Proteins

Question 1

What are proteins made up of?

Answer 1

Amino acids

Question 2

What is in all amino acids?

Answer 2

An amine group (2 hydrogen, 1 nitrogen)
One hydrogen bonded to a carbon in middle
An acid group
And an r group

Question 3

What is the R group in an amino acid?

Answer 3

Determines what the amino acid is and what it’s name is
Is different for all

Question 4

What elements do all amino acids contain?

Answer 4

Carbon, nitrogen, hydrogen and oxygen

Question 5

What extra element do some amino acids contain?

Answer 5

Sulfur

Question 6

What happens during the condensation of 2 amino acids?

Answer 6

The OH group in one (from acid group)
The H group in another (from amine group)
Release as water in condensation
And form a PEPTIDE BOND

Question 7

Dipeptide

Answer 7

2 amino acids joined together by a peptide bond from a condensation reaction

Question 8

Where in the body are dipeptides formed from condensation?

Answer 8

In ribosomes of cells to synthesise proteins

Question 9

Polypeptide chain

Answer 9

Repetition of the condensation of amino acids to form a long chain joined together by peptide bonds

Question 10

How can we reverse the formation of polypeptide chains?

Answer 10

Adding water molecules to hydrolyse it back down into amino acids

Question 11

Where does the hydrolysis of polypeptide chains occur?

Answer 11

In digestive system by protease to break the peptide chain into amino acids for digestion

Question 12

Are polypeptide chains proteins?

Answer 12

No, to become a protein the chain has to fold into a complex 3d shape/ join with other chains and therefore carry out its function

Question 13

Protein structure formation

Answer 13

Primary structure
Secondary structure
Tertiary structure
Quaternary structure

Question 14

Primary structure

Answer 14

The specific order or amino acids in a polypeptide chain
The order of them depending on the r group is critical in determining the secondary structure

Question 15

What determines the sequence of amino acids?

Answer 15

By the DNA sequence of the gene which encodes for that specific polypeptide chain

Question 16

Secondary structure

Answer 16

When the polypeptide chain twists and folds to perform specific functions and is held together by HYDROGEN BONDS
Has 2 distinct shapes which are regions that make up this structure

Question 17

2 secondary structure region shapes

Answer 17

Alpha helix
Beta pleated sheets

Question 18

How does the hydrogen bonding form between the secondary structure causing it to fold?

Answer 18

The O- atom in acid group is negatively charged
The H+ atom in amine group below from amine group is positively charged
So the chains layer on top of each other and hold the shapes

Question 19

How is the secondary structure dependent on the primary structure in terms of amino acids?

Answer 19

Because certain amino acids tend to be found in alpha helixes and others in beta pleated sheets
So these regions depend on the acids in this chain

Question 20

How is the secondary structure dependent on the primary structure in terms of polarity?

Answer 20

Because some amino acids are polar depending on the R group such as containing OH groups so they are hydrophilic and position themselves in the outside to interact with water
Whereas the inverse is true for hydrophobic amino acids which are hydrophobic so the folding is dependent on that

Question 21

Tertiary structure

Answer 21

When, after the secondary structure regions have formed the protein continues folding which is held together by R groups in amino acids

Question 22

Different bonds between the R groups in tertiary structure

Answer 22

Disulphide bridge
Ionic bonds
Hydrogen bonds
(Hydrophobic interactions)

Question 23

What does the quarterly structure apply to?

Answer 23

Only if the protein has 2 or more subunits

Question 24

Quaternary structure

Answer 24

When 2 or more polypeptide chains work together as a large molecule which is held together by bonds between the polypeptide chains

Question 25

Bonds between polypeptide chains in the quaternary structure

Answer 25

Same as between r groups in the tertiary structure:
Disulphide bridges
Ionic bonds
Hydrogen bonds

Question 26

Polypeptide chains in the quaternary structure

Answer 26

Known as subunits

Question 27

How does the quaternary structure depend on the tertiary structure?

Answer 27

The way individual subunits are arranged is the quaternary structure
And the way they arranged after folding is the tertiary structure so the way are bonded to each other is dependent on that