represent enzyme-substrate model is ----

202

What would you predict would happen to pancreatic enzymes if they were introduced to the stomach?

203

Enzyme-catalyzed modifications are?

204

Vitamins which are not stored in body are called?

205

Enzymes that are involved in the control and regulation of biological processes are?

206

What type of bonds exist between an enzyme and its prosthetic group?

207

The optimal temperature for enzymes to work in body is how many degree celsius?

208

Which of the following vitamin acts as a coenzyme?

209

Nicotinamide adenine di nucleotide is an example of:

210

The complex that forms when a substrate binds to enzyme is called?

211

Which statement correctly describes why enzyme activity increases with increased enzyme concentration?

212

Biological molecules which catalyze a biochemical reaction and remain unchanged after completion of reaction are called?

213

The primary function of cofactors is to _.

214

Which step causes activation of the catalytic site of an enzyme?

215

The following enzymes are regulated by calcium ions _

216

Which type of bond is formed in maintaining the tertiary structure of proteins?

217

A cofactor made of an inorganic ion which is detachable is called a _.

218

Enzyme-substrate specificity is a result of which property of enzymes?

219

In mixed inhibition, the allosteric effect affects the _.

220

Which of the following is NOT a class of enzyme?

221

A detachable organic cofactor is known as

222

A vitamin that doesn't act as a coenzyme is:

223

What affect do enzymes have on the activation energy of a reaction?

224

Substrate for succinic dehydrogenase is:

225

Pancreatic zymogens are only activated when they reach at?

226

What is not true about enzyme?

227

The rate of reaction of enzyme directly depends upon which of the following?

228

In non-competitive inhibition, the extent of inhibition depends only on?

229

An enzyme without its cofactor is called a/the _.

230

Which of the following is FALSE concerning enzymes?

231

The optimum pH of "salivary amylase" is:

232

In which of the following categories do reversible inhibitors usually constitute?

233

The active site on an enzyme:

234

The active form of an enzyme is called:

235

Bond specificity of an enzyme is also known as?

236

Which of the following strategies of enzymatic inhibition is used by noncompetitive inhibitors?

237

If the concentration of enzyme is kept constant and the amount of substrate is increased to a point where further increase in the substrate concentration does not affect the reaction rate, this phenomenon is due to?

238

Inhibitors which block the enzyme by forming weak bond are called?

239

If the enzyme changes the active site, the rate of reaction will undergo which of the following changes?

240

What are the main distinguishing features of globular proteins?

241

In mixed inhibition, the inhibitor binds on the enzyme?

242

Which of the following would most greatly increase the activity of an enzyme functioning in the small intestine?

243

Enzymes are produced in inactive form by the cell and enclosed in which of the following?

244

Enzymes which control cellular respiration are present in?

245

Malonic acid is an example of which type of inhibitors?

246

Which one of the following statements about enzymes is not true?

247

A metal cofactor which is used in the process of glycolysis is?

248

Which term is used to refer to an inactive enzyme precursor?

249

The rate of an enzyme catalyzed reaction:

250

Ligase helps in which of the following reactions?

251

Allosteric enzymes consist of multiple?

252

Irreversible modifications require the synthesis of which of the following:

253

An inhibitor is added, disrupting the function of a particular enzyme. The experimenter adds more substrate, and enzyme function increases again. These results indicate the involvement of what type of inhibitor?

254

Extreme change in pH results in which of the following?

255

Enzymes showing substrate specificity are specific to, how many substrates?

256

Which of the following changes could lead to loss of enzymatic function?

257

A chemical substance which can react (in place of substrate) with the enzyme but is not transformed into product(s) and thus blocks the active site temporarily or permanently is called:

258

A chemical substance that can react with an enzyme but not transform into a product is called a/an:

259

All of these are inhibitors of enzymes except:

260

Which of these enzymes works best at a pH of 2.00?

261

Lock and key model was proposed by _?

262

The specificity of an enzyme is due which of the following?

263

Enzymes which are involved in transfer of electrons are known as?

264

The enzyme-substrate complex is formed in which part of the enzyme molecule?

265

Decreasing Vmax in uncompetitive inhibition also decreases?

266

Which of these enzymes works best at a pH of 9.70?

267

Non-toxic vitamins include which of the following?

268

Covalent modification means change in?

269

A three-dimensional cavity bearing a specific charge by which the enzyme reacts with its substrate is called a/an:

270

Which one forms the raw material for coenzymes?

271

If the non-protein part of the Enzyme is covalently bonded to the enzyme, it is known as?

272

A researcher has designed a new type of inhibitor that binds at the active site of an enzyme. What type of Inhibition does this molecule display?

273

Feedback inhibition in most metabolic pathways involves which type of enzymes?

274

In competitive inhibition, the two things that binds to enzyme active site are?

275

The optimal pH in which the enzyme enterokinase functions is?

276

Catalysts that increase the rate of biological chemical reaction are:

277

Enzymes that are, an integral part of ribosomes, are involved in the synthesis of which of the following molecules?

278

In competitive inhibition, the inhibitor has similar _ to the substrate.

279

On which part of the enzyme is the enzyme-substrate complex formed?

280

Most co-enzymes are derived from:

281

Which of the following is an irreversible inhibitor?

282

Enzymes are biological catalysts that speed up a reaction by _ the activation energy.

283

Enzymes are biological catalysts that _ a reaction.

284

Which of the following is not a coenzyme?

285

The enzyme does not affect:

286

The end product of an enzymatic reaction inhibits formation of product in an earlier step. This type of enzymatic regulation is known as?

287

_ is a competitive inhibitor of succinic dehydrogenase.

288

PMC Practice Test 5 2021

Enzymes which bring about exchange of a functional group are called:

289

PMC Practice Test 5 2021

Which of the following enzymes present in yeast helps out in fermentation?

290

Glucose is converted into ethanol by the _ enzyme present in yeast.

291

The mechanism of enzyme activation is referred to as?

292

PMC Practice Test 5 2021

The optimal pH for the working of enzymes is?

293

PMC Practice Test 5 2021

The number of models that represent the enzyme-substrate model are?

294

PMC Practice Test 5 2021

In uncompetitive inhibition, the inhibitor binds with:

295

PMC Practice Test 4 2021

The specific site at which substrate is attached on the enzyme and converted into product is called as:

296

PMC Practice Test 4 2021

According to the induced fit model, what happens when an enzyme-substrate complex is formed?

297

PMC Practice Test 4 2021

Which statement is incorrect about the Lock and Key Model?

298

PMC Practice Test 4 2021

Which of the following best describes a coenzyme?

299

Competitive inhibition can be overcome by using:

300

UHS MDCAT 2018

The temperature that promotes the maximum activity of enzymes is referred to as:

301

UHS MDCAT 2018

A non-protein part which is essential for proper functioning of enzyme is called:

302

UHS MDCAT 2018

If the molecule can bind to another site of the enzyme rather than the true active site, it is referred to as:

303

Enzymes are _ in nature.

304

Which one of the following is a non-protein group covalently bonded to a few respiratory enzymes, among others?

305

PMC Practice Test 3 2021

In enzymatic mechanism, the substrate bind to the enzyme active site to produce?

306

PMC Practice Test 2 2021

The optimum pH for the functioning of the enzyme pepsin is?

307

PMC Practice Test 2 2021

If we add more substrate to an already occurring enzymatic reaction and it has no affect on the rate of reaction, the process is called?

308

PMC Practice Test 2 2021

The number of substrate molecules converted into the product by one molecule of enzyme active site per unit time is called?

309

PMC Practice Test 1 2021 PMC Practice Test 1 2022

Urease present in:

310

PMC Practice Test 1 2021 PMC Practice Test 1 2022

Which type of bonds are never formed when a substrate fits into the active site of an enzyme?

311

PMC Practice Test 1 2021 PMC Practice Test 1 2022

In 1959, Koshland proposed which of the following?

312

PMC Practice Test 1 2021 PMC Practice Test 1 2022

Inactive enzyme precursors such as pepsinogen for pepsin are called as:

313

Enzymes work by which of the following?

314

UHS MDCAT 2019

A student of chemical engineering mistakenly engulfed the toxic compound "A" which was a potent inhibitor of a certain enzyme. He was immediately brought to a hospital where the doctor injected, intravenously, substrate "B" to minimize the toxic effect of Compound A. His life was saved from serious damage. The treatment method shows that compound A was a _ inhibitor.

315

UHS MDCAT 2019

The type of energy, reduced by the enzymes, for biological reactions to occur is called the:

316

The temperature at which enzyme activity is maximum is called as_?

317

Reversible inhibitors form weak linkages with which of the following?

318

Enzymes binds with chemical reactant which is known as?

319

Antibodies can be digested by using which of the following types of enzymes?

320

The lock and key model of enzyme action was proposed by:

321

The optimum pH for the enzyme arginase is which of the following?

322

Upon increasing the temperature the shape of enzyme's active site?

323

The effect of competitive inhibitor on enzyme activity is such that it affects which of the following?

324

Enzymes that catalyze hydrolysis:

325

Which of the following statements about enzymes is false?

326

The Induced fit model was introduced by Koshland in which of the following year?

327

A reaction will proceed faster if the activation energy is?

328

The substrate binds to specific region of enzyme called?

329

The energy required to destabilize the existing chemical bond is called as:

330

A/An _ is mostly a non-protein chemical compound that is required for the protein's biological activity.

331

Enzymes are _ that catalyze chemical living organisms and are very specific in their action.

332

Cyanide for enzymes act as:

333

The optimum pH of catalase is:

334

What is true about the induced fit model:

335

The cofactor usually acts as "bridge" between:

336

Optimum temperature for enzymes of human body is:

337

Identify the wrong statements.(a) The substrate binds to active site of enzyme and does not fit into active site(b) The binding of substrate induces the enzyme to alter its shape(c) Chemical bonds of substrate break down not to form new enzyme-product complex(d) The enzyme releases the products of the reaction and runs through catalytic cycle once again

338

Due to the similarity of structure, competitive inhibitors may be selected by the _ site.

339

NUMS MDCAT 2020

Which of the following enzymes is raised in rickets?

340

NUMS MDCAT 2020

During feedback inhibition, which of the following structural part of enzyme is involved?

341

PMDC MDCAT 2020

L - Asparaginase enzyme has been used for the treatment of:

342

Enzymes work by lowering the _ of the reactions they catalyse:

343

Sindh MCAT NTS 2018

The enzyme found in saliva responsible for the digestion of carbohydrates is:

344

Sindh MCAT NTS 2013 DUHS and JSMU

The following reaction occurs in the human alimentary canal. What is the enzyme and the product?

345

Sindh MCAT NTS 2012 DUHS and JSMU

An enzyme increases the speed of a reaction:

346

Sindh MCAT NTS 2011 DUHS and JSMU

Which of the following factors affect enzyme activity?

347

Enzymes that are functioning within the cell are called:

348

The enzyme in breast milk that causes the coagulation of milk or forms precipitates of milk is:

349

PMC Practice Test 2 2021

An activated enzyme made of polypeptide chain and a cofactor is?

350

The structure of an enzyme is altered by which of the following inhibitors?

351

The following statements are about enzymes: 1. They are globular proteins except ribo-enzyme.2. They can be inhibited3. They are formed in the smooth endoplasmic reticulum 4. There are only found attached to Plasma membranes in the cell Which statements are correct for all enzymes?

352

The inhibitor which closely resembles the substrate in its molecular structure and inhibits the enzyme activity by binding to the active site of the enzyme is called:

353

UHS MDCAT 2019

An example of competitive inhibition of an enzyme is the inhibition of:

354

Denaturation of enzymes usually occurs at:

355

_____________ does not change substrate affinity for the enzyme:

356

If we increase the concentration of genuine substrate succinic acid then:

357

If concentration of melonic acid increases, then concentration of fumaric acid:

358

Melonic acid is a competitive inhibitor of:

359

___________ after the globular structure of enzyme, but don't destroy:

360

Non-competitive inhibitor binds with enzyme other than active site called:

361

___________ can be removed from increase in concentration of genuine substrate:

362

___________ are structurally similar to the substrate and bind with binding sites.

363

Irreversible inhibitors occupy the active site of an enzyme by forming:

364

Globular structure of an enzyme is destroyed during:

365

All of the followings are inhibitors, except:

366

____________ is a chemical substance which can react with the enzyme but is not transformed into products:

367

Products formed as a result of enzymatic reaction may accumulate and enzymatic reaction may:

368

Time required for completion of an enzyme reaction __________ with _________ in temperature from its optimum:

369

Which of the following works at its best at heightest range of pH:

370

Which enzyme can work at maximum rate in acidic pH?

371

Optimum pH for enterokinase is:

372

Bonds breakage in enzymes and denaturation of enzymes can be due to:

373

A slight change in pH may result in:

374

Rate of reaction becomes double for every ___________ C rise in temperature:

375

What happens at the time of denaturation of enzyme:

376

At freezing point activity of enzyme is:

377

At very high temperature, when globular structure of enzyme is lost it is said to be:

378

In human body optimum temperature for all enzymes is:

379

All enzymes can work at their maximum rate at a specific temperature called:

380

Enzyme Rubisco follows which one?

381

Lock and key model was modified by:

382

Active site is rigid structure according to:

383

Most enzymes do not float about in a kind of cytoplasmic soup, but are attached to membrane system inside the cell, in ___________.

384

Enzymes require _________ medium for their activity:

385

_____________ catalyzes the transformation of substrate into products:

386

Active site of the enzyme is made up of:

387

Number of polypeptide chains in an enzyme:

388

Charge and shape of active site is formed by:

389

Enzymes lower the activation energy by all means except:

390

Activator resembles with co-enzymes in all aspects, except:

391

Enzymes lower the ___________ of the reaction.

392

All enzymes are:

393

Enzymes involved in synthesis of proteins are integral part of:

394

Most of the enzymes are simple and present in ____________ of cell.

395

Which of the following exist in activated form?

396

Enzyme with its co-enzyme or prosthetic group removed, is designated as:

397

If non-protein part is covalently bonded with enzyme, it is known as:

398

Which one is being used as co-enzyme?

399

In organic, detachable cofactor is:

400

Which one of the following is not related to co-factor:

401

Non-protein part of an enzyme is known as:

402

Catalytic activity is restricted to a small portion of enzyme, known as:

403

___________ are biological catalyst which are protein in nature:

404

Which one is odd in given list?

405

All of the following are fibrous proteins except:

406

Glycosidic linkage is present in all of the following except:

407

Animals store carbohydrates in the form of:

408

Number of nucleotides present in insulin gene:

409

It is most diverse biological molecule:

410

The most abundant compound found in Gram negative bacteria:

411

Number of heme units in hemoglobin:

412

Most abundant compounds to be found inside the cell:

413

One of the following is not common in eukaryotes:

414

The sugar present in ATP is:

415

It can be soluble in hot water:

416

All carbon atoms in a monosaccharide have a hydroxyl group except one. This carbon is actually:

417

In phosphatidic acid, phosphoric acid is attached with:

418

It is also called as neutral lipid:

419

A structural of cell comparable to organ of body is:

420

Vaccination can be used against:

421

During translation, amino acids are arranged in proper sequence according to sequence of nucleotides present in:

422

Structurally, which of the following is different from others?

423

A tissue specialized for secretion is:

424

An example of macromolecule is:

425

They are widespread in bacterial, animal and plant cells and are associated with membranes:

426

Lipids are usually non-polymers. The only polymers found in lipids are included in:

427

Lipid store high amount of energy because of higher proportion of:

428

The main source of carbohydrates for animal is:

429

Polysaccharides are:

430

General formula of carbohydrate is:

431

The covalent bond between two monosaccahrides is:

432

Estrogen, cholesterol and other steroids are examples of:

433

Saturated fatty acids have double bonds:

434

These are esters of fatty acids and glycerols:

435

It is an axample of non-reducing sugar:

436

From biological point of view, most important hexose is:

437

Minimum number of carbons that can be found in any carbohydrate is:

438

An important sugar occurring only in animals is:

439

It is not true for carbohydrates:

440

It is not a carbohydrate:

441

The principal source of energy for the body is:

442

Isoprenoid units through condensation gives rise to:

443

Sucrose on hydrolysis yields:

444

Cloning is an example of:

445

Vaccination is an example of:

446

Transgenic plants are obtained through:

447

Organs formation in highly complex form is developed in:

448

Plasmodium causes malaria and complete its life cycle in two hosts. Study of its life cycle is:

449

Phospholipids are derivatives of phosphatidic acid. Phosphatidic acid contains all of the following except:

450

Acyl glycerols are formed by reaction between fatty acid and alcohol. This reaction involves:

451

The example of unsaturated fatty acid is:

452

In phospholipids molecules, which part forms tail:

453

The glycosidic linkage found in glucose is:

454

The chief form of carbohydrates stored in animals and found abundantly in liver and muscle cells is:

455

All of the following are aldo sugars except:

456

Most abundant organic compound on a cell is:

457

The isolation of normal gene and its insertion into the host by using bone marrow cells for treatment of a disease is known as:

458

First vaccine was developed against:

459

Control of pests by using some living organisms is known as:

460

Parts of food digested in stomach are:

461

___________ is present in all cells whether prokaryotic or eukaryotic cells.

462

A group of similar cells that perform the same function:

463

Cytoplasmic streaming can be studied under__________.