Bio Chem Quiz 6

Nonpolar Amino Acid

Contain one amino group, one

carboxyl group, and a nonpolar side chain

Polar Neutral

Contain polar but neutral side

chains (6 amino acids) (alcohol)

Polar Acidic Amino Acids

Contain a carboxyl group as part of

the side chains (2 amino acids)

Polar Basic Amino Acids

Contain an amino group as part of

the side chain (3 amino acids)

Amino acids are organic compounds that contain a

_____ group and a _____ group and are found in

proteins as _____.

amino; carboxyl; alpha-amino acids

3 multiple choice options

Incomplete dietary proteins contain inadequate

amounts of:

one or more essential amino acids

3 multiple choice options

Name the following amino acids with correct designation for the enantiomer (chiral carbon is indicated by *)

A: L-isoleucine; B: D-cysteine; C: L-tyrosine

With few exceptions, the amino acids found in nature and in proteins are ___ isomers

L

3 multiple choice options

An amino acid with a positive charge on one atom

and a negative charge on another atom with an

overall charge of zero is known as a _____.

zwitterion

A _____ protein contains only amino acid residues,

and a _____ protein contains one or more non-amino

acids in the structures.

simple; conjugated

3 multiple choice options

The order in which amino acids are linked in a

protein is known as the _____ structure.

primary

The two most common types of secondary

structures of proteins are the _____ and the _____.

alpha helix; beta pleated sheet

3 multiple choice options

What type of attractive interaction, that contributes

to the tertiary structure of a protein, would be found

buried in a nonaqueous environment within the

protein?

hydrophobic interactions

3 multiple choice options

The structure of hemoglobin, with organization of its

alpha and beta subunits, is an example of what type

of protein structure?

quaternary

3 multiple choice options

Which of the following best describes what happens

to a small peptide when placed in an acid solution

and heated?

The small peptide undergoes hydrolysis to produce free amino acids.

3 multiple choice options

What is the consequence of protein denaturation?

all of the above

3 multiple choice options

What are enzymes?

specialized catalysts of biochemical reactions

2 multiple choice options

What is the difference between a simple enzyme and a

conjugated enzyme?

Simple enzymes are composed only of protein chains while conjugated enzymes have a nonprotein part in addition to a protein part.

A: transferase B. Lyase

What function does the substrate perform in an

enzyme-catalyzed reaction?

It is the substance upon which the enzyme acts.

3 multiple choice options

What is the area of an enzyme where catalysis of a substrate

occurs called?

active site

Which of the following statements is true about an

enzyme's absolute specificity?

Enzyme will catalyze a particular reaction for only one substrate.

What factors affect enzyme activity?

All of the above

3 multiple choice options

Identify the functions of carbohydrates in the human body.

All the above.

3 multiple choice options

Carbohydrates are classified as:

monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

3 multiple choice options

A- not; B- not; C- chiral; D-not

A carbohydrate molecule whose mirror image is not

superimposable is said to be a _____ molecule.

chiral

3 multiple choice options

What feature does a carbohydrate possess that

generates stereoisomerism?

presence of a chiral center

3 multiple choice options

What formula is used to show the two-dimensional structure of groups around chiral centers in a molecule?

Fischer projection

3 multiple choice options

How can you identify the D isomer of a carbohydrate

by looking at the Fischer projection formula?

The -OH group on the chiral carbon farthest from

the carbonyl group is pointing to the right.

3 multiple choice options

What is meant when it is said that carbohydrates are optically active compounds?

A solution of carbohydrate will rotate the plane of

polarized light.

3 multiple choice options

What structural feature distinguishes an aldose and a ketose?

An aldose possesses an aldehyde group, and a

ketose possesses a ketone group.

3 multiple choice options

Which monosaccharide is the most important from a human nutritional standpoint?

D-glucose

Monosaccharides in nature have cyclic forms because they can form:

internal hemiacetals that are stable.

Haworth projection formula for a monosaccharide is a

formula showing:

a two-dimensional notation that specifies the three-

dimensional structure of a cyclic monosaccharide

a. Ribose b. fructose c. galactose, glucose d. Fructose

What is the linkage that is formed when two monosaccharides react to form a disaccharide called?

alcohol group linkage

Which disaccharide is a nonreducing sugar?

sucrose

A _____ is a polysaccharide in which only one type of

monosaccharide monomer is present.

homopolysaccharide