Lipids and Fatty Acids Overview

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Questions and Answers

What is the correct way to denote a fatty acid with 16 carbons and one double bond located on the 9th carbon?

16:1D9 (correct)

C16:1D9

16:1D9C

C16:1D8

Which configuration of unsaturated fatty acids contributes to kinks in the fatty acid tail?

Trans configuration

Saturated configuration

Omega-3 configuration

Cis configuration (correct)

How do melting points of fatty acids generally change with chain length?

They increase with longer chains (correct)

They remain constant regardless of chain length

They fluctuate unpredictably

They decrease with longer chains

Which classification of lipids focuses on their role in biological systems?

By function Signup and view all the answers

What is true about the classification of lipids?

Lipids may exist in multiple classification groups Signup and view all the answers

What effect do cis double bonds have on the physical properties of fatty acids?

Lower melting point Signup and view all the answers

Which of the following is an example of how lipids can be classified by their structure?

Phospholipids, glycolipids Signup and view all the answers

What is the significance of counting double bonds in fatty acids during nomenclature?

It impacts their melting points Signup and view all the answers

What is the primary function of triglycerides?

Energy storage, buoyancy, and thermal insulation Signup and view all the answers

Which of the following statements about phosphoglycerides is true?

They contain a phosphate group and a polar head. Signup and view all the answers

What distinguishes galactolipids from phospholipids?

Galactolipids include a glycosidic bond to glycerol. Signup and view all the answers

How do sphingolipids differ from other types of lipids mentioned?

They are based on sphingosine. Signup and view all the answers

Which characteristic of triglycerides contributes to their function in buoyancy?

They are low density. Signup and view all the answers

Why are storage lipids, like triglycerides, considered neutral?

They do not have a net charge and do not interact with water. Signup and view all the answers

What type of reaction is involved in the formation of triglycerides?

Esterification Signup and view all the answers

What is a common feature of glycerolipids?

They are composed of glycerol and fatty acids. Signup and view all the answers

What characteristic defines lipids?

They are a broad class of molecules that are insoluble in water. Signup and view all the answers

What is one of the main roles of lipids in biological systems?

They provide energy storage. Signup and view all the answers

Which statement about fatty acids is correct?

Fatty acids have a hydrophilic 'head' and a hydrophobic 'tail'. Signup and view all the answers

Which type of lipid is derived from sterols?

Oestrogen Signup and view all the answers

What property distinguishes amphipathic lipids from hydrophobic lipids?

Amphipathic lipids contain both water-soluble and water-insoluble groups. Signup and view all the answers

How are unsaturated fatty acids geometrically characterized?

They can adopt either cis or trans configurations. Signup and view all the answers

What is true about the carbon atoms in typical fatty acid chains?

They can vary in number from 6 to 36. Signup and view all the answers

What aspect of fatty acids causes kinks in their chains?

Cis double bonds. Signup and view all the answers

Study Notes

Lipids

Lipids are a broad class of molecules that are insoluble in water (e.g. waxes, oils, fats).
They are either hydrophobic, fully water hating/insoluble in water, or amphipathic, with both water soluble and water insoluble groups on one molecule.
Lipids play a significant role in energy storage, biomembranes, signaling, and enzymatic co-factors.

Fatty Acids

They contain a hydrophilic "head" and a hydrophobic "tail".
Usually contain 12 to 24 carbons, an even number only.
They can be subdivided into saturated, monounsaturated and polyunsaturated.
Unsaturated fatty acids can have two configurations based on the cis/trans arrangement of the double bonds.
Cis double bonds cause kinks in the chain, due to restricted rotation around the double bonds.

Fatty Acid Nomenclature

Standard: The nomenclature includes the chain length, number of double bonds, and the position of the first double bond. Example: 16:1Δ⁹ cis, 16:1Δ⁹ hexadecenoic acid (palmitoleic acid).
Omega: The omega system numbers the carbon atoms starting from the terminal CH3 group.

Melting Points

Melting points are influenced by the chain length and the presence of double bonds.
Longer chains have higher melting points.
Cis double bonds reduce the melting point due to the kinks in the tail, leading to a less compact structure.

Lipid Classification

Lipids can be classified by synthetic pathway, function, structure, and chemical composition.
Different criteria can lead to overlapping categories.

Glycerolipids

Composed of glycerol and fatty acids.
Glycerol is a 3-carbon polyalcohol.
Triglycerides are a class of glycerolipids, used for energy storage, buoyancy, and thermal insulation.

Phosphoglycerides

Glycerol, fatty acids, phosphate group, and a polar head group.
Important component of biomembranes.

Galactolipids

They contain galactose linked to glycerol by a glycosidic bond, with linoleic acid as the main fatty acid.
They are NOT phospholipids.

Sphingolipids

Based on sphingosine.
Can be phospholipids, simple or complex.

Difference between storage and membrane lipids

Storage lipids are neutral to store energy efficiently.
Membrane lipids are polar to form biomembranes and interact with the aqueous environment.

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Description

Explore the fascinating world of lipids and fatty acids in this quiz. Learn about the structure, types, and nomenclature of these essential biomolecules. Test your knowledge on how lipids function in energy storage and cellular signaling.