Chapter 9

Question 1

What part of a protein accounts for its many functions?

Answer 1

The several structures it has

Question 2

How many protein functions are there in?

Answer 2

1)enzymatic proteins= speed up chemical reactions(digestive enzyme trypsin)
2)storage protein =stores amino acids (ovalbumin provides amino acids to the growing embryo)
3)hormonal proteins= helps maintain homeostasis (insulin in blood sugar )
4) contractile motor protiens = involved in movement ( actin and myosin)
5)defensive proteins=helps protect from diseases (antibodies)
6)transport protiens =transports substances (permeases hemoglobin)
7) structural protiens = provide a role in support (collagen)
8) receptor protiens = mediate the response of a cell to a chemical stimulus (receptors on nerve cells)

Question 3

What are proteins?

Answer 3

Polymers made up of monomers called amino acids

Question 4

What are amino acids?

Answer 4

Are organic molecules possessing both carboxyl and amino groups
Differ in properties due to the differing side chains also known as R groups

Question 5

What is the basic structure of an amino acid?

Answer 5

Amino group (NH3)-C-(ATTACHED TO AN H AND R) AND A CARBOXYL GROUP (O-C=0)

Question 6

How many amino acids make up protiens ?

Answer 6

20 different amino acids

Question 7

What are the groups amino acids can be placed in?

Answer 7

Amino acids with polar chains(hydrophilic )= SER
Amino acids with nonpolar side chains (hydrophobic ) = ALA
Can be electrically charged

Question 8

What are acidic amino acids ?

Answer 8

Amino acids with the side chains that have a negative charge due to an ionized carboxyl group at cellular ph
Such as ASP

Question 9

What are basic amino acids?

Answer 9

Side chains that have a positive charge at cellular pH
Such as Lysine (Lys)

Question 10

How do amino acids join together to form a polymer ?

Answer 10

A dehydration reaction also known as a peptide bond

Question 11

How do peptide bonds form?

Answer 11

Forms when a carboxyl group from one amino acid reacts with the amino group of a second amino acid

Question 12

What is the difference between a polypeptide and a protein?

Answer 12

A polypeptide = refers to the immediate joining of amino acids by peptide bonds
Protein = a polypeptide or several that have folded into a functional conformation

Question 13

What are the characteristics of a protein?

Answer 13

Has biological activity
Is stable
Conformation is unique for each protein
Dependent on the sequence of amino acids in the polypeptide and how the side groups of each amino acids that interact with one another

Question 14

Who determined the amino acid sequence ?

Answer 14

Fredrick Sanger in 1955
Determined by chemical means

Question 15

What determines how a protein functions?

Answer 15

Specific conformation

Question 16

What is the primary structure of proteins?

Answer 16

The unique sequence of amino acids in a polypeptide and has amino acid subunits

Question 17

What is the secondary structure ?

Answer 17

The folding or coiling of the polypeptide into a repeating configuration

Question 18

What can the repeating conformation result in of a secondary protein structure?

Answer 18

In alpha helix or beta pleated sheet
These shapes come from the hydrogen bonding between the molecules of the backbone
This does not involve R -groups

Question 19

What is the tertiary structure?

Answer 19

Overall 3D shape of a polypeptide
This 3D shape come from interactions between the side chains (R group) of the amino acids
Has hydrogen bonds, Disulfide bridges and ionic bonds

Question 20

What is a quaternary structure

Answer 20

The overall protein structure that result from the aggregation of two or more polypeptide subunits
Such as collagen and hemoglobin

Question 21

What are the two main classes of protein structures?

Answer 21

Fibrous and globular

Question 22

What are the two main classes of protein structures?

Answer 22

Fibrous and globular