Class 9th · Biology · Chapter 7
Chapter 7: Enzymes
Chapter 7 of the Punjab Board Class 9th Biology textbook runs from page 109 to 118 and covers 5 topics. Open any of those pages in GenZ Books, tap a question, and the answer is worked from this chapter.
Open Chapter 7 of Biology in GenZ Books
The same Class 9th textbook, page for page. Tap any question and get the answer worked from that chapter — English and Urdu.
Topics in this chapter
- 7.1Metabolismp. 109
- 7.2Enzymesp. 110
- 7.3Mechanism of Enzyme Actionp. 112
- 7.4Factors that Affect the Activity of Enzymesp. 113
- 7.5Enzyme Inhibitionp. 115
A sample answer from GenZ Books
Define · page 118: 1. Describe the characteristics of enzymes.
Enzymes (انزائمز) are biological catalysts that speed up chemical reactions in living organisms by lowering the activation energy.
- Specificity – each enzyme works with only one or a few specific substrates (e.g., pepsin only digests proteins).
- Optimal conditions – they function best at a particular temperature and pH; outside this range their activity drops and they may denature.
- Non‑consumption – enzymes are not used up in the reaction; they can act repeatedly.
- Protein nature – they are made of amino acids and have a 3‑D structure that determines their function.
Example from everyday life in Pakistan: When you chew chapati or rice, the enzyme amylase (ایمیلیس) in your saliva starts breaking down the starch into simpler sugars, making the food easier to digest.
Remember: Enzymes are specific, non‑consumed catalysts that work best at an optimal temperature and pH.
AI-generated from the chapter text by GenZ Books. It can make mistakes — check it against your textbook and your teacher.