Proteins-bonding and structure

Question 1

What’s the primary structure of a protein

Answer 1

The sequence of amino acids

Question 2

How many amino acids are there

Answer 2

20

Question 3

How many possible combinations of amino acids does a polypeptide chain with 4 amino acids have

Answer 3

20^4 = 160,000

Question 4

Primary structure: Draw 4 amino acids bonded together

Question 5

What’s secondary structure

Answer 5

The initial folding of the polypeptide chain due to H bonds(search up a diagram) which form between nearby amino acids in the chain, making it coil into one of two types of secondary structures

Question 6

What secondary structure do some primary structures “coil into”

Answer 6

Alpha helix, with 36 amino acids per 10 turns of the helix

Question 7

How is the alpha helix held together

Answer 7

By H bonds between NH group of one amino acid and the -CO group of another 4 places ahead of it in the chain(search up a diagram)

Question 8

What secondary structure do some primary structures “fold into”

Answer 8

Beta pleated sheet

Question 9

What makes alpha helix and beta pleated sheet stable structures at optimal ph and temp even tho H bonds are weak

Answer 9

They have many H bonds

Question 10

Does one polypeptide chain only have one type of secondary structure

Answer 10

No , a single polypeptide chain can have multiple secondary structures

Question 11

Search up a diagram of a beta pleated sheet of a polypeptide chain

Question 12

What is the tertiary structure of a protein

Answer 12

The folding of the secondary protein structure into a specific 3D shape which is held together by bonding and interactions between different R groups.

Question 13

What bonds start to form in tertiary structure

Answer 13

More
bonds(ionic, covalent,hy drophillic and hydrophobic interactions)start to form between different parts of the chain, hydrogen bonds also form but they start to form in secondary structure.

Question 14

What’s proteins adopt a supercoiled tertiary structure

Answer 14

Fibrous proteins

Question 15

What proteins adopt a spherical shaped tertiary structure

Answer 15

Globular proteins

Question 16

Draw a diagram of the tertiary structure of a globular protein

Question 17

How is the tertiary structure of a protein held together

Answer 17

by bonding between different R groups of different amino acids

Question 18

What is the final 3D structure of a protein made from only one polypeptide chain

Answer 18

The tertiary structure

Question 19

What is the quaternary structure of a protein

Answer 19

The 3D structure which is composed of two or more tertiary subunits(polypeptide chains), it has the same bonds between R groups of different amino acidsionic bonds, covalent ect).

Question 20

Do all proteins have a quaternary structure

Answer 20

No

Question 21

What is the final 3D structure of a protein made from 2 or more polypeptide chains?

Answer 21

Quaternary structure

Question 22

Draw a table for the different types of bonding in each level of protein structure

Question 23

What does quaternary structure describe

Answer 23

The association between two or more polypeptide chains

Question 24

What is the difference between secondary ,tertiary and quaternary protein structure ?

Answer 24

Secondary is primary held together by H bonds but tertiary and quaternary are held together by H bonds and many others

Question 25

See p68 for diagrams of hydrogen , ionic and disulphide bonds between two polypeptide chains

Question 26

How do hydrogen bonds form between two polypeptide chains(quaternary) or one polypeptide chain ( tertiary)

Answer 26

They may form between the amino group of one amino acid and the carboxyl group of another.They may also form between the polar areas of R groups on different amino acids.

Question 27

How do ionic bonds form between two polypeptide chains ( quaternary ) or one polypeptide chain ( tertiary )

Answer 27

They can form between the carboxyl group and amino groups that are apart of R groups of two different amino acids , these ionise into COO- and NH3+ and an ionic bond forms between

Question 28

What does it mean when a carboxyl and amino group is part of an R group

Answer 28

The R group can include functional groups like an for example lysine contains an amino group in its R group

Question 29

How are disulphide bridges formed between two polypeptide chains(quaternary) or one polypeptide chain ( tertiary)

Answer 29

The r group of the amino acid cysteine contains S , disulphide bridges form between the R groups of two cysteines

Question 30

What are disulphide bridges

Answer 30

Strong Covalent bonds

Question 31

How do hydrophilic and hydrophobic interactions occur between two polypeptide chains (quaternary) or in one polypeptide (tertiary)

Question 32

Draw a diagram of the quaternary structure of a globular protein

Question 33

does one polypeptide chain=one beta pleated sheet/one alpha helices?

Answer 33

No, a single polypeptide chain can form multiple alpha helices and beta pleated sheets and a single polypeptide chain can also just form alpha helices in some cases because the secondary structure of a protein depends on interactions between amino acids.