Problem 3 - Campbell Biology

Question

Which statement about unsaturated fats is true? (A) They are more common in animals than in plants. (B) They have double bonds in their fatty acid chains. (C) They generally solldify at room temperature. (D) They contain more hydrogen than do saturated fats having the same number of carbon atoms.

Step-by-Step Solution

Answer

Option (B) is true.

Step 1: Understand the Question

The task is to identify the true statement about unsaturated fats from the given options.

Step 2: Analyze Option (A)

Unsaturated fats are more commonly found in plants rather than animals.

Step 3: Analyze Option (B)

Unsaturated fats have double bonds in their fatty acid chains, which is why they are classified as 'unsaturated'.

Step 4: Analyze Option (C)

Unsaturated fats generally remain liquid at room temperature rather than solidifying.

Step 5: Analyze Option (D)

Unsaturated fats contain fewer hydrogen atoms than saturated fats for the same number of carbon atoms because of the presence of double bonds.

Step 6: Identify the Correct Statement

Based on the analysis, Option (B) is true: Unsaturated fats have double bonds in their fatty acid chains.

Key Concepts

Fatty acid chains

Fatty acid chains are long strings of carbon atoms bonded to hydrogen atoms. They are a fundamental part of fats and oils, acting as the building blocks.

• Saturated fats have fatty acid chains with only single bonds between carbon atoms.
• Unsaturated fats, however, have one or more double bonds in their fatty acid chains.

These chains determine many of the fat's properties, like its state at room temperature and its health benefits.

Double bonds

Double bonds in fatty acid chains play an important role in defining unsaturated fats. A double bond occurs when two carbon atoms share two pairs of electrons.

• These double bonds create a kink in the fatty acid chain, preventing the molecules from packing tightly together.
• This loose structure causes unsaturated fats to generally stay liquid at room temperature.
• Saturated fats, lacking double bonds, tend to be solid.

The presence of double bonds also means that unsaturated fats have fewer hydrogen atoms compared to saturated fats.

Plant fats

Plant fats are fats derived from plants, and they are typically unsaturated fats. Examples include olive oil, sunflower oil, and avocado oil.

• These fats are generally healthier than animal fats, which are often saturated.
• Plant fats can help lower bad cholesterol levels, reducing the risk of heart disease.
• They remain liquid at room temperature due to the double bonds in their fatty acid chains.

Including more plant fats in your diet can promote better overall health.