All Free Biology MCQs with Answers

• A. Milk
• B. Eggs
• C. Beans
• D. Muscles

Explanation: Albumin, a water soluble protein, is the primary protein present in egg whites as ovalbumin. Serum albumin is present in the bloodstream. Milk has lactalbumin ( also known as whey protein ) which is a type of albumin as well but it isn't the primary protein present as it makes up a small percentage of total protein in milk. Muscles contain myoglobin and myofibrillar proteins like actin,myosin etc Salt soluble globulins amount up for 45 to 70% of the total protein in beans.

• A. It increases the enzyme activity
• B. Stops the reaction
• C. Decreases the enzyme activity
• D. Both b and c

Explanation: At optimum temperature enzymes have maximum activity, if the temperature increases further their activity decreases and at very high temperatures the enzymes will be denatured due to permanent deformation of the active sites and all activity will stop.

• A. Thousands
• B. Millions
• C. Hundreds
• D. Billions

Explanation: Enzymes are macromolecules with mass ranging between millions. This is the exact value from ptb ..it needs to be memorised.

• A. Co-factor
• B. Iso-zyme
• C. Active site
• D. Substrate

Explanation: Option D is correct as the "substrate" is attached to the enzyme at a specific site to be broken down.

• A. Biocatalyst
• B. Autocatalysis
• C. Heterocatalysis
• D. Homocatalysis

Explanation: Option C is correct as catalysts are generally foreign substances, but sometimes one of the products formed in a reaction can act as a catalyst. That is, it can increase the rate of the reaction. Such a catalyst is called an auto catalyst.This phenomenon is called autocatalysis. An example of "autocatalysis" is when oxalic acid is titrated with potassium permanganate in the presence of dilute sulphuric acid.

• A. Invertase
• B. Urease
• C. Glycolysis
• D. None

Explanation: Option A.Sucrose can be hydrolyzed to glucose and fructose by invertase enzyme.

• A. 9000
• B. Less than 10000
• C. 10000
• D. More than 10000

Explanation: d) More than 10000:This option is the most accurate statement. Proteins typically have molecular masses greater than 10000. Many common proteins have molecular masses in the range of tens to hundreds of kilodaltons (kDa), which is equivalent to thousands of daltons.

• A. Greek, Important.
• B. French, Prime Importance.
• C. Greek, Functional.
• D. Greek, Prime Importance.

Explanation: The name protein is derived from the Greek word "proteios", which means "primary" or "of prime importance". This is because proteins are essential biomolecules that serve a wide range of important functions in living organisms, including structural support, catalyzing chemical reactions, and transporting molecules across cell membranes. The name "protein" reflects the fundamental importance of these molecules in life processes.

• A. Nitrogen atoms.
• B. Amino acids.
• C. Glucose.
• D. Nitrogenous base.

Explanation: Protein is a polymer of amino acids. Amino acids are the monomers that make up proteins, and they are linked together by peptide bonds to form long chains called polypeptides. These polypeptide chains can then fold into specific three-dimensional structures, which determine the function of the protein. The sequence of amino acids in a protein is encoded by the genetic information in DNA, and any changes in this sequence can have significant effects on the protein's structure and function.

• A. Primary structure
• B. Secondary structure
• C. Tertiary structure
• D. Quaternary structure

Explanation: Tertiary structure is the compact structure of a protein molecule resulting from the three dimensional coiling of an already folded chain of amino acids. shape. This is caused by R-group interactions such as ionic and hydrogen bonds, disulphide bridges, and hydrophobic & hydrophilic interactions.