Biology Chapter 11 Flashcards

Questions and Answers

Some lipid molecules are said to be amphipathic, meaning that they:

Carry a positive charge on one end and a negative charge on the other end

Have asymmetric carbons and can exist in left- and right‑handed forms

Are capable of moving rapidly from one side of a lipid bilayer to the other

Have a dual nature with part of the molecule being hydrophobic and the other part being hydrophilic (correct)

Unsaturated fatty acids have double bonds that are in the cis configuration. One of the consequences of this configuration is:

An alteration in the number of carbons in the molecule

An alteration in the charge of the molecule

Enhanced flexibility of the molecule

A bend in the molecule (correct)

In phosphoglycerides, fatty acids are esterified at:

A glycerol carbon and the phosphate group

C‑1 and C‑2 of glycerol (correct)

C‑1 and C‑3 of glycerol

Any two of the three glycerol carbons

Which statement does NOT describe a difference between archaeal membrane lipids and those of bacteria and eukaryotes?

Archaeal membrane lipids use a backbone other than glycerol Signup and view all the answers

Of the three major types of membrane lipids, which is NOT found in prokaryotes?

Cholesterol Signup and view all the answers

The fatty acid oleate contains 18 carbons and a cis double bond after C‑9. Which designation describes the composition and structure of oleate?

18:1 Signup and view all the answers

In biological systems, fatty acids usually contain an even number of carbon atoms. Which fatty acids are MOST common in biological systems?

Fatty acids with 16 and 18 carbons Signup and view all the answers

A triacylglycerol consists of fatty acids attached to:

One glycerol Signup and view all the answers

Fill in the blank for the fatty acid composition: $C_{18}H_{34}O_2$ is commonly known as _____

Oleate Signup and view all the answers

Which of the designations are accurate for the fatty acid?

18:2(Δ6,9) Signup and view all the answers

Fatty acids are carboxylic acids with a long, unbranched hydrocarbon chain. Classify the fatty acids as ___, _, or ___

Saturated, monounsaturated, polyunsaturated Signup and view all the answers

Match each fatty acid with its melting point:

This question would require specific melting points to match Signup and view all the answers

Which of the statements are true?

Cell membranes in cold tolerant winter wheat plants have a higher ratio of unsaturated fatty acids to saturated fatty acids than do cold intolerant wheat varieties Signup and view all the answers

Select the statements about fatty acid melting points that are true.

A saturated fatty acid with a greater molar mass has a higher melting point than a saturated fatty acid with a lower molar mass Signup and view all the answers

Which lipid or lipids must be obtained in the diet?

Essential fatty acids Signup and view all the answers

Which of the statements are true?

Triacylglycerols (triglycerides) are composed of fatty acid residues and glycerol Signup and view all the answers

A glycerol molecule and three butyric acid molecules are shown. Delete atoms and add bonds as necessary to form a triacylglycerol (triglyceride). Draw only the triacylglycerol product.

This is a drawing task. Signup and view all the answers

Classify the characteristics of triacylglycerols and phosphoglycerides:

Both have a glycerol backbone, but triacylglycerols have three fatty acids while phosphoglycerides have two. Signup and view all the answers

Classify each structural feature as characteristic of a sphingolipid or a phosphoglyceride:

Requires identification of features. Signup and view all the answers

Select the molecules that can form the polar head group of phospholipids.

Serine Signup and view all the answers

Which properties are true of this lipid?

The lipid has a polar head group Signup and view all the answers

Glycerophospholipids (phosphoglycerides) are components of cell membranes. They are composed of a glycerol molecule with two fatty acids attached to the first and second carbon atoms, and a polar (hydrophilic) group attached through a phosphodiester linkage to the third carbon atom. Match each structure with the correct name.

This requires specific structures for matching. Signup and view all the answers

Sort the descriptions into properties that describe either saturated phospholipids or unsaturated phospholipids.

Requires identifying properties. Signup and view all the answers

Select the molecules that contain sphingosine.

Molecule C Signup and view all the answers

Block diagrams representing the general structures of three lipid types are shown. Classify each block diagram as a triacylglycerol (triglyceride), glycerophospholipid (phosphoacylglycerol), or sphingophospholipid (sphingomyelin).

Requires viewing block diagrams. Signup and view all the answers

A glycolipid is:

A lipid molecule that contains at least one carbohydrate unit Signup and view all the answers

What basic ring structure is common to all steroids?

This requires the identification of the steroid ring structure. Signup and view all the answers

Is the molecule shown hydrophilic, hydrophobic, or amphipathic (amphiphilic)?

Hydrophobic Signup and view all the answers

What is the difference between docosahexaenoate (DHA) and 19,20-dihydroxydocosapentaenoate (19,20-DHDP)?

19,20-DHDP is more polar than DHA Signup and view all the answers

Study Notes

Lipid Characteristics

Amphipathic lipids have both hydrophobic and hydrophilic regions, allowing them to form structures like lipid bilayers.
Unsaturated fatty acids feature cis double bonds, which create bends in their structure, affecting their fluidity and flexibility.

Phosphoglycerides

In phosphoglycerides, fatty acids are esterified specifically at the C-1 and C-2 positions of the glycerol backbone.
Phosphoglycerides are integral components of cellular membranes, providing structural integrity and functionality.

Archaeal Membrane Lipids

Archaeal lipids differ from bacterial and eukaryotic lipids by using ether linkages instead of ester linkages, contributing to their stability in extreme environments.
Archaeal membranes may also contain branched hydrophobic tails and alternative backbones, enhancing resilience under harsh conditions.

Types of Fatty Acids

Cholesterol is not found in prokaryotes; instead, they contain phospholipids, phosphoglycerides, and glycolipids.
The fatty acid oleate, which has 18 carbons and a cis double bond, is designated as 18:1.
Fatty acids with 16 and 18 carbons are the most common in biological systems.
A triacylglycerol is formed by the attachment of three fatty acids to a single glycerol molecule, serving primarily as an energy storage form.

Melting Points and Fatty Acids

The melting point is affected by the saturation level of fatty acids; saturated fatty acids generally have higher melting points than their unsaturated counterparts.
A saturated fatty acid of greater molar mass has a higher melting point, indicating that longer-chain saturated fatty acids remain solid at room temperature more often than unsaturated ones.

Essential Fatty Acids

Essential fatty acids must be obtained through diet, contributing to various physiological functions.
Saturated fats are predominantly solid at room temperature, while unsaturated fats tend to be liquid.

Triacylglycerols vs. Phosphoglycerides

Triacylglycerols consist of three fatty acid chains, while phosphoglycerides contain only two fatty acids with a third carbon linked to a polar head group, often involved in membrane formation.
Migratory birds utilize triacylglycerols as a major energy source for long-distance flight.

Structural Features

Glycerophospholipids are recognized by their glycerol backbone linked to two fatty acids and a polar group via a phosphodiester bond.
Sphingolipids differ from phosphoglycerides in that they contain sphingosine, not glycerol.

Glycolipids

Glycolipids are lipids that include at least one carbohydrate unit, playing important roles in cell recognition and signaling.

Steroid Structure

All steroids share a common basic ring structure derived from a sterol precursor, contributing to their diverse biological roles.

Polar and Nonpolar Groups

Molecules with polar head groups and nonpolar tails are crucial for forming cell membranes, distinguishing between hydrophobic and hydrophilic regions for membrane integrity and function.
Certain lipids, like sphingomyelins, incorporate sphingosine and play vital roles in cellular activities and membrane dynamics.

DHA vs. 19,20-DHDP

19,20-DHDP is more polar than docosahexaenoate (DHA), indicating a difference in their solubility and interaction in biological systems.

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Description

Explore the key concepts of Chapter 11 with these flashcards. This chapter focuses on important biological molecules, including amphipathic lipids. Test your understanding of lipid structures and their functions in biological systems.

Biology Chapter 11 Flashcards

Questions and Answers

Some lipid molecules are said to be amphipathic, meaning that they:

Unsaturated fatty acids have double bonds that are in the cis configuration. One of the consequences of this configuration is:

In phosphoglycerides, fatty acids are esterified at:

Which statement does NOT describe a difference between archaeal membrane lipids and those of bacteria and eukaryotes?

Of the three major types of membrane lipids, which is NOT found in prokaryotes?

The fatty acid oleate contains 18 carbons and a cis double bond after C‑9. Which designation describes the composition and structure of oleate?

In biological systems, fatty acids usually contain an even number of carbon atoms. Which fatty acids are MOST common in biological systems?

A triacylglycerol consists of fatty acids attached to:

Fill in the blank for the fatty acid composition: $C_{18}H_{34}O_2$ is commonly known as _____

Which of the designations are accurate for the fatty acid?

Fatty acids are carboxylic acids with a long, unbranched hydrocarbon chain. Classify the fatty acids as _____, _____, or _____

Match each fatty acid with its melting point:

Which of the statements are true?

Select the statements about fatty acid melting points that are true.

Which lipid or lipids must be obtained in the diet?

Which of the statements are true?

A glycerol molecule and three butyric acid molecules are shown. Delete atoms and add bonds as necessary to form a triacylglycerol (triglyceride). Draw only the triacylglycerol product.

Classify the characteristics of triacylglycerols and phosphoglycerides:

Classify each structural feature as characteristic of a sphingolipid or a phosphoglyceride:

Select the molecules that can form the polar head group of phospholipids.

Which properties are true of this lipid?

Sort the descriptions into properties that describe either saturated phospholipids or unsaturated phospholipids.

Select the molecules that contain sphingosine.

Block diagrams representing the general structures of three lipid types are shown. Classify each block diagram as a triacylglycerol (triglyceride), glycerophospholipid (phosphoacylglycerol), or sphingophospholipid (sphingomyelin).

A glycolipid is:

What basic ring structure is common to all steroids?

Is the molecule shown hydrophilic, hydrophobic, or amphipathic (amphiphilic)?

What is the difference between docosahexaenoate (DHA) and 19,20-dihydroxydocosapentaenoate (19,20-DHDP)?

Study Notes

Lipid Characteristics

Phosphoglycerides

Archaeal Membrane Lipids

Types of Fatty Acids

Melting Points and Fatty Acids

Essential Fatty Acids

Triacylglycerols vs. Phosphoglycerides

Structural Features

Glycolipids

Steroid Structure

Polar and Nonpolar Groups

DHA vs. 19,20-DHDP

Studying That Suits You

Description

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