Mastering Biology Chapter 3

Which of the following statements about hydrocarbons is false?

A) Hydrocarbons consist of atoms linked by single or double bonds.
B) Hydrocarbons can form straight, branched, or ringed structures.
C) Hydrocarbons contain only carbon and hydrogen atoms.
D) Hydrocarbons are inorganic compounds.

D) Hydrocarbons are inorganic compounds.

Which of the following statements regarding carbon is false?

A) Carbon has the ability to bond with up to six other atoms.
B) Carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons."
C) Carbon has a tendency to form covalent bonds.
D) Carbon has the capacity to form single and double bonds.

A) Carbon has the ability to bond with up to six other atoms.

Organic compounds…

always contain carbon

Two molecules are structural molecules. The difference between them is…

the location of a double-bonded oxygen atom

Which of the following statements about carbon skeletons is true?

A) Carbon skeletons may be arranged in rings.
B) Carbon skeletons are always linear and never branched.
C) Carbon skeletons only contain double bonds.
D) The length of carbon skeletons is always the same; it is the attachments that differentiate molecules.

A) Carbon skeletons may be arranged in rings.

Which element is closely associated with the field of organic chemistry?

carbon

What are the differences between carboxyl, methyl and carbonyl groups?

Look at chart in book

A hydroxyl group is

characteristic of alcohols.

Which of the following is a carboxyl group?

-COOH

Which of the following is an amino group?

-NH2

Which of the following statements about the functional groups of organic compounds is false?

All functional groups include a carbon atom.

Although the structures of the functional groups important to life (hydroxyl, carbonyl, carboxyl, amino, and phosphate) vary in chemical structure, they share one thing in common: They _____.

all are hydrophilic and increase the organic compound’s water solubility

Dehydration reactions __________. They do so by __________.

link monomers to form a polymer; removing a water molecule

Which of the following statements about the monomers and polymers found in living organisms is false?

Monomers are joined together by the process of hydrolysis.

The results of dehydration synthesis can be reversed by

hydrolysis.

What is the general function of enzymes within a cell?

to speed up chemical reactions.

Lactose is a disaccharide (two monosaccharides joined together). To metabolize lactose, individuals require an enzyme known as lactase. What is true about this reaction?

The reaction hydrolyzes the sugar.

The molecular formula of most monosaccharides represents a multiple of

CH2O.

Which of the following molecules is a carbohydrate?

A) C22H49O10N5
B) C45H84O8P4
C) C60H100O50
D) C51H98O6

C) C60H100O50

Carbohydrates are mainly used in our bodies _____.

as fuel

Which of the following sugars CAN be accurately represented by the formula C6H12O6?

possibly glucose or fructose

A disaccharide forms when

two monosaccharides join by dehydration synthesis.

High-fructose corn syrup is made from corn. The main carbohydrate in corn is a polysaccharide called

starch.

The production of high fructose corn syrup involves the hydrolysis of __________ from corn into __________, followed by its enzymatic conversion.

starch … glucose

Cellulose differs from starch in that

most animals cannot break down cellulose, whereas starch is easily digested.

Which of the following foods would contain the most starch?

A) celery
B) steak
C) liver
D) carrots

D) carrots

The storage form of carbohydrates is ________ in animals and ________ in plants.

glycogen; starch

Generally, animals cannot digest the linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?

Microorganisms in their digestive tracts hydrolyze the cellulose to glucose.

When you eat a plant, you derive energy from the stored __________, but not from the __________ component.

starch … cellulose

Double bonds are present in the majority of the fats of which of the following foods?

A) eggs
B) peanuts
C) lard
D) margarine

B) peanuts

What combination of fatty acids could you use to make a fat that is liquid at room temperature?

one palmitic acid, one stearic acid, and one oleic acid

The oil and vinegar in your salad dressing remain separate from one another due to the _____ properties of the oil.

hydrophobic

An oil may be converted into a substance that is solid at room temperature by

adding hydrogens, decreasing the number of double bonds in the molecules.

Fatty acids are

hydrophobic

What feature of fats makes them hydrophobic?

Fats have nonpolar hydrocarbon chains.

Lipids differ from other large biological molecules in that they _____.

are not truly polymers

A fatty acid containing at least one double bond is called _____.

unsaturated

The lipids that form the main structural component of cell membranes are _____.

phospholipids

Cholesterol belongs to which class of molecules?

lipids

Which statement correctly describes bonds of the secondary structure of proteins?

Secondary structure involves hydrogen bonding between atoms of the polypeptide backbone.

The primary structure of a protein is

the amino acid sequence of the polypeptide chain

The tertiary structure of a polypeptide refers to

the overall three-dimensional structure.

A protein containing more than one polypeptide chain exhibits the ________ level of protein structure.

primary, secondary, tertiary, and quaternary structure

Which of the following would be affected when a protein is denatured?

tertiary structure

Two proteins have the same number and type of amino acids. How is it that they can have different shapes and therefore different functions?

The order in which the amino acids are arranged differs between the two proteins.

DNA carries the instructions for building _____, and these instructions are found in informational units called _____.

polypeptides … genes

How are genes used by cells to build proteins?

The genes in DNA direct the synthesis of an RNA molecule, which is used to build a protein.

In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. What pairs with what?

In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.

A DNA nucleotide is composed of a __________.

deoxyribose sugar, which is bonded to a phosphate group and a nitrogenous base

When an RNA strand forms using DNA as a template, _____.

uracil pairs with adenine and cytosine pairs with guanine

DNA differs from RNA because DNA

contains thymine in place of uracil.

What is the complementary sequence to the DNA strand TCGATGG?

AGCTACC

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture _____.

DNA