Protiens

What is the primary structure of a protein?

The amino acid sequence of the polypeptides.

Which part of an amino acid is always acidic?

The carboxyl group

What are the two basic types of secondary structure in proteins?

α- helix and β-pleated sheet

What are the two major functional groups found in an amino acid, which allow it to form a peptide bond with another amino acid?

Carboxyl group and Amino Group

Diseases caused by the improper folding of proteins may be due to deficiencies in ____________ proteins.

Chaperone

Changes in a protein's environment can cause the protein to unfold and lose its shape in a process called which of the following?

Denaturation

Which of the following best describes the relationship between temperature and enzyme activity?

Each enzyme has an optimum temperature where it functions best.

Why do cells increase the production of many chaperone proteins when they are exposed to high temperatures?

High temperatures cause proteins to unfold and more chaperones are needed to help them refold correctly.

Which type of interaction plays a key role in determining both the secondary and tertiary structure of a protein?

Hydrogen bonds

What are the three major structural components of an amino acid?

Carboxyl group Amino group Side chain (R)

Select the characteristics of chaperone proteins.

-Cells increase the production of many chaperone proteins when they are exposed to high temperatures -They are used both to accomplish the original folding of proteins and to restore the structure of incorrectly folded proteins. -They have been found in virtually every organism that has been examined.

Which of the following statements about the relationship between enzymes and environmental conditions are true?

-Changing environmental conditions may alter the structure of enzymes. -Changing environmental conditions may alter the activity of enzymes. -The optimum conditions for enzyme activity are usually similar to the conditions where the enzyme normally functions.

Match the level of protein structure with the correct description. Primary Secondary Tertiary Quaternary

-Sequence of amino acids -α-helices and β-sheets -Three-dimensional folding of a single polypeptide -Interactions between 2 or more polypeptides to form a protein

Match the level of protein organization with the proper description. -Primary -Secondary -Tertiary -Quaternary

-The linear sequence of amino acids -Repetitive folding patterns such as alpha helix -The overall 3-D shape of each polypeptide -How two or more polypeptides interact to form a protein

Which of the following are functions of proteins?

-They catalyze chemical reactions. -They transport ions and molecules across cell membranes. -They play a key role in the contraction of muscles. -They provide structural support for many animal tissues.

Of the following list, choose the functions of proteins in living cells.

-They transport oxygen in the blood of vertebrates. -They play a key role in moving materials within the cell. -They help the body recognize and destroy foreign microbes and cancer cells. -They catalyze chemical reactions.

How many polypeptides are present in a protein whose highest level of structure is tertiary structure?

1 polypeptide only

Proteins are polymers made up of how many different amino acids?

20

The structure of proteins is usually discussed in terms of a hierarchy of how many levels?

4 levels (Primary, secondary, tertiary, and quaternary)

Which of the following accurately describes the chemical structure of a typical amino acid found in a protein?

A central carbon atom is bound to an amino group, carboxyl group, a side chain, and a hydrogen atom.

Select the disease type that could result from a deficiency in chaperone proteins.

A disease caused by improper folding of proteins

What are the building blocks of proteins?

Amino acids

The two major functional groups found in all amino acids are the basic __________ group and the acidic ___________ group.

Amino, Carboxyl

If the interactions that maintain the 3-dimensional shape of a protein are disrupted so that the polypeptide chains completely unfold, how is this protein described?

It is denatured.

Which of the following determines the function of a protein molecule?

It's shape.

You are studying a protein and notice that it contains two regions made of beta-sheets connected by an alpha-helix. This type of recurring structure that can be found in proteins with very different functions is called a

Motif

In general, where are nonpolar and polar amino acids found in a folded protein?

Non-polar- Interior Polar- Exterior

The covalent bond that joins two amino acids is called a ____________ bond.

Peptide

What type of bond forms between two amino acids during dehydration synthesis?

Peptide bond

The amino acid sequence of its polypeptides is called the _________ structure of a protein.

Primary

The _________, __________, and _______ structural levels of a protein describe a protein with a single polypeptide chain.

Primary, Secondary, and Tertiary

The structure of ___________ is usually discussed in terms of a hierarchy of 4 levels.

Proteins

A protein that is composed of multiple polypeptides is said to have __________ level of protein structure.

Quaternary

Which of the following level(s) of protein organization involve(s) two or more polypeptide chains?

Quaternary

Regarding polypeptides, the two basic types of _____________ structure are alpha _________ and beta-pleated sheet.

Secondary, Helix

Hydrogen bonds between the amino and carboxyl groups of the polypeptide backbone help determine protein _____________ structure while hydrogen bonds between the amino acid side chains help determine protein ___________ structure.

Secondary, Tertiary

Which characteristic of a protein determines its function?

Shape

The 20 common amino acid are classified into five chemical classes based on which of the following?

Their R groups

The unique properties of the 20 common amino acid are determined by which of the following?

Their R groups

How can scientists use protein motifs?

They can be used to predict the function of a protein

Select amino acids that are most likely to be found in the interior of a protein.

Valine, Phenylalanine, Leucine