Saturday, September 29, 2012

enzymes


1: At about 0 C, most enzymes are
(A) Inactive
(B) Active
(C) Destroyed
(D) Replicated
2: Vitamins are essential to the survival of organisms because vitamins usually function as
(A) Substrates
(B) Nucleic acids
(C) Co-enzymes
(D) Nucleosides
3:When a molecule binds to an area of an enzyme that is not the active site, and changes the shape of the enzyme so that it no longer can work, this is called
(A) denaturation
(B) competitive inhibition
(C) noncompetitive inhibition
(D) substrate delocation
4: What is a coenzyme?

(A) Inorganic ion
(B) Organic molecule
(C) Both A and B
(D) None of these
5: Which statement best expresses the information represented in the graph shown?

(A) The action of enzymes varies with pH
(B) A pH of 7 provides the optimum environment for digestive enzymes
(C) Gastric juice is active at a pH extending from 0 to 12
(D) Acids have a pH greater than 7
6: Which type of inhibitor is shown in this diagram?

(A) Competitive 
(B) Non-competitive
(C) Allosteric 
(D) Both B and C

7: Which enzyme represents an enzyme functioning in this reaction?
(A) E 
(B) C
(C) B 
(D) A
Answer key
1.A, 2.C, 3.C, 4.B, 5.A, 6.D, 7.C
++++++++++++++++++++++++++++++++
1: What is a cofactor?
(A) Inorganic ions
(B) Organic molecules
(C) Both a and b
(D) None of the above
2: Mg+2 is an inorganic activator for the enzyme
(A) Phosophatase
(B) Carbonic anhydrase
(C) Enterokinase
(D) Amylase
3: Zn+2 is an inorganic activator for enzyme.
(A) Carbonic anhydrase
(B) Phosophatase
(C) Chymotrypsin
(D) Maltase
4: Which antibiotic blocks the active site of an enzyme that many bacteria used to make cell-walls.
(A) Amphotericin
(B) Gentamicin
(C) Penicillin
(D) Cephalosporin
5: DDT and Parathion are inhibitors of key enzymes in
(A) Nervous system
(B) Respiratory system
(C) Digestive system
(D) Circulatory system
6: At high temperature the rate of enzyme action decreases because the increased heat
(A) Changes the pH of the system
(B) Alters the active site of the enzyme
(C) Neutralize acids and bases in the system
(D) Increases the concentration of enzymes
7: Which of the following enzymes would digest a fat?
(A) sucrase
(B) protease
(C) Ligase
(D) lipase
8: In the Lock and Key model of enzyme action, the part of the enzyme that recognizes the substrate is known as the
(A) Enzyme-substrate complex
(B) Product
(C) Enzyme-product complex
(D) Active site
9: Which model of enzyme action is represented in this diagram.
(A) Fluid mosaic model
(B) Induce fit model
(C) Lock and key model
(D) Reflective index model
10: A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation? 

(A) Starch molecules are too large to be hydrolyzed
(B) Enzyme molecules are specific in their actions
(C) Egg white acts as a coenzyme for hydrolysis
(D) Starch is composed of amino acids.
 Answer key
1.C, 2.A, 3.A, 4.C, 5.A, 6.B, 7.D, 8.D, 9.C, 10.B
+++++++++++++++++++++++++++++++++++++
1: Which one is not attribute of enzyme
(A) Specific in nature
(B) Protein in chemistry
(C) Consumed in reaction
(D) Increases rate of reaction
2: Which one inactivates an enzyme by indirectly changing the shape of the active site of an enzyme

(A) Non-competitive inhibitor
(B) Competitive inhibitor
(C) Coenzyme
(D) Activator
3: The enzymes are classified into
(A) Five groups
(B) Three groups
(C) Six groups
(D) Four groups
4: Non-proteinaceous part of holoenzyme is
(A) Prosthetic group
(B) Apoenzyme
(C) Tubulin
(D) None of these
5: Enymes are highly specific for a given substrate which is due to the shape of their
(A) Active site
(B) Allosteric site
(C) Non-competitive site
(D) None of these
6: The name enzyme was suggested in 1878 by the German physiologist
(A) Wilhelm Kuhne
(B) Koshland
(C) Fischer
(D) Paul Filder
7: Proteinaceous part of holoenzyme is
(A) Prosthetic group
(B) Apoenzyme
(C) Lecithin
(D) None of these
8: The “lock and key hypothesis” attempts to explain the mechanism of
(A) vacuole formation
(B) pinocytosis
(C) sharing of electrons
(D) enzyme specificity
9: An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are
(A) hydrolytic
(B) specific
(C) catalytic
(D) synthetic
10: The site where enzyme catalyzed reaction takes place is called?
(A) Active site
(B) Allosteric site
(C) Denatures site
(D) Dead Site
Answer key
1.C, 2.A, 3.C, 4.A, 5.A, 6.A, 7.B, 8.D, 9.B, 10.A
++++++++++++++++++++++++++++++++++++++
1: A catalyst is a chemical involved in, but not ____________ by, a chemical reaction.
(A) Supported
(B) Changed
(C) Controlled
(D) All of these
2: Many enzymes function by __________________ the activation energy of reactions.

(A) Increasing 
(B) Promoting
(C) Lowering 
(D) Both A and B

3: An uncatalysed reaction requires a

(A) Higher activation energy 
(B) Lower activation energy
(C) Balanced activation energy 
(D) All of these

4: It suggests that the binding of the substrate to the enzyme alters the structure of the enzyme, placing some strain on the substrate and further facilitating the reaction.

(A) Lock and Key hypothesis 
(B) Induced fit hypothesis
(C) Fischer’s hypothesis 
(D) D.D. Wood’s hypothesis

5: They are non-protein organic molecules bound to enzymes near the active site.

(A) Activators 
(B) Coenzymes
(C) Holoenzymes 
(D) All of these

6: The first step in any reaction catalysed by an enzyme is the formation of a specific association between the molecules called an

(A) Enzyme-product complex 
(B) Enzyme-intermediate complex
(C) Enzyme-substrate complex 
(D) None of these

7: The function of competitive inhibitors is defined by their ability to interact or bind to

(A) The active site of an enzyme 
(B) Regulatory sub-units of an enzyme
(C) Non-competitive inhibitor 
(D) Enzyme cofactors 

8: If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be
(A) Add more of the enzymes
(B) Add more substrate
(C) Add an allosteric inhibitor
(D) Add a non-competitive inhibitor
9: During _____________ the final product of a metabolic pathway turn off the first step of metabolic pathway.
(A) Positive feed back
(B) Negative feed back
(C) Competitive feed back
(D) Both A and C
10: _____________ occurs when the inhibitory chemical, which does not have to resemble the substrate, binds to the enzyme other than at the active site.
(A) Noncompetitive Inhibition 
(B) Competitive Inhibition 
(C) Uncatalysed reaction 
(D) All A, B and C

Answer Key
1.B, 2.C, 3.A, 4.B, 5.B, 6.C, 7.A, 8.A, 9.B, 10.A
++++++++++++++++++++++++++++++++++++++
1: The enzyme minus its coenzyme is referred to as the
(A) Iso-enzyme
(B) Metalloenzyme
(C) Apoenzyme
(D) All of these
2: The “lock and key” model of enzyme action illustrates that a particular enzyme molecule
(A) forms a permanent enzyme-substrate complex 
(B) may be destroyed and resynthesized several times 
(C) interacts with a specific type of substrate molecule 
(D) reacts at identical rates under all conditions
3: Consider this reaction. A + B –> C + D + energy. 

(A) This reaction is exergonic 
(B) An enzyme could still speed the reaction 
(C) A and B are reactants; C and D are products 
(D) All of these are correct
4: An inhibitor that changes the overall shape and chemistry of an enzyme is known as a(n)

(A) Auto-steric inhibitor 
(B) Competitive inhibitor
(C) Steric inhibitor 
(D) Noncompetitive inhibitor

5: Non-protein components of enzymes are known as

(A) Coenzymes 
(B) Activators
(C) Cofactors 
(D) All A, B, and C

6: The reaction below occurs within the cells to prevent the accumulation of hydrogen peroxide. In this reaction, catalase functions as an
(A) Enzyme in the breakdown of hydrogen peroxide
(B) Enzyme in the synthesis of hydrogen peroxide
(C) Emulsifier in the digestion of hydrogen peroxide
(D) Indicator in the detection of hydrogen peroxide
7: An enzyme is generally named by adding ________ to the end of the name of the ____________.
(A) “-ase”. coenzyme
(B) “-ase”. cell in which it is found
(C) “-ose”. substrate .
(D) “-ase”. substrate
8: The minimum amount of energy needed for a process to occur is called the
(A) Minimal energy theory
(B) Process energy
(C) Kinetic energy
(D) Activation energy
9: A student conducts an experiment to test the efficiency of a certain enzyme. Which would probably not result in a change in the enzyme’s efficiency?
(A) Adding an acidic solution to the setup
(B) Adding more substrate but not enzyme
(C) Increasing temperature of solution
(D)All a, b, & c change enzyme’s efficiency
10: Enzymes function as
(A) Organic catalysts
(B) Inorganic catalysts
(C) Inhibitors
(D) All of these
Answer
1.C, 2.C, 3.D, 4.D, 5.D, 6.A, 7.D, 8.D, 9.D, 10.A
++++++++++++++++++++++++++++++++++++
Q:1: The catalytic activity of an enzyme is restricted to its small portion called

(A) Active site 
(B) Passive site
(C) Allosteric site 
(D) All Choices are correct

Q:2: An activated enzyme made of polypeptide chain and a co-factor is

(A) Coenzyme 
(B) Substrate
(C) Apoenzyme 
(D) Holoenzyme

Q:3: Koshland in 1959 proposed

(A) Fluid mosaic model 
(B) Induce fit model
(C) Lock and key model 
(D) Reflective index model

Q:4: Enzymes are largely _________________________ in their chemical nature.

(A) Lipids 
(B) Steroids
(C) Proteinaceous 
(D) All A, B and C 

Q:5: Who proposed “lock and key” model to study enzyme – substrate interaction?
(A) Koshland (1959)
(B) Wilhelm Kuhne (1878)
(C) Fischer (1898)
(D) None of these
Q:6: In human body the optimum temperature for enzymatic activities is
(A) 37oC
(B) 40oC
(C) 25oC
(D) 30oC
Q:7: Optimum pH value for pepsin is
(A) 5.5
(B) 7.4
(C) 4.1
(D) 1.4
Q:8: Competitive inhibitors stop an enzyme from working by
(A) Changing the shape of the enzyme
(B) merging with the substrate instead
(C) blocking the active site of the enzyme
(D) combining with the product of the reaction
Q:9: The enzymes are sensitive to
(A) Changes in pH
(B) Changes in temperature
(C) Both A and B
(D) None of these
Q:10: Enzyme B requires Zn2+ in order to catalyze the conversion of substrate X. The zinc is best identified as a(n):
(A) Coenzyme
(B) Activator
(C) Substrate
(D) Product
Answer key
1.A, 2.D, 3.B, 4.C, 5.C, 6.A, 7.D, 8.C, 9.C, 10.B
+++++++++++++++++++++++++++++++++++++++++
1. Which of the following chemotherapeutic agents works by impairing de novo purinesynthesis?
(a) acyclovir (acycloguanosine)
(b) 5-fluorouracil (antimetabolite)
(c) methotrexate (anti folate)
(d) hydroxyurea
2. The largest energy reserve (in terms of kilocalories) in humans is:
(a) liver glycogen
(b) muscle glycogen
(c) adipose tissue triacylglycerol.
(d) muscle protein.
3. In the interaction of a hormone with its receptor all of the following are true EXCEPT:
(a) more than one polypeptide chain of the hormone may be necessary.
(b) more than one second messenger may be generated.
(c) an array of transmembrane helices may form the binding site for the hormone.
(d) hormones released from their receptor after endocytosis could theoretically interact with a nuclear receptor.
4. Some hormone-receptor complexes are internalized by endocytosis. This process may involve:
(a) binding of hormone-receptor complex to a clathrin coated pit.
(b) recycling of receptor to cell surface.
(c) formation of a receptosome.
(d) all of the above
5. In hypopituitarism it is necessary to maintain the ovarian cycle in female patients. In the ovarian cycle:
(a) GnRH enters the vascular system via transport by a specific membrane carrier.
(b) corpus luteum rapidly involutes only if fertilization does not occur.
(c) inhibin works by inhibiting synthesis of a subunit of FSH.
(d) LH is taken up by corpus luteum and binds to cytoplasmic receptors.
6. All of the following statements about actin and myosin are true EXCEPT:
(a) the globular head section of myosin has domains for binding ATP and actin.
(b) actin is the major protein of the thick filament.
(c) the binding of ATP to the actin-myosin complex promotes dissociation of actin and myosin.
(d) F-actin, formed by aggregation of G-actin-ATP-MgH complex, is stabilized when tropomyosin is bound to it.
7. Starch digestion is more efficient after heating the starch with water because heating:
(a) hydrates the starch granules, making them more susceptible to pancreatic amylase.
(b) partly hydrolyses a-1, 6 links.
(c) converts the linear amylose to branched amylopectin, which resembles glycogen.
(d) inactivates amylase inhibitors, which are common in the tissues of starchy plants.
8. Micelles:
a) are the same as emulsion droplets.
(b) form from bile acids at all bile acid concentrations.
(c) although they are formed during lipid digestion, do not significantly enhance utilization of dietary lipid.
d) always consist of only a single lipid species.
9. Certain tissues effect Cl– secretion via a Cl– channel (CFTR protein-cystic fibrosis transmembrane regulatory protein). Cholera toxin abnormally opens the channel leading to a loss of NaCl. Treatment for cholera and sports drinks for electrolyte replacement are fluids high in Na+ and glucose. The presence of glucose enhances NaCl replenishment because:
(a) absorbing any nutrient causes Na+ uptake.
(b) glucose prevents Na+ excretion.
(c) Na+ and glucose are transported in opposite directions.
(d) glucose is absorbed across intestinal epithelial cells via a Na+ -dependent cotransporter.
10. Of two people with approximately the same weight, the one with the higher basal energy requirement would most likely be:
(a) taller
(b) female if the other were male.
(c) older
(d) under less stress.









------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------
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Bio-molecules


1. The simplest amino acid is
a)Glycine    b)Lysine   c)Tyrosine   d)Aspartic acid
2. A source of maximum energy is
a)Carbohydrate    b)Fat   c)Protein   d)Vitamins
3. Besides nucleus, DNA is also present in
a)Mitochondria    b)Lysosomes   c)Golgi apparatus   d)Ribosomes
4. Purines of RNA are
a)Guanine and adenine    b)Uracil and thymine   c)Adenine and cytosine   d)Uracil and guanine
5. Structure of DNA was given by
a)Kornberg    b)Nirenberg   c)Watson and Crick   d)Holley and Nirenberg
6. Cellulose is
a)Hexosan polysaccharide    b)Pentosan polysaccharide   c)Heptopolysaccharide   d)Heteropolysaccharide
7. Proteins were named by
a)Berzelius    b)Sanger   c)Fleming   d)Dujardin
8. Purine bases of DNA are
a)A and G    b)A and C   c)C and T   d)A and U
9. Bond present between two nucleotides of a polynucleotide is
a)Covalent bond    b)Hydrogen bond   c)Phosphodiester bond   d)high energy phosphate bond
10. The protein part of enzyme is
a)Prosthetic group    b)Apoenzyme   c)Holoenzyme   d)Zymogen
Answer
1a,2b,3a,4a,5c,6a,7a,8a,9c,10b

****************************************


1: Water molecule has characteristics of
(A) Acid
(B) Base
(C) Both acid and base
(D) None of these
2: The amount of heat must be absorbed or lost by 1g of that substance to change its temperature by 1 C°
(A) Specific heat
(B) Heat of vaporization
(C) Both A and B
(D) None of these
3: During the conversion of ATP into ADP __________ energy is released.
(A) 31.81 KJ / mole
(B) 7.3 K.Cal / mole
(C) 61.8 KJ / mole
(D) Both A and B.
4: Molecular formula of Stearin fat is
(A) C57 H110 O6
(B) C57 H98 O6
(C) C57 H104 O8
(D) C57 H104 O6
5: The carbohydrate molecule which yield 2 to 10 monosaccharide molecules on hydrolysis are
(A) Polysaccharides
(B) Oligosaccharides
(C) Monosaccharides
(D) Heterosaccharides
6: It is estimated that a person of average size contains 16 Kg of fat which is equivalent to
(A) 244000 K.Cal of energy
(B) 164000 K.Cal of energy
(C) 144000 K.Cal of energy
(D) 188000 K.Cal of energy
7: The four interconnected rings of steroid molecule have total
(A) 12 carbon
(B) 15 carbon
(C) 16 carbon
(D) 17 carbon
8: ATP is an example of
A) Mononucleotide
(B) Dinucleotide
(C) Polynucleotide
(D) None of these
9: The process of making a polypeptide sequence from the genetic code of mRNA molecule associated with a ribosomes termed as
(A) Transduction
(B) Translation
(C) Transformation
(D) Transcription
10: NAD is an example of
(A) Mononucleotide
(B) Dinucleotide
(C) Coenzyme
(D) Both B and C

Answer
1. C, 2. A, 3. D, 4. A, 5. B, 6. C, 7. D, 8. A, 9. B, 10. D
*********************************************************
1: Waxes from protective coating on
(A) Leaves
(B) Fruits
(C) Animal’s skin
(D) All of these
2: The four nitrogenous bases which form the code words for DNA language are
(A) ACTU
(B) UTAC
(C) AGTU
(D) AGCT
3: DNA and RNA differ in
(A) Sugar only
(B) Sugar and purines
(C) Sugar and pyrimindines
(D) Sugar & phosphate
4: A bond formed between carboxylic acid and alcohol is
(A) Ester bond
(B) Amide bond
(C) Phosphate bond
(D) Ionic bond
5: When amino acids in a polypeptide chain are arranged in spiral manner, it is called
(A) Primary structure
(B) Secondary structure
(C) Tertiary structure
(D) Quaternary structure
6: The step of protein synthesis in which the information contained specific segment of DNA is copied into RNA is called
(A) Transduction
(B) Translation
(C) Transformation
(D) Transcription
7: Choose the pair of terms that completes this sentence
Nucleotides are to __________as ____________ are proteins.
(A) Aminoacids______Polypeptides
(B) Genes _______ Enzymes
(C) Nucleic acids _____ Amino acids
(D) Polymers _____ Peptides
8: Which of these terms includes all others in the list
(A) Nucleic acid
(B) Purine
(C) Nucleotide
(D) Nitrogenous base
9 The compounds made up of simple repeating isoprenoid units are called
(A) Neutral lipids
(B) Terpenoids
(C) Waxes
(D) All of these
10: The term Protein was coined by
(A) Berzelius
(B) G.J. Murlder
(C) Bloor
(D) T.H. Morgan
Answer
1. D,2. D,3. C,4. A,5. B,6. D,7. C,8. A,9. B,10. A,
***************************************************************
1: Which of these is NOT a function of lipids?
(A) Long term energy storage
(B) Structures in cells
(C) Sex hormones
(D) Enzymes
2: All living things use the same ___ amino acids.
(A) 4
(B) 20
(C) 100
(D) 64
3: Which of these is NOT a nucleotide base found in DNA?
(A) Uracil
(B) Adenine
(C) Guanine;
(D) Thymine
4: ATP consists of the ____________________, ribose sugar, , and phosphate group, PO4-2) plus two otherphosphate groups.
(A) Cytosine base
(B) Guanine base
(C) Thymine base
(D) Adenine base
5: Membrane carbohydrates when linked to lipids are called
(A) Sphingolipids
(B) Glycolipids
(C) Phospholipids
(D) Sterols
6: Lactose is present in
(A) Sugar cane
(B) Fruits
(C) Milk
(D) Egg
7: A disaccharide that gives two molecules of glucose on hydrolysis is
(A) Sucrose
(B) Lactose
(C) Maltose
(D) None of these
8: In sugar cane and sugar beet, the storage product is
(A) Maltose
(B) Sucrose
(C) Lactose
(D) Isomaltose
9: One molecule of glucose and one molecule of galactose form
(A) Maltose
(B) Sucrose
(C) Lactose
(D) Isomaltose
10: Nucleic acids are related with
(A) Respiration
(B) Photosynthesis
(C) Heredity
(D) None of these
Answer
1. D,2. B,3. A,4. D,5. B,6. C,7. C,8. B,9. C,10. C
********************************************************************
1: It is an animal storage product that accumulates in the vertebrate liver and muscles.
(A) Cellulose
(B) Chitin
(C) Glycogen
(D) Fructose
2: Asymmetrical lipid molecules with a hydrophilic head and a hydrophobic tail, with a phosphate group in place of one of the three fatty acid chains.
(A) Wax
(B) Terpenoid
(C) Steroid
(D) Phospholipid
3: Triglycerides that are solid at room temperature.
(A) Fats
(B) Oils
(C) Linoleic acid
(D) None of these
4: Triglycerides that are liquid at room temperature.
(A) Fats
(B) Oils
(C) Stearin
(D) All of these
5: A chemical group composed of a central phosphorous bonded to four oxygen.
(A) Carbonyl group
(B) Sulfhydryl group
(C) Carboxylic
(D) Phosphate group
6: Nucleic acids are polymers composed of monomer units known as
(A) Amino acids
(B) Nucleosides
(C) Nucleotides
(D) Nitrogenous bases
7: There are __________ nitrogenous bases.
(A) Four
(B) Five
(C) Six
(D) Three
8: The form of RNA that delivers information from DNA to be used in making a protein is _______________.
(A) messenger RNA
(B) ribosomal RNA
(C) transfer RNA
9: RNA occurs in
(A) Nucleus
(B) Cytoplasm
(C) Both A and B
(D) Nucleoplam
10: The monomer that makes up polysaccharides is
(A) Amino acids
(B) Glucose
(C) Fatty acids
(D) Glycerol
Answer
1. C,2. D,3. A,4. B,5. D,6. C,7. B,8. A,9. C,10. B
*************************************************************
1: The functional group –COOH is
(A) Acidic
(B) Basic
(C) Never ionized
(D) All options are correct
2: Which of these is an example of hydrolysis
(A) Amino acid + amino acid – Dipeptide + H2O
(B) Dipeptide + H2O—amino acid + amino acid
(C) Both A and B
(D) Neither of these is correct
3: A fatty acid is unsaturated if it
(A) Contains hydrogen
(B) Contains double bonds
(C) Contains an acidic group
(D) Bonds to glycogen
4: A hormone is an example of which functional class of proteins.
(A) Contractile
(B) Structural
(C) Regulatory
(D) Cyclic
5: The Sugar found in RNA is
(A) Fructose
(B) Galactose
(C) Deoxyribose
(D) Ribose
6: Steroid are classified as
(A) Carbohydrates
(B) Lipids
(C) Proteins
(D) Nucleic acids
7: Hemoglobin is an example of which functional class of protein
(A) Contractile
(B) Structural
(C) Regulatory
(D) Transportive
8: In RNA the Nitrogen base that takes the place of thymine is
(A) Adenine
(B) Cytosine
(C) Uracil
(D) Guanine
9: The Suffix that denotes a sugar is
(A) ase
(B) ose
(C) ide
(D) amide
10: Two different molecule belonging to different categories, usually combine together to form
(A) Homomer molecule
(B) Macro molecule
(C) Conjugated molecule
(D) All options are correct
Answer
1. A,2. B,3. B,4. C,5. D,6. B,7. D,8. C,9. C,10. C
***************************************************************
1: A bond that forms between a positively charged hydrogen atom of one molecule and a negative charged region of another molecule is a(n)
(A) Ionic bond 
(B) Hydrogen bond
(C) Covalent bond 
(D) Basic bond
2: Dehydration and hydrolysis reactions involve removing or adding ___________to macromolecule subunits.
(A) CH and NH2 
(B) C and H
(C) -COOH and H 

(D) OH and H
3: A chemical “buffer”
(A) can donate a H+ when the solution becomes too basic
(B) can absorb a H+ when the solution becomes too acidic
(C) is utilized in living systems to maintain correct pH (D) All of the above are correct
4: Nucleotides have a nitrogenous base attached to a sugar at the 
(A) 1’ carbon 
(B) 3’ carbon
(C) 4’ carbon 
(D) 5’ carbon
5: If three molecules of a fatty acid, each having the formula C16H22COOH, were joined to a molecule of glycerol (C3H8O3), the resulting molecule would have the formula
(A) C48H68O6
(B) C48H74O6
(C) C54H71O6 
(D) C54H68O9
6: This aminoacid is called


(A) Glycine
(B) Alanine
(C) Leucine
(D) Valine
7: Monosaccharides contain carbon atoms
(A) 3-7 
(B) 3-6
(C) 3-9 
(D) 3-10
8: Stearin is
(A) Fatty acid 
(B) Saturated acylglycerol
(C) Unsaturated acylglycerol 
(D) None of these
9: Energy absorbed to change water from liquid to gas is called
(A) Latent heat of fusion 
(B) High surface tension
(C) Heat of vaporization 
(D) High heat capacity
10: The sources of carbohydrates are green plants. These are primary product of 
(A) Respiration 
(B) Catabolism
(C) Photosynthesis 
(D) All A, B and C
Answer
1. B, 2. D, 3. D, 4. A, 5. C, 6. B, 7. A, 8. B, 9. C, 10. C
***********************************************************************









------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------
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Cell biology - Cell division


1. Polyribosomes are aggregates of
a)Ribosomes and RNA    b)Only RNA   c)Peroxisomes   d)Several ribosomes held together by string of mRNA
2. Cytoplasm of one cell is continuous with that of the adjacent cell through
q)Plasmodesmata    b)Pits   c)Endoplasmic reticulum   d)Middle lamella
3. Nucleolus takes part in synthesis of
a)rRNA    b)tRNA   c)mRNA   d)DNA
4. Site for protein synthesis is
a)Pyrenoid    b)Chloroplast   c)Ribosome   d)Mitochondrion
5. Nucleus was discovered by
a)Purkinje    b)Nageli   c)Brown   d)Homeistet
6. Cell organelle covered by a single unit membrane is
a)Glyoxysome    b)Lysosome   c)Peroxisome   d)All the above
7. Enzymes associated with converting fats to carbohydrates are located in
a)Liposomes    b)Golgi bodies   c)Glyoxysomes   d)Microsomes
8. Secretory function of cell is carried out by
a)Peroxisomes    b)Golgi apparatus   c)Lysosomes   d)Sphaerosomes
9. Chromosomes present in prolonged prophase in the salivary glands of Drosophilla are
a)Polytene    b)Lampbrush   c)B-chromosomes   d)Supernumerary chromosomes
10. Best stage to observe shape, size and number of chromosomes is
a)Interphase    b)Metaphase   c)Prophase   d)Telophase
Answer
1d, 2a, 3a, 4c, 5c, 6d, 7c, 8b,9a, 10b



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Molecular biology Exam Questions And Answers

1.DNA sequence is TAG. What shall be the sequence in anticodon of tRNA
(a) UAG
(b) ATC
(c) ATG
(d) UAC		Answer: (a)
2.DNA sequence of ATTCGATG is transcribed as
(a) AUUCGAUG
(b) UAAGCUAC
(c) CAUCGAAU
(d) GUAGCUUA		Answer: (b)
3.DNA strand with nitrogen base sequence ATTGCC will have sequence in mRNA
(a) UAACGC
(b) ATCGCC
(c) ATTGCA
(d) AGGACC		Answer: (a)
4.Double chained DNA strand is made radioactive in both its chains. It is allowed to replicate twice in non-radioactive medium. The result would be
(a) All strands have radioactivity
(b) Half the strands have radioactivity
(c) Three strands have radioactivity
(d) Radioactivity is absent in all strands		Answer: (b)
5.Double helical structure of DNA was proposed by
(a) Kornberg
(b) Nirenberg
(c) Watson and Crick
(d) Wilkins and Franklin		Answer: (c)
6.Functional unit of gene that specifies synthesis of one polypeptide is
(a) Codon
(b) Cistron
(c) Recon
(d) Muton		Answer: (b)
7.Gene is segment of
(a) RNA
(b) DNA
(c) RNA or DNA
(d) Both DNA and RNA		Answer: (b)
8.Genetically engineered bacteria are being used in commercial production of
(a) Melatonin
(b) Testoteron
(c) Human insuline
(d) Thyroxine		Answer: (c)
9.Haploid plant cultures are got from
(a) Leaves
(b) Root tip
(c) Pollen grain
(d) Buds		Answer: (c)
10.Hydrogen bonds present between cytosine and guanosine are
(a) 2
(b) 3
(c) 1
(d) 4		Answer: (b)


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Molecular Biology Practice Questions Multiple Choice

1.RNA that picks up specific amino acid from amino acid pool of cytoplasm to carry it to ribosome during protein synthesis is
(a) tRNA
(b) mRNA
(c) rRNA
(d) gRNA		Answer: (a)
2.Semiconservative DNA / Chromosome replication using 14N was demonstrated by
(a) Messelson
(b) Tylor
(c) Messelson and stahl
(d) Hershey and Chase		Answer: (c)
3.Similarity between DNA and RNA is that both have
(a) Similar sugars
(b) Similar mode of replication
(c) Similar pyrimidines
(d) Polymers of nucleotides		Answer: (d)
14.Structure of DNA was given by
(a) Kornberg
(b) Nirenberg
(c) Watson and Crick
(d) Holley and Nirenberg		Answer: (c)
15.Successive nucleotides are covalently linked through
(a) Glycosidic bonds
(b) Phosphodiester bonds
(c) Hydrogen bonds
(d) Nitrogen bonds		Answer: (b)
16.Termination of polypeptide chain is brought about by
(a) UUG, UAG and UCG
(b) UAA, UAG and UGA
(c) UUG, UGC and UCA
(d) UCG, GCG and ACC		Answer: (b)
7.The basic uniot of a nucleic acid is
(a) Pentose sugar
(b) Nucleoid
(c) Nucleoside
(d) Nucleotide		Answer: (d)
8.The codon for anticodon 3’ UUUA – 5’ is
(a) 5’ AAAU- 3’
(b) 5’ UUUA- 3’
(c) 3’ UAAD- 5’
(d) 3’ AUUU- 5’		Answer: (a)
9.The common feature amongst nucleus, chloroplast and mitochondria is
(a) Lamellae
(b) DNA
(c) Cristae
(d) All the above		Answer: (b)
10.The enzyme taking part in joining two ends of DNA is
(a) Ligase
(b) Polymerase
(c) Gyrase
(d) Helicase		Answer: (a)


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QUIZ MOLECULAR BIOLOGY

1.Pomato is somatic
(a) Poppy and Potato
(b) Potato and tomato
(c) Poppy and tamarind
(d) Poppy and Tomato		Answer: (b)
2.Preserving germplasm in frozen state is
(a) Cryopreservation
(b) Cold storage
(c) In situ preservation
(d) Vernalisation		Answer: (a)
3.Protein helping in opening of  DNA double helix in front of replication fork is
(a) DNA gyrase
(b) DNA Polymerase I
(c) DNA ligase
(d) DNA topoisomerase		Answer: (a)
4.Pyrimidine base present in RNA in place of thymine of DNA is
(a) Uracil
(b) Adenine
(c) Cytosine
(d) Guanine		Answer: (a)
5.Restriction endonuclease is employed for cutting
(a) A single stranded DNA
(b) Double stranded DNA
(c) RNA fragment
(d) mRNA		Answer: (b)
6.Restriction endonucleases are
(a) Used in genetic engineering for uniting two DNA molecules
(b) Used for in vitro DNA synthesis
(c) Present in mammalian cells for degeneration of DNA of dead cells
(d) Synthesised by bacteria for their defence		Answer: (d)
7.Restriction enzymes are used in genetic engineering because they
(a) Can join DNA fragment
(b) Cut DNA at specific base sequence
(c) Cut DNA at variable sites
(d) Are proteolytic enzymes which degrade harmful proteins		Answer: (b)
8.Reverse transcriptase is
(a) RNA dependent RNA polymerase
(b) DNA dependent RNA polymerase
(c) DNA dependent DNA polymerase
(d) RNA dependent DNA polymerase		Answer: (d)
9.RNA contains
(a) Hexose
(b) Ribose
(c) Fructose
(d) Glucose		Answer: (b)
10.RNA does not possess
(a) Uracil
(b) Thymine
(c) Adenine
(d) Cytosine		Answer: (b)


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Molecular Biology – Multiple Choice

1.In a DNA molecule cytosine is 18%. Percentage of adenine would be
(a) 32%
(b) 64%
(c) 36%
(d) 18%		Answer: (a)
2.In AGCT of DNA hydrogen bonds and base pairings occur between
(a) A-U, C-G
(b) A-C, G-T
(c) A-G,C-T
(d) A-T,C-G		Answer: (d)
3.In callus culture, roots can be induced by the supply of
(a) Auxin and no cytokinin
(b) Higher concentration of auxin and lower concentration of cytokinin
(c) Higher concentration of cytokinin and lower concentration of auxin
(d) Both auxin and cytokinin in equal proportions.		Answer: (b)
4.In DNA, adenine pairs with
(a) Guanine
(b) Thymine
(c) Cytosine
(d) Uracil		Answer: (b)
5.In DNA, guanine lies opposite
(a) Uracil
(b) Cytosine
(c) Adenine
(d) thymine		Answer: (b)
6.In double helix of DNA, the two DNA strands are
(a) Coiled around a common axis
(b) coiled around each other
(c) coiled differently
(d) Colied over protein sheath		Answer: (a)
7.In RNA, thymine is replaced by
(a) Adenine
(b) Guanine
(c) Cytosine
(d) Uracil		Answer: (d)
8.In tissue / bacterial culture glassware and nutrients are sterilized through
(a) Water bath at 200° C
(b) Dry air oven at 200° C
(c) Dehumidifire
(d) Autoclave		Answer: (d)
9.In tissue culture, callus can be induced to form shoot or root by altering the ratio of
(a) Auxin to cytokinin
(b) Cytokinin to ethylene
(c)  Auxin to gibberellin
(d) Gibberellin to cytokinin		Answer: (a)
10.Initiation codon of protein synthesis (in eucaryotes) is
(a) GUA
(b) GCA
(c) CCA
(d) AUG		Answer: (d)


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