Biology-Week 3 Assignment 4
Individual polypeptides within a protein are referred to as which of the following?
Subunits
Protein denaturation may be caused by an increase in which of the following?
Temperature Ionic concentration pH
The tertiary structure of a protein is determined primarily by interactions involving which of the following?
The R groups of the amino acids
What is the primary structure of a protein?
The amino acid sequence of the polypeptides.
Regarding polypeptides, the two basic types of_______structure are alpha____and beta-pleated sheet.
secondary helix or helices
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
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.
Which of the following statements about the relationship between enzymes and environmental conditions are true?
Changing environmental conditions may alter the activity of enzymes. Changing environmental conditions may alter the structure of enzymes. The optimum conditions for enzyme activity are usually similar to the conditions where the enzyme normally functions.
Which of the following determines the function of a protein molecule?
Its shape
What type of bond forms between two amino acids during dehydration synthesis?
Peptide bond
Proteins are made up of one or more unbranched chains of
amino acids
When two amino acids are linked together, a peptide bond is formed between the_____group of one and the____group of the other.
amino, positive amino, or NH3+ carboxyl, negative carboxyl, or COO-
Diseases caused by the improper folding of proteins may be due to deficiencies in______proteins.
chaperone
A protein with quaternary structure
contains two or more polypeptide chains.
The structure of_____is usually discussed in terms of a hierarchy of 4 levels.
proteins
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 type of interaction involves the formation of a covalent bond between two different amino acid side chains?
Disulfide bridge
Which of the following best describes the relationship between temperature and enzyme activity?
Each enzyme has an optimum temperature where it functions best.
True or false: Protein structure is usually not affected by changes in the temperature, pH, or ionic concentration of the surrounding solution.
False
A protein is initially driven into its tertiary structure by what type of interactions?
Hydrophobic exclusion
Which of the following interactions help determine a protein's tertiary structure?
Hydrophobic exclusion Ionic bonds Disulfide bridges Hydrogen bonds
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 level(s) of protein organization involve(s) two or more polypeptide chains?
Quaternary
A protein's final structure can include either which of the following? regions shaped like an α-helix or regions shaped like a β-pleated sheet but not both.
Regions shaped like an α-helix and regions shaped like a β-pleated sheet.
Which characteristic of a protein determines its function?
Shape
What are the three major structural components of an amino acid?
Side chain (R) Amino group Carboxyl group
Which describes denatured proteins?
They are usually inactive.
Of the following list, choose the functions of proteins in living cells.
They catalyze chemical reactions. They play a key role in moving materials within cells. They transport oxygen in the blood of vertebrates. They help the body recognize and destroy foreign microbes and cancer cells.
Which of the following are functions of proteins?
They play a key role in the contraction of muscles. They transport ions and molecules across cell membranes. They provide structural support for many animal tissues. They catalyze chemical reactions.
Which of the following are functions of proteins?
They transport ions and molecules across cell membranes. They provide structural support for many animal tissues. They play a key role in the contraction of muscles. They catalyze chemical reactions.
Changes in a protein's shape can alter its ability to function or even cause it to become biologically
inactive
The covalent bond that joins two amino acids is called a_____bond.
peptide
The amino acid sequence of its polypeptides is called the_____structure of a protein.
primary
primary secondary tertiary quaternary
the linear sequence of amino acids repetitive folding patterns such as alpha helix and beta pleated sheet the overall 3-D shape of each polypeptide how two or more polypeptides interact to form a protein
What are the two basic types of secondary structure in proteins?
α- helix and β-pleated sheet