Biochem Test 1

Which is not a fat-soluble vitamin?

Vitamin C

Which vitamin is not strictly a vitamin because it can be synthesized in the body from cholesterol?

Vitamin D

Which statement is not true?

Vitamin E is an oxidating agent, oxiding the unsat. Side chain in fatty acid

________ are the simplest hydrolyzable lipids

Waxes

A sphingomyelin has three nonpolar side chain tails and one polar head

false

An individual can survive on a completely fat-free diet

false

Fats contain a larger percentage of unsaturation in their structures than oils do.

false

High-density lipoproteins (HDLs) transport cholesterol from where it is synthesized, to the tissues.

false

Hydrolysis of the triacylglycerol below provides the indicated products

false

In order for cholesterol to be transported from where it is synthesized in the liver to the tissues, it combines with phospholipids and proteins to form small water-soluble spherical particles called lipozymes

false

Lipids are defined as biomolecules that contain fatty acids as part of their structure.

false

Lipids are soluble in organic solvents and aqueous solutions.

false

Phosphoacylglycerols are less soluble in water than triacylglycerols.

false

Soap is prepared by the acid hydrolysis (saponification) of a triacylglycerol.

false

The molecule below is an omega-9 fatty acid. CH3(CH2)9CH=CH(CH2)7COOH

false

Triglycerols form lipid bi layers.

false

Eicosanoids are a group of biologically active compounds containing 20 carbon atoms derived from the fatty acid arachidonic acid.

true

When phospholipids are mixed with water, they assemble in an arrangement called a lipid bilayer, with the ionic heads oriented on the inside and the nonpolar tails on the outside

false

Lipids come in a wide variety of structures and have many different functions

true

Prostaglandins are a group of carboxylic acids that contain a five-membered ring, and are responsible for inflammation.

true

Saturated fatty acids have no double bonds in their long hydrocarbon chains

true

Some lipids and proteins on the cell membrane surface are bonded to carbohydrates, forming glycolipids and glycoproteins.

true

The coating that surrounds and insulates nerve cells, the myelin sheath, is particularly rich in sphingomyelins, and is vital for proper nerve function.

true

The compound below is an example of a simple triacylglycerol.

true

The three-dimensional structure of a trans triacylglycerol shows its similarity to saturated triacylglycerols

true

Unsaturated fatty acids are sometimes classified as omega-n acids, where n is the carbon at which the first double bond occurs in the carbon chain, beginning at the end of the chain that contains the CH3 group.

true

Vitamins are organic compounds required in small quantities for normal metabolism.

true

Although biofuels are prepared from renewable resources such as vegetable oils and animal fats, they still burn to form CO2, a gas that contributes to global warming.

true

How many fatty acids are required to form a triacylglycerol?

3

Triacylglycerols are stored in ________ cells below the skin and concentrated in some regions of the body.

Adipose

Which compound has the highest melting point?

CH3(CH2)14COOH

What hydrolysis products are formed when the wax CH3(CH2)18COO(CH2)17CH3 is treated with aqueous sulfuric acid?

CH3(CH2)18COOH + CH3(CH2)16CH2OH

What wax is formed from palmitic acid [CH3(CH2)14COOH] and the alcohol CH3(CH2)21OH?

CH3(CH2)COO(CH2)21CH3

COmplete metabolism of a triaglycerol yields chich of the following?

CO2, H2O and a great deal of energy

Testosterone (structure shown) is an androgen that control the development of secondary sex characteristics in males. Which of the following functional groups is not present in testosterone?

Carboxylic acid

Which is not an anabolic steroid?

Cortisone

As the number of double bonds in a fatty acid increases, the melting point ________.

Decreases

The structure of lipids is?

Dominated by hydrophobic regions

Which is a nonhydrolyzable lipid?

Eicosanoid

Prostaglandins and leukotrienes are two types of ________.

Eicosanoids

Hydrolysis of triacylglycerols in the body occurs with the aid of which reagents?

Enzymes

What functional group is contained in most hydrolyzable lipids?

Ester

What process is used to move large polar molecules and ions, such as Cl- and HCO3-, through a cell membrane, traveling from the side of higher concentration to the side of lower concentration?

Facilitated transport

Fats and oils are structurally both triacylglycerols, but fats are solids at room temperature and oils are liquids at room temperature. Which statement best describes the reason for their difference in physical state?

Fats contain a higher percentage of saturated fatty acids than oils do, and therefore have higher melting points than oils

The compound shown below is best classified as what type of lipid?

Fatty acid

Triacylglycerols, or triglycerides, are triesters formed from glycerol and three ________ molecules.

Fatty acid

Which structural feature is not found in sphingomyelins?

Gylcerol backbone

Cetyl palmitate is a component of spermaceti wax isolated from the heads of sperm whales, and is used in cosmetics. In which solvent would cetyl palmitate be expected to have the greatest solubility?

Hexane

The block diagram for a phosphoacylglycerol (glycerophospholipid) is shown below. Phosphoacylglycerols can interact with both water and other lipids, and therefore are well suited for their role in the lipid bilayer of cell membranes. Which statement best explains this behavior?

Hydrophobic and hydrophobic regions

The contents on a box of cupcakes lists partially hydrogenated soybean oil. Partial hydrogenation of soybean oil has what effect?

It decreases the percent of unsaturated that is present.

Lovastatin (structure shown) was the first statin drug to be marketed and used for lowering blood cholesterol. Which of the following functional groups is not present in lovastatin?

Ketone

Cell membranes are made up of a structure called a(n) ________

Lipid bilayer

Which type of fatty acid is most common is olive oil?

Monounsaturated

Which is not an example of a lipid?

Phenol

Which is a hydrolyzable lipid?

Phosphoacylglycerol

What is the main component of the cell membrane?

Phospholipids

Which statement concerning lipid functions is incorrect?

Plants and animals use waxes for insulation

Which is not true about prostaglandins?

Prostaglandins decrease inflammation

Unlike most oil, which type of fatty acid is most common in coconut oils?

Saturated

Which of these groups of compounds are phospholipids?

Sphingomyelins

What is the structure of arachidic acid?

The very long chain

Which is a hydrolyzable lipid?

Triacylglycerol

Waxes are formed from the reaction between which two types of compounds?

a fatty acid and a high molecular weight alcohol

Two common types of phospholipids are ________ and ________.

phosphoacylglycerols; sphingomyelin

Aldosterone regulates blood pressure and volume by controlling the concentration of Na+ and K+ in body fluids.

true

Glycerol, shown below, is a component of triacylglycerols. In which solvent would glycerol be expected to have the greatest solubility?

water

Lipids known as ________ provide a protective coating for plants and animals.

waxes