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BIO NMDCAT

1895 questions found

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📁 ACELLULAR LIFR 20 📁 AIDS and HIV Infection 50 📁 and nerve impulse Reflexes and reflex arc 0 📁 Arthritis 0 📁 axon 0 📁 BIOENERGETICS 0 📁 Biological Importance of Water 95 📁 BIOLOGICAL MOLECULES 126 📁 Biotechnology 0 📁 Biotechnology and Health Care 0 📁 Blood Vessels 0 📁 Brain 25 📁 Carbohydrates 100 📁 Cardiac cycle and phases of Heartbeat 0 📁 cell body 0 📁 cell membrane 70 📁 CELL STRUCTURE & FUNCTION 100 📁 Chromosomes 76 📁 Circulation 0 📁 Concept of Evolution 50 📁 Conjugated molecules 100 📁 COORDINATION & CONTROL NERVOUS & CHEMICAL COORDINATION 0 📁 Cytoplasmic Organelles 75 📁 Darwinism 50 📁 dendrites 0 📁 DIVERSITY AMONG ANTMALS (THE KTNGDOM ANIMALIA) 0 📁 ENZYMES 108 📁 EVOLUTION 0 📁 Factors that Affect the Rate of Enzyme Reactions 60 📁 Form and Function in Plants 0 📁 Gene linkage and crossing over 0 📁 Homeostasis (kidney specifically) 0 📁 Homeostasis Mainly Kidney Portion nmdcat etea 0 📁 Human Heart 0 📁 Human Reproductive system 0 📁 Human Reproductive system-Menstrual cycle 0 📁 Human skeleton 40 📁 INHERITANCE 0 📁 Inhibitors 40 📁 Joints 0 📁 Lamarckism 50 📁 Lipids 45 📁 lmmunity 0 📁 Lymphatic system 0 📁 Mendel's laws of Inheritance 0 📁 Menstrual cycle 0 📁 Mode of Enzyme Action 60 📁 Muscle contraction 0 📁 Muscles 70 📁 myelin sheath 0 📁 Neurons 41 📁 PROKARYOTES (KTNGDOM MONERA) 0 📁 Prokaryotic and Eukaryotic cell 0 📁 Proteins 95 📁 Receptors 40 📁 REPRODUCTION 0 📁 Respiration 15 📁 Respiratory system 0 📁 Ribonucleic acid (RNA) 100 📁 Sexually transmitted diseases 50 📁 Skeletal muscles 0 📁 Specific Defense Mechanism 0 📁 Structure of DNA 98 📁 SUPPORT & MOVEMENT 0 📁 Viruses 46 📁 X-linked Recessive inheritance 0

Practice Questions

Stereospecificity in enzyme action means the enzyme can

A. Change its own stereochemistry
B. Produce racemic products
C. Distinguish between optical isomers and act on only one ✓
D. Convert every substrate into its optical isomer
nmdcat.online BIO NMDCAT
Jul 11, 2026

In aldolase, formation of a Schiff base between lysine and the substrate is an example of

A. Cofactor mediated catalysis
B. Covalent catalysis ✓
C. Metal ion catalysis
D. General acid catalysis
nmdcat.online BIO NMDCAT
Jul 11, 2026

Vmax of an enzyme catalyzed reaction is reached when

A. The enzyme is denatured
B. Product concentration becomes zero
C. Further increase in substrate concentration fails to increase the reaction rate ✓
D. Km becomes zero
nmdcat.online BIO NMDCAT
Jul 11, 2026

Observation of a burst phase of rapid product formation followed by a slower steady state phase suggests

A. Random sequential binding
B. Rate limiting formation of a covalent enzyme substrate intermediate ✓
C. Rate limiting release of the first product
D. Slow activation of the free enzyme
nmdcat.online BIO NMDCAT
Jul 11, 2026

The active site of an enzyme is usually located in a deep cleft or pocket because it

A. Protects the enzyme from phosphorylation
B. Provides a large flat surface for adsorption
C. Sequesters the substrate from bulk solvent and creates a specialized environment ✓
D. Allows simultaneous binding to DNA and proteins
nmdcat.online BIO NMDCAT
Jul 11, 2026

A Lineweaver Burk plot supporting a ping pong mechanism shows

A. Lines intersecting on the x axis
B. Parallel lines at varying substrate concentrations
C. A single straight line ✓
D. A sigmoidal curve
nmdcat.online BIO NMDCAT
Jul 11, 2026

The active site of an enzyme is often described as a “microenvironment.” A key characteristic of this microenvironment is

A. A completely uniform charge distribution ✓
B. A significantly lowered dielectric constant that enhances electrostatic interactions
C. A pH always equal to 7.0
D. An unlimited supply of free water molecules
nmdcat.online BIO NMDCAT
Jul 11, 2026

A Bi substrate reaction following a Sequential Ordered mechanism is characterized by

A. Random substrate binding
B. Both substrates bind before any product is released, in a compulsory order ✓
C. Product leaves before all substrates bind
D. Reaction rate is independent of the second substrate
nmdcat.online BIO NMDCAT
Jul 11, 2026

An enzyme that catalyzes reactions without any non protein component relies solely on

A. Quaternary structure
B. Amino acid side chains arranged in the active site ✓
C. Alpha helices
D. Signal peptide
nmdcat.online BIO NMDCAT
Jul 11, 2026

The x intercept of a Lineweaver Burk plot equals

A. -1/Vmax
B. -1/Km ✓
C. Vmax/Km
D. Km/Vmax
nmdcat.online BIO NMDCAT
Jul 11, 2026

In lysozyme, Glu35 remains protonated because its microenvironment is

A. Highly hydrophilic
B. Hydrophobic and non polar ✓
C. Rich in lysine residues
D. Completely neutral
nmdcat.online BIO NMDCAT
Jul 11, 2026

A ping pong mechanism refers to a kinetic sequence where

A. Substrate inhibits product
B. One product is released before all substrates bind ✓
C. Cooperative binding occurs
D. Non competitive inhibition occurs
nmdcat.online BIO NMDCAT
Jul 11, 2026

Formation of a covalent enzyme substrate intermediate after the first product leaves is characteristic of

A. Sequential ordered mechanism
B. Sequential random mechanism
C. Ping pong double displacement mechanism ✓
D. Concerted acid base mechanism
nmdcat.online BIO NMDCAT
Jul 11, 2026

During the mechanism of chymotrypsin, the “pong” step involves

A. Release of the unaltered second substrate
B. Binding of a water molecule and its nucleophilic attack on the acyl enzyme intermediate ✓
C. Binding of an allosteric inhibitor
D. Auto degradation of the enzyme
nmdcat.online BIO NMDCAT
Jul 11, 2026

The catalytic efficiency of an enzyme is best described by the ratio

A. Kcat / Vmax
B. Km / Kcat
C. Kcat / Km ✓
D. Vmax / Kcat
nmdcat.online BIO NMDCAT
Jul 11, 2026

Catalysis by approximation is achieved by

A. Denaturing the substrate
B. Binding two substrates close together to increase their effective concentration ✓
C. Lowering the pH of the solution
D. Using a metal ion to generate hydroxyl radicals
nmdcat.online BIO NMDCAT
Jul 11, 2026

In triose phosphate isomerase, glutamate abstracts a proton from the substrate. It acts as a

A. General acid
B. Lewis acid
C. General base ✓
D. Metal ion cofactor
nmdcat.online BIO NMDCAT
Jul 11, 2026

Activation of the catalytic serine hydroxyl group in serine proteases is achieved by

A. Bulk water
B. Histidine acting as a general base ✓
C. Aspartate donating a proton
D. Formation of a disulfide bond
nmdcat.online BIO NMDCAT
Jul 11, 2026

Binding energy released during enzyme substrate interaction is primarily used to

A. Directly break substrate bonds
B. Increase activation energy
C. Lower activation energy by stabilizing the transition state ✓
D. Dissociate the enzyme cofactor complex
nmdcat.online BIO NMDCAT
Jul 11, 2026
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