Fatty Acids Overview

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Questions and Answers

What distinguishes a saturated fatty acid from an unsaturated fatty acid?

Saturated fatty acids contain no double bonds. (correct)

Saturated fatty acids are always cis.

Saturated fatty acids have one or more double bonds.

Saturated fatty acids consist of fewer carbon atoms.

What happens to the structure of fatty acids when a double bond is introduced?

The fatty acid retains its original confirmation.

The configuration may change to either cis or trans. (correct)

The fatty acid becomes saturated.

The number of hydrogen atoms increases significantly.

In terms of structural notation, what does the 'Δx' signify in cis/trans notation?

The number of carbon atoms in the chain.

The position of the double bond counting from the omega end.

The specific carbon at which the fatty acid is saturated.

The specific carbon-carbon bond location from the carboxyl end. (correct)

What effect does the cis configuration have on a fatty acid's molecular structure?

It bends the chain, restricting conformational freedom. Signup and view all the answers

How are omega fatty acids classified?

By the position of the double bond counting from the methyl end. Signup and view all the answers

What characterizes lipids in terms of solubility?

Insoluble in polar solvents Signup and view all the answers

Which of the following statements is true regarding double bonds in fatty acids?

They can be in either cis or trans configuration. Signup and view all the answers

What impact does the presence of double bonds have on the saturation of fatty acids?

It results in the fatty acid being unsaturated. Signup and view all the answers

Which of the following is NOT a category of lipids based on biochemical function?

Solvent lipids Signup and view all the answers

What is a characteristic of trans fatty acids in comparison to cis fatty acids?

They have the carbon atoms on opposite sides of the double bond. Signup and view all the answers

Which type of lipid can undergo saponification?

Triacylglycerols Signup and view all the answers

What is a characteristic of fatty acids?

Have a carboxylic acid group and a long hydrocarbon tail. Signup and view all the answers

What does the notation C18:1 indicate about a fatty acid?

18 carbon atoms and one double bond Signup and view all the answers

Which of the following fatty acid types has no double bonds?

Saturated Signup and view all the answers

Which of the following best describes nonsaponifiable lipids?

Do not react with water Signup and view all the answers

What type of interaction primarily occurs between the nonpolar tails of fatty acids?

London forces Signup and view all the answers

What structure do soaps form in solution?

Micelles Signup and view all the answers

Which type of phospholipid contains a glycerol backbone?

Glycerophospholipids Signup and view all the answers

What differentiates sphingolipids from glycerophospholipids?

Presence of sphingosine Signup and view all the answers

What role do phospholipids serve in food products like mayonnaise?

Emulsifying agents Signup and view all the answers

What is a common example of an emulsion that phospholipids help stabilize?

Mayonnaise Signup and view all the answers

Which part of the molecule does the term 'Phosphotidyl-' refer to?

Everything but the X Signup and view all the answers

What type of alcohol is typically found in glycolipids?

Sugar Signup and view all the answers

Which statement about sphingolipids is true?

They are found in myelin membranes. Signup and view all the answers

What is the primary function of lipoproteins in the bloodstream?

To transport lipids to various tissues Signup and view all the answers

Which of the following lipoproteins is considered 'bad cholesterol'?

LDL Signup and view all the answers

What is the recommended HDL level in mg/dL?

<blockquote> 40 </blockquote> Signup and view all the answers

Which type of steroid hormones are responsible for the development of secondary sex characteristics?

Sex Hormones Signup and view all the answers

Where are estrogens primarily produced in females?

Ovaries Signup and view all the answers

Which of the following components is a major part of very-low-density lipoprotein (VLDL)?

Triglycerides and Cholesterol Signup and view all the answers

What is the primary role of adrenal cortical steroids?

Regulation of metabolism and immune response Signup and view all the answers

What is the primary storage site for fat in the body?

Adipose tissue Signup and view all the answers

What is the primary function of the hormone progesterone?

Prepares the uterus for implantation Signup and view all the answers

Which compound is classified as an androgen?

Testosterone Signup and view all the answers

What are anabolic steroids mainly used for?

Promote muscle growth Signup and view all the answers

What role does aldosterone play in the body?

Regulates blood pressure and volume Signup and view all the answers

Which statement about eicosanoids is true?

They are synthesized in response to external stimuli. Signup and view all the answers

Which of the following is a function of prostaglandins?

Inhibit blood platelet aggregation Signup and view all the answers

What are cortisone and cortisol primarily used for?

As anti-inflammatory agents Signup and view all the answers

Which of the following describes the effect of aspirin and ibuprofen related to prostaglandins?

They block the synthesis of prostaglandins. Signup and view all the answers

Study Notes

Fatty Acids

Fatty acids are naturally occurring monocarboxylic acids
Fatty acids have a long hydrocarbon tail and a polar end ([COOH] group)
They are usually between 12 and 20 carbons long, with an even number of carbons
Short descriptions for fatty acids are based on their number of carbon atoms and double bonds (e.g., C18:0)
- C18:0 means 18 carbons, 0 double bonds
- C18:1 means 18 carbons, 1 double bond
Unsaturated fatty acids contain one or more alkenyl functional groups with a carbon double bond
Saturated fatty acids have no double bonds, all carbons have as many hydrogens as possible
The cis/trans conformation refers to the relative position of the carbon atoms on either side of the double bond
- Cis configuration: carbons are on the same side of the double bond
- Trans configuration: carbons are on opposite sides of the double bond
The omega (ω) notation indicates the position of the double bond counting from the methyl carbon of the chain
- ω-x means the double bond is on the xth carbon from the end of the chain

Lipids

Lipids are hydrophobic, nonpolar molecules
They are soluble in nonpolar solvents
They are insoluble in polar solvents, such as water
They are isolated from other biological molecules using nonpolar solvents

Categories of Lipids

Based on biochemical function:
- Energy-storage lipids: (triacylglycerol)
- Protective-coating lipids: (biological waxes)
- Membrane lipids: (phospholipids, sphingolipids, cholesterol)
- Emulsification lipids: (bile acids)
- Messenger lipids: (steroid hormones and eicosanoids)
Based on saponification:
- Saponifiable lipids: can be converted to smaller molecules by hydrolysis
  - Triacylglycerols, glycerophospholipids, spingophospholipids, spingoglycolipids, biological waxes
- Nonsaponifiable lipids: cannot be broken down into smaller units
  - Cholesterol, bile acids, steroid hormones, eicosanoids

Phospholipids and Glycolipids

Phospholipids form lipid bilayers
Glycerophospholipids:
- Similar to triglycerides, but one fatty acid is replaced with a phosphate
- An additional alcohol is attached to the phosphate
Sphingophospholipids (sphingolipids):
- Glycerol and one fatty acid from glycerophospholipids are replaced with sphingosine
- Found in the myelin membranes that insulate nerve cells
Glycolipids:
- Sphingolipids with sugars in the alcohol portion
Phospholipids are used as emulsifying agents
- Lecithin (phosphotidylcholine) is used as an emulsifying agent in mayonnaise
- An emulsifying agent stabilizes an emulsion (a colloidal suspension of one liquid in another)

Lipoproteins

Lipoproteins transport lipids through the bloodstream to tissues where they are stored, used for energy, or to make hormones
They are spherical particles with a polar surface and nonpolar inner core
Lipoproteins are classified based on their density:
- Chylomicrons: highest triglyceride content, lowest density
- VLDL (very-low-density lipoprotein): high triglyceride content
- LDL (low-density lipoprotein) "bad cholesterol": high cholesterol content
- HDL (high-density lipoprotein) "good cholesterol": high cholesterol content
- Recommended levels: HDL > 40 mg/dL, LDL < 100 mg/dL, total serum cholesterol < 200 mg/dL

Messenger Lipids

Messenger lipids are synthesized in one part of the body and elicit a response in another part
Steroid hormones:
- Sex hormones:
  - Estrogens (estradiol, estrone): control female development, regulate the menstrual cycle
  - Progestins (progesterone): "pregnancy hormone" prepares the uterus for implantation
  - Androgens (testosterone, androsterone): control male development
  - Anabolic steroids: synthetic androgen analogues that promote muscle growth, used by athletes, not permitted in sports
- Adrenal cortical steroids:
  - Aldosterone: regulates blood pressure and volume by controlling Na+ and K+ concentration
  - Cortisone and cortisol: anti-inflammatory agents, regulate carbohydrate metabolism
- Eicosanoids:
  - Prostaglandins: carboxylic acids with a five-membered ring, various biological activities
    - Responsible for inflammation
    - Decrease gastric secretions, inhibit platelet aggregation, induce uterine contractions, relax smooth muscles
  - Leukotrienes: 20 carbon atoms, derived from fatty acids
  - Both are very potent compounds, not stored, synthesized in response to external stimuli, act locally

Key Facts

Double bonds within fatty acid chains can be in a cis (same side) or trans (opposite side) configuration
Fatty acids are rarely found free in nature, usually part of lipids
The "phosphotidyl" part of the name describes the phosphate-containing part of a glycerophospholipid
Cholesterol is a lipid used to make bile salts, steroid hormones, and vitamin D
Aspirin and ibuprofen inhibit prostaglandin synthesis, relieving pain and inflammation

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Description

This quiz explores the fundamentals of fatty acids, including their structure, types, and nomenclature. Learn about saturated and unsaturated fatty acids, as well as the significance of their carbon chain lengths and double bonds. Dive into the cis/trans configurations and omega notation that characterize these important biomolecules.