Biology 251-300 MCQs

Biology

251. Which of the following combinations is an example of self replicating organelles?

a. Mitochondria Ribosomes

b. Mitochondria Nucleus

c. Mitochondria Chloroplast

d. Mitochondria Vacuole

252. Which of the following is an autosomal disorder __________?

a. Down's syndrome

b. Klinefelter's syndrome

c. Turner's syndrome

d. Jacob's syndrome

253. Embryonic induction is caused by part developing from _________?

a. Endoderm

b. Ectoderm

c. Mesoderm

d. Extraembryonic layers

254. Sickle cell anemia is an example of _________?

a. Chromosomal aberration

b. Insertion of gene

c. Deletion of gene

d. Point mutation

255. The type of plastids which help in pollination is _________?

a. Chromoplasts

b. Leucoplasts

c. Chloroplasts

d. All of these

256. Purines and pyrimidines re in equal ratio in DNA. It was indicated by _________?

a. Friedrich Miescher

b. Chargaff

c. Watson & Crick

d. Hershey & Chase

257. Chlorophyll is a/an ________ molecule?

a. Inorganic

b. Cationic

c. Anionic

d. Organic

258. Ribonucleoprotein particles are the name of _________?

a. DNA

b. Nucleus

c. Eukaryotic ribosomes

d. RNA

259. Lock and Key model was proposed by _________?

a. Emil Fischer

b. Edward Koshland

c. Robin Williams

d. Rudolph Virchow

260. Which step causes activation of catalytic site of an enzyme __________?

a. Change in pH of the surroundings

b. Formation of Enzyme Substrate Complex

c. Change in the charge of the active site

d. Change in temperature

261. Amoeboid movements and movement of cyclosis is due to ________?

a. Microfilaments

b. Microtubules

c. Intermediate filaments

d. Cytoskeleton

262. Enzymes ________ the activation energy of a chemical reaction?

a. Increases

b. Decreases

c. Does not effect

d. Increases or decreases depending upon individual enzyme

263. Which one forms the raw material for coenzymes _________?

a. Vitamins

b. Carbohydrates

c. Proteins

d. Metals

264. Proteins and lipids are converted into glycolipids and glycoproteins by adding carbohydrates by _________?

a. Ribosomes

b. Cytoplasm

c. Golgi apparatus

d. Endoplasmic reticulum

265. Biological molecules (proteins) which catalyze a biochemical reaction and remain unchanged after completion of reaction are called _________?

a. Cofactor

b. Coenzyme

c. Activator

d. Enzymes

266. In which of the following location enzymes controlling cellular respiration are present ________?

a. Nucleus

b. Chloroplast

c. Mitochondria

d. Ribosome

267. In Golgi apparatus the maturing face is ________?

a. Biconcave

b. Convex

c. Spherical

d. Concave

268. A cofactor made of inorganic ion which is detachable is called _______?

a. Prosthetic group

b. Coenzyme

c. Activator

d. Cofactor

269. An activated enzyme consisting of polypeptide chain and a cofactor is called ________?

a. Apoenzyme

b. Holoenzyme

c. Activated enzyme

d. Both b & c

270. Centrioles are composed of ________ triplets of microtubules.

a. 3

b. 9

c. 10

d. 15

271. Which statement about enzyme is incorrect __________?

a. Some of them consist solely of protein with no non protein part

b. They catalyze a chemical reaction without being utilized

c. All enzymes are fibrous proteins

d. They without their cofactor are called apoenzyme

272. A three dimensional activity bearing a specific charge by which the enzyme reacts with its substrate is called ________?

a. Active site

b. Binding site

c. Catalytic site

d. Allosteric site

273. Cellular organelles related with H2O2 are _______?

a. Glyoxisomes

b. Lysosomes

c. Peroxisomes

d. Ribosomes

274. If more substrate to already occurring enzymatic reaction is added more enzyme activity is seen because ________?

a. There is probably more substrate present than there is enzyme

b. There is probably more enzyme available than there is substrate

c. There is probably more product present than there is either substrate or enzyme

d. The enzyme substrate complex is probably failing to form during the reaction

275. A group of ribosomes attached to mRNA is known as _________?

a. Polymer

b. Polypeptide

c. Polysomes

d. Monomer

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

a. Increase in enzyme molecule increases the available active sites

b. This relation is for unlimited time period with unlimited enzyme concentration

c. If the concentration is doubled the rate will become two fold

d. None of these

277. Which statement is incorrect about Lock and Key Model _________?

a. Specific enzyme can transform only a specific substrate

b. Active site of an enzyme is a non flexible structure

c. Active site does not change before during or even after the reaction

d. It explains the mechanism of every chemical reaction

278. If the concentration of enzyme is kept constant and amount of substrate is increased a point is reached where increase in substrates concentration does not affect the reaction rate because of __________?

a. Enzymes get denatured at higher substrate concentration

b. Rate of reaction is indirectly proportional to substrate concentration at this point

c. All the active sites on enzyme molecule are occupied

d. None of these

279. The active site of an enzyme _________?

a. Never changes

b. Forms no chemical bond with substrate

c. Determined by structure and the specificity of the enzyme

d. They are non specific in their action

280. Factory of Ribosomal synthesis is ________?

a. Cytoplasm

b. Nucleus

c. Nucleolus

d. Endoplasmic reticulum

281. If more substrate to already occurring enzymatic reaction is added and there is no effect on the rate of the reaction what is the form given to this situation ________?

a. Saturation

b. Denaturation

c. Composition

d. Inhibition

282. Who opposed the idea the cell is an empty space bounded by thick wall?

a. Lorenz Oken

b. Schwann

c. Robert Brown

d. Rudolph Virchow

283. Extreme change in pH results in ________?

a. Change in ionization of amino acids at the active site of the enzyme

b. Change in the ionization of the substrate

c. Denaturation of the enzyme

d. Increase in the reaction rate

284. Resolution power of a compound microscope is ________?

a. 2.0 micro m

b. 2-4 A

c. 24 micro m

d. 24 A

285. Excessive increase in temperature of medium causes the enzyme molecule to _________?

a. Activate

b. Unaffected

c. Denatured

d. None of these

286. If enzyme concentration is low than substrate pH and temperature values are equal to requirement then which of the following will increase rate of reaction _________?

a. increase in concentration of enzyme

b. increase in concentration of substrate

c. increase in pH

d. increase in temperature

287. In cell fractionation various components of cells including its organelles can be isolated in different layers depending upon _________?

a. Their physical properties like size & weight

b. Physical properties of the medium like its density

c. Their electrical properties like their charges

d. Both a & b

288. The structure of an enzyme is altered by _________?

a. Irreversible inhibitor

b. Reversible inhibitor

c. Competitive inhibitor

d. Non-competitive inhibitor

289. Malonic acid is an example of ________?

a. Irreversible inhibitor

b. Reversible inhibitor

c. Competitive inhibitor

d. Non-competitive inhibitor

290. Magnifying power of electron microscope as compared to eye is _________?

a. 500X

b. 250000X

c. 500000X

d. 250X

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

a. Competitive inhibitors

b. Non-competitive inhibitors

c. Irreversible inhibitors

d. Both a and b

292. Which of the statement about cell membrane is not true?

a. It contains protein molecules embedded in lipid bilayer

b. It is a differentially permeable membrane

c. It contains charged pores thus ions being charged particles cross cell membrane much easier than neutral particles

d. It may get unfolded to engulf solid or liquid material

293. A substance which binds at the active site of the enzyme but does not result in the formation of the products is called _________?

a. Irreversible inhibitor

b. Reversible inhibitor

c. Competitive inhibitors

d. Non-competitive inhibitors

294. 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 ________?

a. Co-enzyme

b. Blocker

c. Inhibitor

d. Cofactor

295. Optimal temperature of enzymes present in human body is _________?

a. 27 degree C

b. 37 degree C

c. 47 degree C

d. 30 degree C

296. Strengthening material of prokaryotic cell wall is ________?

a. Cellulose

b. Chitin

c. Inorganic salts silica waxes and lignin

d. Peptidoglycan or Murein

297. Spherical or tubular membranes which separate the material present in endoplasmic reticulum from that of cytoplasmic material are called ________?

a. Cytosol

b. Cisternae

c. Polysomes

d. Cristae

298. Which is not the function of endoplasmic reticulum?

a. Nerve impulse conduction

b. Transport of material

c. Mechanical support

d. Synthesis of conjugated molecules

299. 60S and 40S subunit combine to form _________ particle.

a. 100 S

b. 90 S

c. 80 S

d. 70 S

300. Pancreas produces secretory granules that help in digestion. These granules after passing through endoplasmic reticulum are pinched off from _________ surface of Golgi apparatus:

a. Forming face

b. Maturating face

c. Any of them

d. None of these