Biochem Chapter 8

Which of the following four fatty acids has the highest melting point? 1. CH3CH2CH2CH2CH2COOH 2. CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH 3. CH3CH2CH2CH2CH2CH2CH2COOH 4. CH3CH=CHCH2CH2COOH

2. CH3CH2CH2CH2CH2CH2CH2CH2CH2COOH

Which of the following four fatty acids has the lowest melting point? 1. CH3CH2CH2CH2CH2COOH 2. CH3CH2CH2CH2CH2CH2CH2CH 2CH2COOH 3. CH3CH2CH2CH2CH2CH2CH2COOH 4. CH3CH=CHCH2CH2COOH

4

Which of the following is not a lipid-soluble vitamin? A. Ascorbic Acid B. Cholicalciferol C. Vitamin K D. Retinol E. Tocopherol

A)

Which of the following is NOT a product of saponification of a triglyceride

A. Long chain fatty alcohols.

Which of the following compounds yields the most energy per gram? A. triacylglycerols B. carbohydrates C. proteins D. They all yield about the same amount of energy per gram.

A. triacylglycerols

Which of the following treatments would be most useful in separating an integral membrane protein from the lipid component of a cell membrane?

Add a detergent

How do the membranes of plant and animal cells compare?

Animal cell membranes tend to be more rigid than those of plant cells.

Liposomes are:

Artificial membrane-bounded structures used to deliver medications.

Which of the following is not true? A. Receptors are often invaginated into the cell after binding to their specific molecule. B. A given receptor type is present at a constant level on the outside of a cell C. In certain disease states, the level of a given receptor is increased or decreased D. Binding of receptors to ligands sometimes shows hyperbolic binding curves

B)

Which of the following is a metabolic precursor of prostaglandins & leukotrienes? A. vitamin A. B. arachidonic acid. C. sphingomyelin. D. cholesterol.

B) arachidonic acid

Which of the following lipid molecules possess a different fundamental structural make-up from the others? A. Fatty acids B. Cholesterol C. Triglycerides D. Sphingolipids E. Glycolipids

B. Cholesterol

Which of the following is not a function or characteristic of membrane proteins?

Blood clotting

What characteristic is most used to define lipids? A. ionic charge B. melting point C. solubility D. ability to bind metal ions

C. solubility

Which of the following groups is not present in a phosphatidic acid?

Choline

Which of the following groups is not present in lecithin?

Choline Fatty acids Glycerol AND Phosphate they all are

Which of the following statements concerning active transport is true? A. It takes place in the same direction as a concentration gradient. B. It requires no expenditure of energy by the cell. C. It can be compared to water running downhill. D. A membrane-associate protein must be involved.

D)

Which of the following does not belong in the list? A. Retinol B. Vitamin A C. beta-carotene D. Cholesterol

D) Cholesterol

A major difficulty in extracting receptor proteins from membranes is that A. it is difficult to remove the proteins from the membrane without denaturation B. there may be very few molecules of the protein in a cell C. receptor proteins tend to have high molecular weights D. all of these

D. All of these

The following lipid vitamin has important involvement with calcium ions: A. A B. D C. E D. K E. More than one reacts with calcium ion.

E)

The mechanism of membrane transport may involve the following: A. ATP hydrolysis. B. Conformation change of membrane proteins. C. Phosphorylation or dephosphorylation of membrane proteins. D. ATP hydrolysis and conformation change of membrane proteins. E. All of these are correct.

E)

The key reaction of eyesight (in dim light) involving vitamin A is: A. Reaction of the protein complex called Rhodopsin. B. A cis-trans isomerization of a double bond. C. Bleaching of a pigment in the retina. D. Reaction of Rhodopsin and cis-trans isomerization of a double bond. E. All of these.

E) All of these

Glycoproteins on the cell surface are involved in this type of function: A. Cell identification B. Receptor sites C. Immune function D. Cell identification and receptor sites E. All of these are correct.

E) All of these are correct

Saponification is the hydrolysis of a(n)

Ester bonds

Which of the following alcohols is never found in phosphatides?

Ethanolamine Serine Inositol Sugars ^^^All of these can be components of phosphatides.

T or F: Unsaturated fatty acids lead to higher levels of LDL than saturated fatty acids do

F

T or F: Membranes are generally symmetrical, i.e., the outer face is composed of the same number and types of phospholipids as the inner face.

False

T or F: Plants need cholesterol in their membranes to counteract the rigidity of the cell wall.

False

T or F: When a membrane reaches its transition temperature, integral membrane proteins dissociate from the bilayer.

False

Which of the following is true?

Fatty acids with an odd number of carbons are more rare than those with an even number

Vitamin E has all of the following properties, except:

It can be made in the sunshine

How does cholesterol affect membrane fluidity

It tends to decrease the fluidity.

Which of the following is the best phrase to describe the modern view of membrane structure?

Membranes are a fluid mosaic of lipids and proteins.

Glycolipids are particularly important in these structures

Membranes, the brain and the nervous system

Sphingolipids are particularly important in these structures

Membranes, the brain and the nervous system

Phospholipids are particularly important in these structures:

Membranes. Lipoproteins. The brain and nervous system. Membranes, the brain and the nervous system. ^^^All of these are correct.

The difference between active transport and passive transport is that:

One requires expenditure of energy by the cell and the other does not.

Which of the following groups is not present in a cerebroside?

Phosphate

Which of the following would not be enriched on the outer side of the lipid bilayer compared to the inner side?

Phosphoacylglyerol

Which of the following is not a characteristic of most fatty acids?

Presence of trans double bonds

Which of the following methods of transport across a membrane does not require a protein?

Simple diffusion

Which of the following groups is not present in sphingomyelin?

Sugar

Glycolipids are characterized by containing the following non-lipid component:

Sugars

Cell membranes typically display asymmetry. What does this mean?

The two leaves of a bilayer contain different collections of lipids and proteins.

What distinguishes primary from secondary active transport?

The type of linkage to ATP hydrolysis

Which of the following best describes lipids' solubility in water?

They are typically insoluble. like your love life, nonexistent.

How does the presence of cis double bonds in fatty acids affect membrane fluidity?

They tend to increase the fluidity.

I find that briefly washing cells in a buffered solution at pH 11 is effective for isolating a cell membrane-associated hormone receptor. (A standard growth solution for the cells is pH 7.) Which of following best fits this description?

This is a peripheral membrane protein that probably interacts with membrane phospholipids using lysine-mediated salt bridges.

T or F: Cholesterol is particularly important as a component of animal membranes.

True

T or F: Lipids differ from most other biomolecules because they are defined on the basis of solubility, rather than on their chemical structure.

True

There are likely to be huge stores of lipid vitamins in healthy animals. (True or False)

True

The vitamin classified as fat soluble rather than water soluble is:

Vitamin A

These two lipid vitamins are often found in membranes:

Vitamin A & E

Rickets is caused by a deficiency in:

Vitamin D

The following lipid vitamin is often used to preserve foods from spoiling:

Vitamin E

The vitamin needed for blood coagulation is:

Vitamin K

Facilitated diffusion requires:

a carrier protein to which the transported substance binds

Biological waxes are composed of

a fatty acid and a long-chain alcohol

In the operation of the sodium-potassium pump

a membrane protein is phosphorylated with ATP as the source of the phosphate group

Which of the following cell types contains cholesterol?

animal

Unsaturated fatty acids usually have ____ double bonds.

cis

Which property has not been observed for membrane proteins?

energy storage

What kinds of bonds do lipase break in order to release fatty acids from triacylglycerols?

esters

Passive transport is the same as:

facilitated diffusion

Which of the following molecules is not amphipathic?

glucose

With what compound are fatty acids reacted to make a fat or oil?

glycerol

What does amphipathic mean?

having both hydrophilic and hydrophobic regions

Membrane lipids in a lipid bilayer are held together by

hydrophobic interactions

The association of membrane proteins with lipids in the membrane bilayer always involves ...

hydrophobic interactions

Where can membrane proteins be located?

in either position (meaning entirely within the membrane or on the surface)

Aspirin produces most of its analgesic effects by:

inhibiting the synthesis of prostaglandins

The freeze-fracture technique of electron microscopy is useful in studying membrane structure because

integral membrane proteins can be seen in association with one leaflet of the lipid bilayer

The order-disorder transition (melting) in membranes

is cooperative can be monitored by fluorescence techniques can be monitored by spin labeling ^^^all of these

A useful method for studying membrane proteins in place in the membrane is:

nuclear magnetic resonance

In the sodium-potassium pump:

sodium is transported out of the cell and potassium into the cell, both against concentration gradients

The myelin sheaths of neurons typically contain large amounts of

sphingolipids

The degree of membrane fluidity depends on

the percentage of unsaturated fatty acids

In the fluid mosaic model of membrane structure:

the proteins "float" in the lipid bilayer

Which of the following is true? A. Fatty acids with trans double bonds may be particularly unhealthy because they increase the ratio of LDLs to HDLs. B. A fatty acid with 14 carbons and one trans double bond will behave more like a saturated fatty acid with 14 carbons than will an unsaturated fatty acid with a cis double bond. C. Fatty acids with trans double bonds can be formed by hydrogenation reaction of polyunssaturated fatty acids D. fatty acids with trans double bonds tend to have higher melting points than those with cis double bonds all else being equal

they all are.

How many hydroxyl groups does a molecule of glycerol have?

three

Which of the following lipids is not found in biological membranes?

triacylglycerols

T or F: Glycolipids on the surface of cells are especially important as cell markers.

true

T or F:Multiple sclerosis is characterized by destruction of the myelin sheath

true

T or F The fatty acids in both triacylglycerols and in phosphoacylglycerols vary.

truu.

The distribution of lipids in membranes is

uneven, with bulkier molecules on the exterior

T or F: Fatty acids with multiple double bonds are usually conjugated

yeeet