A Level Biology Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Image Description

Question: 1 / 715

What are carbohydrates primarily composed of?

Carbon, hydrogen, and nitrogen

Carbon, hydrogen, and oxygen

Carbohydrates are primarily composed of carbon, hydrogen, and oxygen. The general formula for carbohydrates can often be represented as \( C_n(H_2O)_n \), highlighting the presence of these three elements in a fixed ratio. The carbon forms the backbone of the carbohydrate structure, while the hydrogen and oxygen typically appear in proportions that reflect water molecules.

In terms of structure, carbohydrates can exist as simple sugars (monosaccharides like glucose) or more complex forms (disaccharides like sucrose, and polysaccharides like starch and cellulose). Regardless of their complexity, the fundamental composition remains consistent with the inclusion of these three elements.

Understanding this composition is crucial in biochemistry, as carbs play vital roles in energy storage, providing structural integrity in cell walls, and serving as important signaling molecules.

Get further explanation with Examzify DeepDiveBeta

Oxygen, nitrogen, and sulfur

Hydrogen, carbon, and phosphorus

Next Question

Report this question

Download A Level Biology Practice Exam PDF Study Guide
Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy