An Apology

I apologize for no posting here.I am busy in my engineering universities tests so, as soon as i get free I will update the blog.

NUST Merit 2013

X-Ray Prodcution

Over a century ago in 1895, Roentgen discovered the first example of ionizing radiation, x-rays. The key to Roentgens discovery was a device called a Crooke’s tube, which was a glass envelope under high vacuum, with a wire element at one end forming the cathode, and a heavy copper target at the other end forming the anode. When a high voltage was applied to the electrodes, electrons formed at the cathode would be pulled towards the anode and strike the copper with very high energy. Roentgen discovered that very penetrating radiations were produced from the anode, which he called x-rays.
X-ray production whenever electrons of high energy strike a heavy metal target, like tungsten or copper. When electrons hit this material, some of the electrons will approach the nucleus of the metal atoms where they are deflected because of there opposite charges (electrons are negative and the nucleus is positive, so the electrons are attracted to the nucleus). This deflection causes the energy of the electron to decrease, and this decrease in energy then results in forming an x-ray.
Medical x-ray machines in hospitals use the same principle as the Crooke’s Tube to produce x-rays. The most common x-ray machines use tungsten as there cathode, and have very precise electronics so the amount and energy of the x-ray produced is optimum for making images of bones and tissues in the body.


Video Link :  http://www.dailymotion.com/video/x1axtdr_x-ray-production_school

Calvin Cycle

The Calvin cycle is a metabolic pathway found in the stroma of the chloroplast in which carbon enters in the form of CO2 and leaves in the form of sugar.



The Calvin Cycle

The cycle spends ATP as an energy source and consumes NADPH2 as reducing power for adding high energy electrons to make the sugar. There are three phases of the cycle. In phase 1 (Carbon Fixation), CO2 is incorporated into a five-carbon sugar named ribulose bisphosphate (RuBP). The enzyme which catalyzes this first step is RuBP carboxylase or rubisco. It is the most abundant protein in chloroplasts and probably the most abundant protein on Earth. The product of the reaction is a six-carbon intermediate which immediately splits in half to form two molecules of 3-phosphoglycerate. In phase 2 ( Reduction), ATP and NADPH2from the light reactions are used to convert 3-phosphoglycerate to glyceraldehyde 3-phosphate, the three-carbon carbohydrate precursor to glucose and other sugars. In phase 3 (Regeneration), more ATP is used to convert some of the of the pool of glyceraldehyde 3-phosphate back to RuBP, the acceptor for CO2, thereby completing the cycle. For every three molecules of CO2 that enter the cycle, the net output is one molecule of glyceraldehyde 3-phosphate (G3P). For each G3P synthesized, the cycle spends nine molecules of ATP and six molecules of NADPH2. The light reactions sustain the Calvin cycle by regenerating the ATP and NADPH2.

Video Link :  http://www.dailymotion.com/video/x1avq9n_calvin-cycle_school

Autonomic Nervous System

The autonomic nervous system (ANS or visceral nervous system or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system, functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiratory rate,salivation, perspiration, pupillary dilation, micturition (urination), and sexual arousal. Most autonomous functions are involuntary but they can often work in conjunction with the somatic nervous system which gives voluntary control. Everyday examples includebreathing, swallowing, and sexual arousal, and in some cases functions such as heart rate.


Within the brain, the ANS is located in the medulla oblongata in the lower brainstem. The medulla's major ANS functions include respiration (the respiratory control center, or "rcc"), cardiac regulation (the cardiac control center, or "ccc"), vasomotor activity (the vasomotor center or "vmc"), and certain reflex actions (such as coughing, sneezing, vomiting and swallowing). These then subdivide into other areas and are also linked to ANS subsystems and nervous systems external to the brain. The hypothalamus, just above the brain stem, acts as an integrator for autonomic functions, receiving ANS regulatory input from the limbic system to do so.

The ANS is classically divided into two subsystems: the parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS), which operate independently in some functions and interact co-operatively in others. In many cases, the two have "opposite" actions where one activates a physiological response and the other inhibits it. An older simplification of the sympathetic and parasympathetic nervous systems as "excitory" and "inhibitory" was overturned due to the many exceptions found. A more modern characterization is that the sympathetic nervous system is a "quick response mobilizing system" and the parasympathetic is a "more slowly activated dampening system", but even this has exceptions, such as in sexual arousal andorgasm, wherein both play a role. The enteric nervous system is also sometimes considered part of the autonomic nervous system, and sometimes considered an independent system[by whom?].


In general, ANS functions can be divided into sensory (afferent) and motor (efferent) subsystems. Within both, there are inhibitory and excitatory synapsesbetween neurons. Relatively recently, a third subsystem of neurons that have been named 'non-adrenergic and non-cholinergic' neurons (because they usenitric oxide as a neurotransmitter) have been described and found to be integral in autonomic function, in particular in the gut and the lungs.

Video Link: http://www.dailymotion.com/video/x1avpa0_autonomic-nervous-system_school

Joints in Human Skeleton

Types of Joints

A need for strength makes the bones rigid, but if the skeleton consisted of only one solid bone, movement would be impossible. Nature has solved this problem by dividing the skeleton into many bones and creating joints where the bones intersect. Joints, also known as articulations, are strong connections that join the bones, teeth, and cartilage of the body to one another. Each joint is specialized in its shape and structural components to control the range of motion between the parts that it connects

Joints may be classified functionally based upon how much movement they allow.

• A joint that permits no movement is known as a synarthrosis. The sutures of the skull and the gomphoses that connect the teeth to the skull are examples of synarthroses.
• An amphiarthrosis allows a slight amount of movement at the joint. Examples of amphiarthroses include the intervertebral disks of the spine and the pubic symphysis of the hips.
• The third functional class of joints is the freely movable diarthrosis joints. Diarthroses have the highest range of motion of any joint and include the elbow, knee, shoulder, and wrist.

Joints may also be classified structurally based upon what kind of material is present in the joint.

• Fibrous joints are made of tough collagen fibers and include the sutures of the skull and the syndesmosis joint that holds the ulna and radius of the forearm together.
• Cartilaginous joints are made of a band of cartilage that binds bones together. Some examples of cartilaginous joints include joints between the ribs and costal cartilage, and the intervertebral disks of the spine.
• The most common type of joint, the synovial joint, features a fluid-filled space between smooth cartilage pads at the end of articulating bones. Surrounding the joint is a capsule of tough dense irregular connective tissue lined with synovial membrane. The outer layer of capsule may extend into thick, strong bands called ligaments that reinforce the joint and prevent undesired movements and dislocations. Synovial membrane lining the capsule produces the oily synovial fluid that lubricates the joint and reduces friction and wear.

There are many different classes of synovial joints in the body, including gliding, hinge, saddle, and ball and socket joints.

• Gliding joints, such as the ones between the carpals of the wrist, are found where bones meet as flat surfaces and allow for the bones to glide past one another in any direction.
• Hinge joints, such as the elbow and knee, limit movement in only one direction so that the angle between bones can increase or decrease at the joint. The limited motion at hinge joints provides for more strength and reinforcement from the bones, muscles, and ligaments that make up the joint.
• Saddle joints, such as the one between the first metacarpal and trapezium bone, permit 360 degree motion by allowing the bones to pivot along two axes.
• The shoulder and hip joints form the only ball and socket joints in the body. These joints have the freest range of motion of any joint in the body – they are the only joints that can move in a full circle and rotate around their axis. However, the drawback to the ball and socket joint is that its free range of motion makes it more susceptible to dislocation than less mobile joints.
  
  Video Link:  http://www.dailymotion.com/video/x1avoob_human-skeleton-types-of-joints_school

DNA Transcription

Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as acomplementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary,antiparallel RNA strand called a primary transcript. As opposed to DNA replication, transcription results in an RNA complement that includes the nucleotide uracil (U) in all instances where thymine (T) would have occurred in a DNA complement. Also unlike DNA replication where DNA is synthesised, transcription does not involve an RNA primer to initiate RNA synthesis.

Transcription can be reduced to the following steps, each moving like a wave along the DNA.

1. One or more sigma factors initiate transcription of a gene by enabling binding of RNA polymerase to promoter DNA.
2. RNA polymerase moves a transcription bubble, like the slider of azipper, which splits the double helix DNA molecule into two strands of unpaired DNA nucleotides, by breaking the hydrogen bonds between complementary DNA nucleotides.
3. RNA polymerase adds matching RNA nucleotides that are paired with complementary DNA nucleotides of one DNA strand.
4. RNA sugar-phosphate backbone forms with assistance from RNA polymerase to form an RNA strand.
5. Hydrogen bonds of the untwisted RNA + DNA helix break, freeing the newly synthesized RNA strand.
6. If the cell has a nucleus, the RNA may be further processed (with the addition of a 3'UTR poly-A tail and a 5'UTR cap) and exits to the cytoplasm through the nuclear pore complex.

The stretch of DNA transcribed into an RNA molecule is called a transcription unit and encodes at least one gene. If the gene transcribed encodes aprotein, the result of transcription is messenger RNA (mRNA), which will then be used to create that protein via the process of translation. Alternatively, the transcribed gene may encode for either non-coding RNA genes (such as microRNA, lincRNA, etc.) or ribosomal RNA (rRNA) or transfer RNA (tRNA), other components of the protein-assembly process, or other ribozymes.^[1]

A DNA transcription unit encoding for a protein contains not only the sequence that will eventually be directly translated into the protein (the coding sequence) but also regulatory sequences that direct and regulate the synthesis of that protein. The regulatory sequence before (i.e., upstream from) the coding sequence is called the five prime untranslated region (5'UTR), and the sequence following (downstream from) the coding sequence is called thethree prime untranslated region (3'UTR).^[1]

Transcription has some proofreading mechanisms, but they are fewer and less effective than the controls for copying DNA; therefore, transcription has a lower copying fidelity than DNA replication.^[2]

As in DNA replication, DNA is read from 3' end → 5' end during transcription. Meanwhile, the complementary RNA is created from the 5' end → 3' end direction. This means its 5' end is created first in base pairing. Although DNA is arranged as two antiparallel strands in a double helix, only one of the two DNA strands, called the template strand, is used for transcription. This is because RNA is only single-stranded, as opposed to double-stranded DNA. The other DNA strand (the non-template strand) is called the coding strand, because its sequence is the same as the newly created RNA transcript (except for the substitution of uracil for thymine). The use of only the 3' end → 5' end strand eliminates the need for the Okazaki fragments seen in DNA replication.^[1]

In virology, the term may also be used when referring to mRNA synthesis from a RNA molecule (i.e. RNA replication). For instance, the genome of an negative-sense single-stranded RNA (ssRNA -) virus may serve as a template to transcribe a positive-sense single-stranded RNA (ssRNA +) molecule, since the positive-sense strand contains the information needed to translate the viral proteins for viral replication afterwards. This process is catalysed by a viral RNA replicase.

Bremsstrahlung

Bremsstrahlung, from bremsen "to brake" and Strahlung "radiation", i.e. "braking radiation" or "deceleration radiation") is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. The moving particle loses kinetic energy, which is converted into a photon because energy is conserved. The term is also used to refer to the process of producing the radiation. Bremsstrahlung has a continuous spectrum, which becomes more intense and whose peak intensity shifts toward higher frequencies as the change of the energy of the accelerated particles increases.

Strictly speaking, braking radiation is any radiation due to the acceleration of a charged particle, which includes synchrotron radiation, cyclotron radiation, and the emission of electrons and positrons during beta decay. However, the term is frequently used in the more narrow sense of radiation from electrons (from whatever source) slowing in matter.

Bremsstrahlung emitted from plasma is sometimes referred to as free-free radiation. This refers to the fact that the radiation in this case is created by charged particles that are free both before and after the deflection (acceleration) that caused the emission.

Polymerase Chain Reaction

The polymerase chain reaction (PCR) is a biochemical technology in molecular biology toamplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence.

Test Schedule Part-A Jan-Feb

Test Location : https://www.facebook.com/MCATians2014

Biology Random MCQs

Blood cells with smallest size r
Erythrocytes
Leucocytes
Thrombocytes
Granulocytes

Pericycle in plants lies
External to cortex
External to endodermis
Internal to endodermis
Central most

Most bacteria exist in forms
1
2
3
5

A co factor that is permanent part of enzyme
Activator
Co enzyme
Prosthetic group
All

Micromolecules found in livng organism are
Always organic
Store house
Building blocks
Polymers

Accrding to schldein n schwan a cell cnsists plasma membrane,cell wall n cytoplasm n nucleus all is true except in
Paramecium
Allium cepa
Planaria
Nostoc

Rate of diffusion is high in a tissue having
Loose arrangemnt
Compct arrngmnt
No intercellulr spaces
Compact having cuticle

Longest parr of foregut in cockroacg is
Buccal cavity
Oesophagus
Crop
Gizzard

Plasmodium of myxomycota is multinucleate structure with each nucleus
Haploid
Diploid
Triploid
Polyploid

These are extremely complex and includes biological rhythms
Kinesis
Taxes
Instincts
Learning

Down syndrome is ab example of
Monoploidy
Aneuploidy
Polyploidy
Diploidy

Is is a type of plant movemnt that is spontaneous and selfcontrolled?
Epinasty
Chemo tropism
Haptonasty
Nyctinasty

Active trsnsport is selective and is dependant upon
A photosynthesis
B respiration
C transportation
D permeability

The amount of CO2 carried by pulmonary artery is
A 50ml/100ml blood
B 54ml/100ml blood
C 4ml/100ml blood
D 20ml/100ml blood

Rubisco oxygenase is involved in fixation of
A o2 in calvin cycl
B o2 in photorespration

Spores and sporangia are most common characters of
A zygomycetes
B Ascomycetes
C Basidiomycetes
D duetromycetes

The amount of CO2 carried by pulmonary artery is
A 50ml/100ml blood
B 54ml/100ml blood
C 4ml/100ml blood
D 20ml/100ml blood

IS RESPONSIBLE FOR THE ACTIVATION OF CATALIC SITE?
LOW TEMP
EI COMPLEX
ES COMPLEX
SUBSTRATE

Prophage consists of
A DNA n protein
B only protein
C only DNA of host
D only DNA of phage

Phylogeny describes a species
A morphological similarities
B evolutionary history
C Developmental history
D geographical distribution

Component responsible for determination of viral shape
A kind of nucleic acid
B protein sub units
C kind of hosts
D viral envelop

FOR IONS AND CHARGED PARTICLES ,LIPID BILAYER IS
FREELY PERMEABLE
SEMI PERMEABLE
IMPERMEABLE
SELECTIVELY PERMEABLE

CENTRIOLES EXIST IN
CENTROSOME
CENTROMERE
NUCLEOSOME NUCLEOID

THE CHEMICAL SUBSTNC MOST ABUNDNT IN MIDDL LAMELLA:
SUBRIN
LIGNIN
CELLULOSE
PECTIN

THE CELL WALL FORMATION IN PLANTS ID DETERMINED BY:
GOLGI BODIES
ER
MICROTUBULES
NUCLEOLUS

CELL MEMBRANE OF EKARYOTES CONTAIN:
PHOSPHOLIPIDS
CHOLESTRL
PROTEINS
ALL

the anaerobic respirations occur in:
A CYTOPLASM
B MITOCHONDRIA
C CHLOROPLAST
D NUCLEUS

The nuclear material is directly submerges in cytoplams in
A bacteria
B green algae
C amoeba
D animal cell

Storage of calcium ions in muscls is function of:
A rough ER
B smooth ER
C golgi bodies
D cytoplasm

Wood contains
A proteins
B cellulose n proteins
C cellulose

The length of mRna depends upon:
A size of gene
B size of polypeptide
C size of tRna
D both a n b

Glycerol can b alternatively called as:
A.trihydroxyl alcohol
B.triacylglycerok
C.fatty acid
D.phospholipid

Long term regulation by harmones are brought in:
A.animals
B.plants
C.both a and b?

Biology deals wit the study of
A. Living thng only?
B.Organisms n related envirnmnt?
plx anyone cn answer?

Admission Schedule for HSSC Annual Examination,2014

Chemistry Ist Year Unit # 2

Distribution law is employed in which of the following
(A) paper chromatography
(B) sublimation
(C) crystillization
(D) solvent extraction

2.when hot saturated solution is cooled rapidly we get
(A) medium sized crystalls
(B) large sized crystals
(C) premature crystillization
(D) no crystallization

3.when I2 is presnent in aqueous layer in form of I3^-1 goes to CCl4 layer then the change in colour is from
(A) purple to brown
(B) purple to green
(C) green to brown
(D) brown to purple

4. The crystallization of a solid substance is done from hot saturated solution. The solution is
(A) evaporated rapidly
(B) cooled slowly to get good crystalls
(C) cooled rapidly to get excellent crystals
(D) mixed with another miscible solvent

5) A sintered glass crucible can be used to :
(A) purify a solid substance
(B) crystallize the solid substance
(C) seperate two miscible liquids
(D) avoid premature crystallization of solute

6. When a solute distributes b/w a stationary phase and a mobile phase the process is called
(A) sublimation
(B) crystallization
(C) solvent extraction
(D) chromatography

7. The iodine present in water can be seperated by which of the following techniques:
(A) sublimation
(B) chromatography
(C) filtration
(D) solvent extraction

8. The process of solvent extraction is an equilibrium process and it obeys
(A) the realtive amounts of solvent and solute
(B) law of mass action
(C) distribution law
(D) all above

9. I2 present in water can be extracted by:
(A) Etanol
(B) acetic acid
(C) chloroform
(D) ccl4

10. Nacl and sand can be seperated by:
(A) formation of solution and filtration
(B) formation of solution and evaporation without filtration
(C) sublimation
(D) chromatograph

11. one of the following substance is used as drying agent in dessicator is
(A) diethyl ether
(B) bleaching powder
(C) silica gel
(D) phosphoric acid

12. which of the following substances used as decoluring agent
(A) animal charcoal
(B) Conc H2so4
(C) Cacl2
(D) silica gel

13 chemical characterization of the substance is
(A) physical chemistry
(B) applied chemistry
(C) analytical chemistry
(D) biochemistry

14. one of the following agent is not used as drying reagent in a dessicator
(A) conc H2SO4
(B) P2O5
(C) silica gel
(D) 50% KOH

15. In order to dry the crystals safely , we should :
(A) place them in an oven
(B) evaporate the solvent at room temperature
(C) warm the substances
(D) press the precipitate between folds of filter paper

16. When repeated extraction are performed by using small quantities of the solvent then this process is more
(A) efficient
(B) rapid
(C) accurate
(D) slow

17. which of the following substances is a sublime material
(A) potash alum
(B) Nacl
(C) Acetic acid
(D) benzoic acid

18. One of the following substance doesnot undergo sublimation
(A) KMNO4
(B) Naphthalene
(C) NH4Cl
(D) Iodine

19. In.paper chromatography the point at which solvent rises to maximum extent is
(A) event
(B) chromayogram
(C) solvent front
(D) baseline

20. The rate at which solute moves in paper chromatography depends upon
(A) distribution coefficeint
(B) distribution law
(C) boiling point if solvent
(D) low partial pressures

Biology Part 1 Unit # 3 MCQs

1-Most important group of proteins which r biologically active are
A-harmoglobin
B-enzymes
C-inhibitors
D-both b and c

2- where does the catalytic activity takes place in enzyme
A-binding site
B-catalytic site
C-active site
D-globular site

3-in there action enzymes r very
A-general
B-precise
C-specific
D-exact

4-the non protein part essential for its proper funtioning
A-activator
B-co-enzyme
C-co-factor
D-prosthetic group

5-what acts as a bridge b/w enzyme &. its sybstrate
A-active site
B-globular shape of enzyme
C-co-factor
D-both a & c

6-the detachable inorganic part of enzyme
A-prosthetic group
B-co-enzyme
C-activitor
D-co-factor

7-enzymes important in photosynthesis n cellular respiration are found in
A-mithochondria & chromoplast
B-cell wall & cell membrane
C-chloroplast & mithochondria
D-E.R & golgi bodies

8-which statement about enzyme is not true
A-they consists of protein with or without a non-protein part
B-they changed the rate of catalytic reaction
c-they r sensitive to heat
D-they increases the activation energy

9-the active site of an enzyme
A-never changes
B-forms no chemical bonds with substrate
C-determines,by its structure the specificity of enzyme
D-looks like a lump projecting from the surface of enzyme

10-the rate of an enzyme catalysed reaction
A-is constant under all conditions
B-decreases as substrate concentration increases
C-cannot be measured
D-can be reduced by inhibitors

Q:11: The enzyme minus its coenzyme is referred to as the

(A) Iso-enzyme
(B) Metalloenzyme
(C) Apoenzyme
(D) All of these

Q:12: 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

Q:13: A catalyst is a chemical involved in, but not ____________ by, a chemical reaction.

(A) Supported
(B) Changed
(C) Controlled
(D) All of these

Q:14: 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

Q:15: Non-protein components of enzymes are known as

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

Q:16: 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

Q:17: 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

Q:18: 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

Q:19: Enzymes function as

(A) Organic catalysts
(B) Inorganic catalysts
(C) Inhibitors
(D) All of these

Q:20: A catalyst is a chemical involved in, but not ____________ by, a chemical reaction.

(A) Supported
(B) Changed
(C) Controlled
(D) All of these

Q:21: An activated enzyme made of polypeptide chain and a co-factor is

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

Q:22: Koshland in 1959 proposed

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

Q:23: Enzymes are largely _________________________ in their chemical nature.

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

Q:24: Who proposed “lock and key” model to study enzyme – substrate interaction?

(A) Koshland (1959)
(B) Wilhelm Kuhne (1878)
(C) Fischer (1890)
(D) None of these

Q:25: Many enzymes function by __________________ the activation energy of reactions.

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

Q:26: An uncatalysed reaction requires a

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

Q:27: 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

Q:28: 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

Q:29: 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

Q:30: _____________ 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 

Q:31: 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

Q:32: Proteinaceous part of holoenzyme is

(A) Prosthetic group 
(B) Apoenzyme
(C) Lecithin
(D) None of these

Q:33: The "lock and key hypothesis" attempts to explain the mechanism of

(A) vacuole formation
(B) pinocytosis
(C) sharing of electrons
(D) enzyme specificity

Q:34: 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

Q:35: The site where enzyme catalyzed reaction takes place is called?

(A) Active site
(B) Allosteric site
(C) Denatures site
(D) Dead Site

Q:36: What is a cofactor?

(A) Inorganic ions
(B) Organic molecules
(C) Both a and b
(D) None of the above

Q:37: 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

Q:38: Which of the following enzymes would digest a fat?

(A) sucrase
(B) protease
(C) Ligase
(D) lipase

Q:39: 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

Q:40: Which one is not attribute of enzyme

(A) Specific in nature
(B) Protein in chemistry
(C) Consumed in reaction
(D) Increases rate of reaction



 Correct ans=B,C,C,C,C,C,C,D,C,D,C,C,B,D,D,D,D,D,A,B,D,B,C,C,C,A,C,A,A,A,A,B,D,B,A,C,B,D,D,c