Lipid Metabolism and Fatty Acid Synthesis

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a characteristic of lipids?

Polar compounds

Soluble in water

Electrical conductors

Soluble in organic solvents (correct)

What is the primary function of lipids in the body?

Nucleic acid synthesis

Concentrated sources of energy (correct)

Protein synthesis

Cell signaling

What is the role of lipids in thermoregulation?

Heat gain

Sweat production

Heat loss

Insulation (correct)

What is the classification of lipids that includes cholesterol and hormones?

Sterols Signup and view all the answers

What is the characteristic of fatty acids in natural fats?

Contain an even number of carbon atoms Signup and view all the answers

What is the type of fatty acid with one double bond?

Monounsaturated fatty acid Signup and view all the answers

What is the role of lipids in the absorption of fat-soluble nutrients?

Lipids provide a means for the absorption of fat-soluble nutrients Signup and view all the answers

What is the function of lipids in the structure of cells?

Lipids are structural elements of cell membranes Signup and view all the answers

What is the primary function of insulin in fatty acid synthesis?

Activate ACC Signup and view all the answers

What is the primary function of glucagon in fatty acid synthesis?

Inhibit ACC Signup and view all the answers

What is the characteristic of fatty acids?

They have a alkyl chain with a terminal carboxyl group Signup and view all the answers

What is the role of fatty acid synthase (FAS) in lipogenesis?

Synthesize fatty acids Signup and view all the answers

What is the role of acyl carrier protein (ACP) in fatty acid biosynthesis?

Act as a cofactor Signup and view all the answers

What is the primary function of lipogenesis?

Synthesis of fatty acids from carbohydrates and proteins Signup and view all the answers

What is the role of phosphatidylserine in the body?

It plays a role in apoptosis, programmed cell death Signup and view all the answers

What is the typical number of cycles performed to form palmitic acid?

7 Signup and view all the answers

What is the starting point for elongation of fatty acid chains in the smooth endoplasmic reticulum?

Both A and B Signup and view all the answers

What is the function of acetylcholine in the body?

It is important in nervous transmission Signup and view all the answers

What is the role of NADPH in fatty acid elongation?

Supplies electrons Signup and view all the answers

What is the location of glycolipids in the cell?

Outer leaflet of the plasma membrane Signup and view all the answers

What is the role of desaturases in fatty acid synthesis?

Desaturate fatty acid chains Signup and view all the answers

What is the role of citrate in lipogenesis?

It activates the enzyme ACC Signup and view all the answers

What is the characteristic of phospholipids?

They are amphipathic Signup and view all the answers

What is unique about the brain's ability to produce fatty acids?

It can produce very-long-chain fatty acids Signup and view all the answers

What is the function of cardiolipin in the cell?

It is a major lipid of mitochondrial membranes Signup and view all the answers

Study Notes

Lipid Metabolism Overview

Lipids are non-polar, hydrophobic compounds that are insoluble in water but soluble in organic solvents
Lipids are synonymous with "fat" and include phospholipids, sterols, and others

Functions of Lipids

Concentrated sources of energy (1g = 9.3 kcal)
Involved in thermoregulation
Enable absorption of fat-soluble nutrients (e.g., sterols, vitamins)
Structural elements of cell and subcellular components
Components of lipoproteins, hormones, and prostaglandin synthesis
Act as electrical insulators in myelinated nerves

Classification of Lipids

Simple: Acylglyceroles, Waxes
Complex: Phospholipids, Glycolipids, Sterols
Lipid Derivatives: Eicosanoids, Polyisoprenoids, Ketone bodies

Fatty Acids

Aliphatic carboxylic acids
Occur in the body mainly as esters in natural fats and oils
Can be saturated or unsaturated
Typically contain an even number of carbon atoms
Monounsaturated fatty acids: contain one double bond
Polyunsaturated fatty acids: contain two or more double bonds

Fatty Acid Synthesis (Lipogenesis)

Occurs primarily in the liver and lactating mammary glands
Uses ATP and NADPH
Totally cytosolic process
Insulin activates ACC, while glucagon inhibits ACC

Synthesis of Fatty Acids

Palmitic acid (16:00) synthesis occurs through a series of reactions
Involves the repeated addition of two-carbon units from malonyl-CoA to a growing fatty acid chain
Catalyzed by fatty acid synthase (FAS) and acyl carrier protein (ACP)
Each cycle adds two carbons to the growing fatty acid chain
Typically around 7 cycles are performed

Elongation of Fatty Acid Chains

Palmitate can be further elongated by the addition of two-carbon units in the smooth endoplasmic reticulum (SER)
Acyl-CoA or Malonyl-CoA molecules serve as the starting point for elongation
NADPH supplies the electrons
The brain has additional elongation capabilities, allowing it to produce very-long-chain fatty acids

Desaturation of Fatty Acid Chains

Enzymes (desaturases) present in the SER are responsible for desaturating long-chain fatty acids
Desaturation reactions require NADH, cytochrome b5, and its FAD-linked reductase

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the overview of lipids, their properties, functions, and synthesis. It includes topics such as protoplasmic and reserve lipids, energy sources, and thermoregulation.