Proteins

Question 1

What is an amino acid

Answer 1

The monomers from which proteins are made

Question 2

In an amino acid what does the NH2 represent

Answer 2

The amine group

Question 3

In an amino acid what does the COOH represent

Answer 3

A carboxyl group

Question 4

In an amino acid what does the R represent

Answer 4

The side chain

Question 5

What changes in an amino acid

Answer 5

The side group (R group )

Question 6

What does the condensation between 2 amino acids produce

Answer 6

A peptide bond

Question 7

A dipeptide formed by condensation what

Answer 7

Two amino acids

Question 8

A polypeptide is formed by condensing what

Answer 8

Many amino acids

Question 9

What does an enzyme do

Answer 9

Lowers the activation energy for the reaction it catalyses

Question 10

What do the properties of enzymes relate to

Answer 10

Tertiary structure of its active site
It ability to combine with a complementary substrate to form an enzyme- substrate complex

Question 11

What are all proteins monomer

Answer 11

Amino acids

Question 12

How many different amino acids

Answer 12

20

Question 13

2 groups in an amino acid ( general)

Answer 13

Amine group
Carboxylic acid group

Question 14

What chnages in the structure of the amino acid

Answer 14

The R group

Question 15

What are the 4 main elements in an amino acid

Answer 15

Nitrogen
Hydrogen
Carbon
Oxygen

Question 16

What is the bond between 2 amino acids called

Answer 16

A peptide bond

Question 17

What type of reaction is 2 amino acids joining together and why

Answer 17

Condensation reaction
Molecule of water is lost

Question 18

What is the name for 2 amino acids bonded together

Answer 18

Dipeptide

Question 19

Where does protein synthesis take place

Answer 19

Ribosome

Question 20

What are 3 or more amnio acids joined together called

Answer 20

A polypeptide

Question 21

Hydrophobic =
Hydrophilic =. (Hint charge)

Answer 21

Non-polar
Polar

Question 22

Difference between protein and polypeptide

Answer 22

Polypeptide has to fold into a complex 3D shape
Once folded and carrying out it’s function it is a protein

Question 23

Level 1 of protein structure + importance

Answer 23

Primary Structure
- specific order of amino acids in a polypeptide
Helps determine 3D shape of molecule - function

Question 24

How is the structure of a protein determined

Answer 24

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

Question 25

Level 2 protein structure Groups in a polypeptide chain + charges

Answer 25

C=0 and N-H C=0 ---> - N-H ---> + Charges attract to form hydrogen bonds Causes twists and folds

Question 26

Level 2 protein structure

Answer 26

Is the overall 3D shape of protein Areas of beta pleat sheet Areas of alpha helix

Question 27

Level 4 protein structure

Answer 27

Subunit - multiple polypeptides Only applies to proteins with 2 subunits Prosthetic groups

Question 28

What is a subunit protein

Answer 28

Made up of multiple polypeptide chains

Question 29

What is the prosthetic group + what they do

Answer 29

Non- protein molecules forming part of the structure of a protein Help protein carry out its role

Question 30

What are proteins with prosthetic groups called

Answer 30

Conjugated proteins

Question 31

What is an uncharged R group called

Answer 31

Non-polar amino acid

Question 32

Are non-polar amino acids attracted to water

Answer 32

No

Question 33

What is it called when a polar amino acids is not attracted to water

Answer 33

Hydrophobic

Question 34

Explain a hydrophobic interaction

Answer 34

Amino acids with hydrophobic R groups cluster together and exclude water molecules

Question 35

Where are hydrophobic and hydrophilic amino acids found

Answer 35

Hydrophobic in the centre of proteins away from water Hydrophilic on the surface of proteins where they can interact with water molecules

Question 36

Where is an iconic bond found (proteins)

Answer 36

Between amino acids with charged R groups

Question 37

How are ionic bonds in proteins broken

Answer 37

By changed in PH

Question 38

What is a disulphide bond

Answer 38

When the Sulphur atoms between two cysteine molecules form a covalent bond

Question 39

What are the two types of secondary structure

Answer 39

Alpha helix’s Beta pleated sheets

Question 40

What are the two groups of proteins

Answer 40

Globular Fibrous

Question 41

Globular proteins are soluble/insoluble + why

Answer 41

Soluble They have hydrophilic amino acids on their surface ( hydrophobic are in centre)

Question 42

Are Fibrous proteins soluble / insoluble + why

Answer 42

Insoluble Hydrophobic R groups

Question 43

Which test is used for proteins

Answer 43

Biuret

Question 44

How to carry out biuret test

Answer 44

Add sodium hydroxide - to make alkaline Add copper (ll) sulfate solution Negative - blue Positive - purple

Question 45

Amylase, protease and lipase do what to the thing they break chemical process

Answer 45

Hydrolyses

Question 46

Test for proteins

Answer 46

Add Biuret Positive results purple

Question 47

Two ways in which all dipeptides are similar

Answer 47

Amine group Carboxylic group

Question 48

One way in which dipeptides are different

Answer 48

Different R groups

Question 49

What bonds are present in Tertiary structure of amino acid

Answer 49

Hydrogen Disulphide bridges ( only between cysteine) Ionic

Question 50

Where is lactose attached to a polypeptide to form a glycoprotein

Answer 50

Golgi apparatus

Question 51

Level 3 protein structure

Answer 51

The interactions between the R groups - hydrogen bonds (between R groups) - disulphide bridges - ionic bonds

Question 52

What interactions occur between non-polar R groups

Answer 52

Weak hydrophobic interactions (non polar = hydrophobic