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Flashcards in Ch. 4 Deck (47)
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1

How many different amino acids are used in making proteins?

20

2

Which parts of amino acids are involved in peptide bonds?

The amino group on one amino acid and the carboxyl group on the other

3

Which part of an amino acid gives it its unique properties?

The side chain

4

In a folded protein, the nonpolar (hydrophobic) amino acids tend to be:

tucked away inside the protein.

5

What provides the information necessary to specify the three-dimensional shape of a protein?

The protein’s amino acid sequence

6

The biological activity of a protein is determined by its:

Amino Acid Sequence

7

A protein can be unfolded by a process called:

denaturation

8

What hydrogen bonds have been found to stabilize a polypeptide’s folded shape?

-Hydrogen bonds between side chain atoms
-Hydrogen bonds between backbone atoms and side chain atoms
-Hydrogen bonds between backbone atoms

9

What is the best type of model for visualizing the surface of a protein?

The space-filling model

10

Why are /alpha helices and /beta sheets common folding patterns in polypeptides?

Amino acid side chains are not involved in forming the hydrogen bonds, allowing many different sequences to adopt these folding patterns.

11

Those portions of a transmembrane protein that cross the lipid bilayer usually consist of which structures?

An /alpha helix with mostly nonpolar side chains

12

The two types of /beta sheets are:

parallel /beta sheets and antiparallel /beta sheets.

13

What does the primary structure of a protein refer to?

The amino acid sequence of the protein

14

What is the name for a modular unit from which many larger proteins are made?

Protein domain

15

.In a protein, intrinsically disordered sequences:

A. have a variety of important functions.
B. can wrap and bend around target proteins.
C. are ideal substrates for the addition of chemical groups that can modify protein behavior.

16

Theoretically, a vast number of different proteins can be assembled from 20 different amino acids. How many polypeptide chains are possible that are 10 amino acids long?

20^10

17

What are protein families?

Evolutionarily related proteins that are similar in amino acid sequence and three-dimensional conformation.

18

What is the definition of a binding site on a protein?

Any region that interacts with another molecule through sets of noncovalent bonds.

19

Actin filaments, microtubules, and the spherical shells of some virus particles are all:

structures built from sets of identical proteins.

20

T or F: Enzymes are examples of fibrous proteins.

False

21

Which of the following is NOT formed by fibrous proteins?
A. Actin filaments
B. Extracellular matrix
C. Collagen
D. Elastin

Actin filaments

22

Which of the following is formed by fibrous proteins?
A. Actin filaments
B. Extracellular matrix
C. Collagen
D. Elastin

Extracellular Matrix
Collagen
Elastin

23

The most common covalent cross-links in proteins are sulfur-sulfur bonds that form between two amino acids with -SH (thiol) groups as side chains. Which amino acid has this side chain?

Cysteine

24

The ability of a protein to bind selectively and with high affinity to specific molecules is due to which types of bonds?
A. Weak, noncovalent bonds
B. Strong, covalent bonds

Weak, noncovalent bonds

25

How many identical binding sites exist on an antibody?

2

26

What determines the specificity of an antibody for its antigen?

The amino acid loops in its variable domain

27

T or F: Enzymes that catalyze two or more chemical reactions link metabolic pathways in cells.

False

28

Which of the following is NOT true about enzymes:
A. They can bring reactants together in the proper orientation for chemistry to occur.
B. They can change the shape of substrates to increase the rate of a particular reaction.
C. They require an input of energy from ATP for activation.
D. They can form covalent bonds with their substrates.

They require an input of energy from ATP for activation.

29

All enzymes:
A. boost the activation energy of a reaction.
B. eliminate the activation energy of a reaction.
C. decrease the activation energy of a reaction.
D. do not alter the activation energy of a reaction.

do not alter the activation energy of a reaction.

30

T or F: Most drugs work by inhibiting the functions of enzymes.

True