1st Year Biology Chapter 5 TestEnzymes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. Enzymes are also known as:

   1. Coenzymes

   2. Substrates

   3. Biocatalysts

   4. Metabolites

2. What is denaturation of an enzyme?

   1. A reversible change in enzyme shape

   2. Permanent loss of enzyme activity due to temperature or pH

   3. Reaction with substrate

   4. Temporary inhibition of active site

3. Why do different types of cells have different sets of enzymes?

   1. Because they all perform the same chemical reactions

   2. Because red blood cells and nerve cells have different chemical reactions

   3. Because enzymes are not important in cells

   4. Because all cells have identical functions

4. Which enzyme breaks starch into maltose?

   1. Sucrase

   2. Amylase

   3. Lactase

   4. Cellulase

5. Who proposed the Lock-and-Key model of enzyme action?

   1. Daniel Koshland

   2. Emil Fischer

   3. Louis Pasteur

   4. James Watson

6. What serves as substrate for the enzyme of the next step in metabolic pathways?

   1. The original substrate only

   2. The products from the previous enzyme's catalysis

   3. The enzyme itself

   4. Cofactors only

7. What is the effect of increasing enzyme concentration when substrate is unlimited?

   1. Reaction rate decreases

   2. Enzyme gets denatured

   3. More active sites become available and reaction rate increases

   4. Substrate concentration increases

8. What is true about irreversible inhibitors?

   1. They can be removed by dilution

   2. They make covalent bonds and cannot be removed

   3. They temporarily slow down reactions

   4. They bind only to coenzymes

9. What is the main importance of feedback inhibition?

   1. It promotes enzyme overproduction

   2. It initiates new metabolic pathways

   3. It helps cells regulate how much of an enzyme's end product is produced

   4. It allows all enzymes to bind permanently to substrates

10. What is the difference between a coenzyme and a prosthetic group?

    1. Coenzymes are metal ions; prosthetic groups are vitamins

    2. Coenzymes are loosely attached; prosthetic groups are tightly bound

    3. Coenzymes are proteins; prosthetic groups are non-proteins

    4. Coenzymes cannot transport electrons