WorksheetsPPCHEM M9 Q3 FINALS
Total questions: 20
Worksheet time: 10mins
Which of the following statements most accurately describes the structural and functional relationship between an apoenzyme and its cofactors?
Apoenzyme is the inorganic ion, and cofactors are the protein parts that stabilize it.
Apoenzyme alone is catalytically active; cofactors modulate substrate binding.
Apoenzyme is the protein portion of an enzyme requiring cofactors (organic or inorganic) to become catalytically active.
Cofactors are exclusively vitamins that form the enzyme’s peptide backbone.
Considering enzymatic activity, how does temperature affect enzyme structure and function above the optimal range of 35-40 °C?
Increased temperature causes reversible conformational changes without activity loss.
Above 65 °C with moisture, enzymes undergo irreversible denaturation, resulting in complete loss of catalytic activity.
Enzymes become more efficient at catalysis above 65 °C due to increased kinetic energy.
Enzymatic activity plateaus and remains stable at extreme temperatures due to compensatory ionic bonding.
Which of the following is NOT a principal classification of enzymes based on their action as per the International Union of Biochemistry system?
Ligases – catalyze the joining of two molecules coupled with ATP cleavage.
Hydrolases – catalyze group transfer reactions other than hydrogen atoms.
Isomerases – catalyze geometric and optical isomer interconversions.
Lyases – catalyze removal of groups to form double bonds without hydrolysis.
Which enzyme initiates polysaccharide digestion in humans, and how does its presence differ across animal species?
Pancreatic amylase; present exclusively in carnivorous animals.
Ptyalin (Salivary amylase); present in humans but absent in species like dogs and horses.
Maltase; universally present in all animals.
Invertase; found only in herbivores.
In enzymology, why is the enzyme papain uniquely suited for obstetric surgical applications such as episiotomy?
It selectively coagulates milk proteins to reduce bleeding.
It functions exclusively in acidic gastric environments to aid protein digestion.
It is a proteolytic enzyme mixture capable of soft tissue debridement and gentle protein degradation.
It inhibits trypsin to decrease enzymatic activity during surgery.
Enzymes like urease are widely used in laboratories to catalyze urea degradation. From which natural source is urease primarily extracted?
Oily seeds rich in lipase
Soybeans
Gastric juices of mammals
Pancreatic juice from hogs
What sets apart derived proteins (secondary derived) like peptones from primary proteins?
They retain complete tertiary structure with no hydrolysis.
They represent extensively hydrolyzed protein fragments with molecular weights lower than proteoses.
They are formed only by heat denaturation without any enzymatic action.
They contain inorganic cofactors such as metals exclusively.
How does the enzyme thrombin contribute to hemostasis?
By hydrolyzing triglycerides into fatty acids.
By converting fibrinogen into insoluble fibrin to form blood clots.
By reducing oxidized cofactors in biochemical pathways.
By catalyzing urea degradation to ammonia.
Tissue plasminogen activator (T-PA) is clinically significant. Which cell line is used for its recombinant production?
Escherichia coli
Chinese Hamster Ovary cells
Bacillus subtilis
Streptococci group C bacteria
Which conjugated protein class contains a colored prosthetic group and includes hemoglobin as an example?
Glycoproteins
Metalloproteins
Chromoproteins
Phosphoproteins
Which of the following enzymes catalyzes the hydrolysis of glycosidic bonds in cyanogenic glycosides such as amygdalin?
Emulsin
Myrosin
Zymase
Maltase
Select the lipolytic enzyme that is widely distributed in both animal pancreatic juice and oily vegetable seeds.
Steapsin
Lipase
Urease
Pectase
Which of the following enzymes is specifically used for wound debridement by breaking down necrotic tissue?
Sutilains
Lactase
Invertase
Streptokinase
L-Asparaginase is used as an antitumor agent. What is its mechanism of action?
It inhibits DNA replication by binding to polymerases.
It selectively degrades L-Asparagine, starving tumor cells that require it.
It enhances immune cell activation against cancer cells.
Acts as an antioxidant scavenging free radicals.
Which of the following amino acids belong to the neutral aromatic group?
Tyrosine and Phenylalanine
Lysine and Arginine
Aspartic acid and Glutamic acid
Cysteine and Methionine
In the classification of proteins, which type is characterized by combination with non-protein moieties like nucleic acids or carbohydrates?
Simple Proteins
Derived Proteins
Conjugated Proteins
Primary Proteins
Which enzyme is preferentially active in alkaline medium around pH 8 and is a proteolytic enzyme more active than pepsin?
Pepsin
Erepsin
Trypsin
Rennin
The enzyme emulsin, derived from almonds, catalyzes which of the following reactions?
Hydrolyzes starch to maltose
Hydrolyzes β-glucosides producing glucose, benzaldehyde and hydrogen cyanide
Converts sucrose to glucose and fructose
Converts fat to glycerin and fatty acids
How is pancreatin used therapeutically?
As an anticoagulant
As a digestive aid containing amylase, lipase and protease
For local hemostasis
To dissolve fibrin clots in blood vessels
Glycoproteins, an important subclass of conjugated proteins, contain which characteristic group?
Metal ions
Lipids
Carbohydrate groups
Nucleic acids
