ch.5 mastering biology

A dehydration reaction (or condensation reaction) is the process in which _____.

water molecules are produced as a polymer is formed from monomers. Monomers are joined together in a reaction in which two molecules are covalently bonded to each other through the loss of a water molecule; this is called a condensation reaction or, specifically, a dehydration reaction.

The four main categories of large biological molecules present in living systems are _____.

proteins, nucleic acids, carbohydrates, and lipids. This choice identifies the four major classes of large biological molecules present in living systems

How many molecules of water are used to completely hydrolyze a polymer that is 11 monomers long?

10

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.

Plant cell walls consist mainly of _____.

cellulose

a polysaccharide that is a major component of the tough walls that enclose plant cells.

cellulose

What does the term insoluble fiber refer to on food packages?

cellulose

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

as a disaccharide

Starch and cellulose _____.

are polymers of glucose

Humans can digest starch but not cellulose because _____.

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

Select the statement that is incorrect…

All carbohydrates have the general formula Cn(H2O)n.This formula only applies to simple sugars, which are equal parts carbon and water. Complex sugars, which do not have this general formula, are also carbohydrates.

Select the type of carbohydrate that cannot be hydrolyzed, or split into smaller carbohydrates.

monosaccharides

A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a…..

carbohydrate

Lactose, the sugar in milk, is a ____________ , because it can be split into two monosaccharides

disaccharide

A carbohydrate that yields many monosaccharides when hydrolyzed is a…..

polysaccharide

The characteristic that all lipids have in common is that _____.

none of them dissolves in water. Almost all the covalent bonds in lipids are nonpolar, causing their solubility in water to be extremely low. Lipids are hydrophobic substances

Which of the following is the best explanation for why vegetable oil is a liquid at room temperature while animal fats are solid?

Vegetable oil has more double bonds than animal fats.

Some regions of a polypeptide may coil or fold back on themselves. This is called _____, and the coils or folds are held in place by _____.

secondary structure … hydrogen bonds.Secondary structure is the localized folding and/or coiling of the primary structure of a polypeptide. It results from hydrogen bonding between atoms of the polypeptide backbone.

What component of amino acid structure varies among different amino acids?

the components of the R-group

Which of the following is the strongest evidence that protein structure and function are correlated?

Denatured (unfolded) proteins do not function normally.

Which level of protein structure do the α-helix and the β-pleated sheet represent?

secondary

The tertiary structure of a protein is the _____.

unique three-dimensional shape of the fully folded polypeptide

What is the term used for a protein molecule that assists in the proper folding of other proteins?

chaperonin

At what level of protein structure do β-sheets of amino acids and α-helices, located at a distance from each other along the length of a polypeptide chain, come together to form a globular protein?

tertiary structure

What level of protein structure describes an amino acid sequence such as Ala-Gly-Ser-Val-Glu-Glu-Glu-Ala-His…?

primary structure

At what level of protein structure do the α and β protein subunits come together to catalyze the hydrolysis reaction?

quaternary structure

At what level of protein structure do the chains of amino acids fold into an α-helical structure?

secondary structure

primary structure

a peptide or protein is the linear sequence of its amino acid structural units, and partly comprises its overall biomolecular structure.

secondary structure

general three-dimensional form of local segments of proteins and can be formally defined by the pattern of hydrogen bonds of the protein (such as alpha helices and beta sheets) that are observed in an atomic-resolution structure.

tertiary structure

have a single polypeptide chain "backbone" with one or more protein

Quaternary structure

the arrangement of multiple folded protein or coiling protein molecules in a multi-subunit complex

The flow of genetic information in a cell goes from _____.

DNA to RNA to protein.The information in DNA is transcribed into RNA and then translated into protein

The building blocks or monomers of nucleic acid molecules are called _____.

nucleotides and A nucleotide is a nucleic acid monomer consisting of a nitrogen base, a pentose sugar, and a phosphate group. Nucleotides joined together by covalent bonds called phosphodiester linkages form nucleic acid molecules.

Nucleic acids are polymers made up of which of the following monomers?

nucleotides

Which of the following includes all of the pyrimidines found in RNA and DNA?

cytosine, uracil, and thymine

One of the primary functions of RNA molecules is to _____.

function in the synthesis of proteins

Which of the following statements best summarizes the differences between DNA and RNA?

DNA nucleotides contain a different sugar than RNA nucleotides.

What structural difference accounts for the functional differences between starch and cellulose?

Starch and cellulose differ in the glycosidic linkages between their glucose monomers.Both starch and cellulose are glucose polymers, but the glycosidic linkages in these two polymers differ. Glucose can have two slightly different ring structures. When glucose forms a ring, the hydroxyl group attached to the number 1 carbon is positioned either below (alpha) or above (beta) the plane of the ring. In starch, all the glucose monomers are in the alpha configuration. In cellulose, all the glucose monomers are in the beta configuration. As a result, every other glucose monomer is "upside down" with respect to its neighbors. The differing glycosidic linkages in starch and cellulose give the two molecules distinct three-dimensional shapes, leading to key functional differences.

Which level(s) of protein structure may be stabilized by covalent bonds?

Primary, tertiary and quaternary levels of protein structure.The primary structure of a protein is the specific linear sequence of amino acids forming the protein. The amino acids are joined by covalent peptide bonds. Tertiary structure, producing the unique structure of a protein, is stabilized by interactions among the R groups on each amino acid in the protein. Tertiary structure may be stabilized by covalent bonds, called disulfide bridges, that form between the sulfhydryl groups (SH) of two cysteine monomers. Tertiary structure may also be stabilized by weaker interactions, including hydrogen bonds between polar and/or charged areas, ionic bonds between charged R groups, and hydrophobic interactions and van der Waals interactions among hydrophobic R groups. Many globular proteins are made up of several polypeptide chains called subunits stuck to each other by a variety of attractive forces but rarely by covalent bonds. Protein chemists describe this as quaternary structure.

Which level of protein structure is characteristic of some, but not all, proteins?

Quaternary level of protein structure. Quaternary structure results from the aggregation of two or more polypeptide subunits, and not all proteins are composed of more than one polypeptide.

Which molecule is a nucleotide?

ATP.A nucleotide consists of three parts: a nitrogenous base, a pentose sugar, and one or more phosphate groups. ATP consists of a nitrogenous base (adenine), a pentose sugar, and three phosphate groups

Which feature of large biological molecules explains their great diversity?

The many ways that monomers of each class of biological molecule can be combined into polymers.Biological molecules belong to four main classes, and are constructed from only 40 to 50 common monomers (and a few rare ones) made of only a few of the 92 naturally occurring elements. The diversity of biological molecules is due to differences in the arrangements of the monomers in each molecule.