Mastering Biology Chapter 6 Lipids Flashcards

Questions and Answers

The presence of many C-C and C-H bonds causes fats to be...

Both (a) and (b) (correct)

Both (b) and (c)

Low in energy

Insoluble in water

Rich in energy

The highlighted part of this molecule is derived from...

Fatty acid

Cholesterols

Glycerol (correct)

Aniline

Guaiacol

In fat synthesis, and fatty acids combine to make fats plus .

Esters; phosphate

Glucose; phosphate

Esters; water

Glycerol; water (correct)

Phosphate; glycerol

In the reaction that builds a fat, groups react with groups.

Hydroxyl; carboxyl Signup and view all the answers

Triglycerides vary with respect to the number of...

Both (b) and (c) Signup and view all the answers

A food company hydrogenated a barrel of fat. The treatment...

Both (a) and (d) Signup and view all the answers

The most unsaturated fats have...

The most double bonds Signup and view all the answers

What do DNA, proteins, and fats have in common?

They contain carbonyl groups Signup and view all the answers

Which statement most accurately explains why cholesterol and phospholipids are amphipathic but fats are not?

Cholesterol and phospholipids contain both hydrophilic and hydrophobic regions; fats are primarily hydrophobic. Signup and view all the answers

A phospholipid is a _____

Nonpolar lipid molecule that is made amphipathic by the addition of a phosphate. Signup and view all the answers

What region of a steroid is hydrophilic?

The terminal hydroxyl group. Signup and view all the answers

Phospholipids and triglycerides both _____

Have a glycerol backbone. Signup and view all the answers

Lipids _____

Are insoluble in water. Signup and view all the answers

Steroids are considered to be lipids because they _____

Are not soluble in water. Signup and view all the answers

Molecules that are amphipathic must contain _____

Both hydrophilic and hydrophobic regions. Signup and view all the answers

Lipids are insoluble in water because _____

They contain nonpolar C-C and C-H bonds. Signup and view all the answers

Which of the following is true of membrane lipids?

They contain a hydrophilic head group and a hydrophobic tail. Signup and view all the answers

In an experiment involving planar bilayers, what can you conclude if the right side tests negative for ions?

Ions cannot cross planar bilayers. Signup and view all the answers

Which aspect of phospholipids is most important to the formation of bilayers?

They are amphipathic. Signup and view all the answers

Which of the following increases the strength of hydrophobic interactions in lipid bilayers?

Increasing length of the hydrocarbon chains Signup and view all the answers

Which of the following crosses lipid bilayers the fastest?

A small, nonpolar molecule like oxygen (O2) Signup and view all the answers

Which of the following crosses lipid bilayers the slowest?

A sodium ion Signup and view all the answers

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

CO2 Signup and view all the answers

Decreasing the saturation of the fatty acid chains on a particular type of phospholipid would result in the formation of _____

More fluid bilayers. Signup and view all the answers

Which term best describes the type of membrane protein in the figure?

Integral Signup and view all the answers

For the study shown in the figure, what is the most appropriate control?

Instead of a cell, use an artificial membrane composed only of pure phospholipids. Signup and view all the answers

Where would you most likely find an integral membrane protein?

Spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell. Signup and view all the answers

When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that _____

The hydrophobic interactions that hold the membrane together are weakest at this point. Signup and view all the answers

When a membrane is freeze-fractured, the bumps seen on the fractured surface of the membrane are _____

Integral proteins. Signup and view all the answers

Study Notes

Lipids Overview

Fats are rich in energy due to numerous C-C and C-H bonds and are insoluble in water.
Phospholipids feature a hydrophilic head and a hydrophobic tail, making them amphipathic.

Fatty Acids and Glycerol

Glycerol is derived from fatty acids, which are key components in fat synthesis where glycerol and fatty acids yield fats and water.
Fats are formed through the reaction of hydroxyl and carboxyl groups.

Triglycerides

Triglycerides differ in the number of carbon atoms and the presence of double bonds in their hydrocarbon tails.

Hydrogenation

Hydrogenation of fats results in decreased fluidity and higher saturation levels, affecting the structure of fatty acid tails.

Unsaturated Fats

The most unsaturated fats possess the highest number of double bonds, impacting their properties.

Common Features of Macromolecules

DNA, proteins, and fats contain carbonyl groups, representing a shared molecular feature.

Amphipathic Molecules

Cholesterol and phospholipids are amphipathic due to their dual hydrophilic and hydrophobic regions, unlike fats which are primarily hydrophobic.
Molecules must contain both hydrophilic and hydrophobic regions to be classified as amphipathic.

Solubility and Permeability

Lipids, including steroids, are characterized by their insolubility in water due to their nonpolar bonds.
Membrane lipids are amphipathic, allowing for the formation of bilayers that regulate permeability to substances.

Membrane Structure

Short, saturated hydrocarbon tails in phospholipids lead to less permeable membranes, counteracting the effects of tail length on permeability.
When phospholipids and water are mixed, tiny vesicles filled with water may form upon mechanical shaking.
Ions cannot cross planar bilayers, confirming the selective permeability of membranes.

Membrane Proteins

Integral membrane proteins span across the bilayer, with portions exposed inside and outside the cell, contributing to membrane stability and function.
Freeze-fracture studies reveal structural aspects of membranes, with bumps indicating the presence of integral proteins.

Molecular Movement

Small nonpolar molecules, like oxygen (O2), pass through lipid bilayers rapidly, while ions such as sodium move across the bilayer slowly.
The permeability of bilayers can be influenced by the saturation of fatty acid chains, with more fluid bilayers resulting from decreased saturation.

Experimental Controls

In studies involving membrane properties, using a pure phospholipid artificial membrane can help isolate effects from experimental artifacts, confirming observed phenomena are attributable to lipid behavior.

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Description

Test your knowledge on lipids with these flashcards from Chapter 6 of Mastering Biology. Each card presents key concepts related to fats, glycerol, and their properties. Perfect for quick review and better retention of important biological terms.