Unit 2(c) Proteins

Question 1

What is the chemical formula for ammonia?

Answer 1

NH3

Question 2

What are some properties of ammonia?

Answer 2

• Ammonia is very soluble in water

* It dissolves to produce an alkaline solution (it is the only non metal gas that does this)

Question 3

What is the general formula for amines?

Answer 3

CnH2n+1NH2

Question 4

What functional group is present in amines?

Answer 4

Amino group - NH2

Question 5

What two functional groups are present in amino acids?

Answer 5

Amino group and carboxyl group

Question 6

What is the term for amino acids when the animo group and the carboxyl group are on the same carbon?

Answer 6

Alpha-amino acids

Question 7

What are essential amino acids?

Answer 7

Amino acids which cannot be synthesised in the body by altering other amino acids. They must be present in the human diet

Question 8

What are some sources of amino acids?

Answer 8

Meats and animal produce

Question 9

What are proteins made of?

Answer 9

Amino acid monomers

Question 10

How are proteins formed?

Answer 10

Condensation polymerisation - water eliminated

Question 11

What is the name for the link between and amine group and an acid group?

Answer 11

Peptide link (CONH)

Question 12

How are proteins broken down during digestion?

Answer 12

Hydrolysis

Question 13

What process is used to analyse the products of hydrolysed proteins?

Answer 13

Chromatography

Question 14

What is the formula for the Rf value?

Answer 14

Rf = distance run by spot / distance run by solvent

Question 15

What are the two types of proteins?

Answer 15

Fibrous and globular

Question 16

What are fibrous proteins?

Answer 16

They are long and thin because of the long polyamide chains

Question 17

Why do fibrous proteins take their structure?

Answer 17

Intermolecular hydrogen bonding

Question 18

What fibrous protein structure is observed if the hydrogen bonds are within the same chain?

Answer 18

Spiral/Helix structure

Question 19

What fibrous protein structure is observed if hydrogen bonding occurs between different chains?

Answer 19

Sheet like structure

Question 20

Give some examples of fibrous proteins

Answer 20

Keratins, elastins, collagens

Question 21

What are globular proteins

Answer 21

They are spiral chain proteins folded into compact units

Question 22

Are globular proteins soluble or insoluble in water?

Answer 22

Soluble, so they can move around in the bloodstream

Question 23

Give some examples of globular proteins

Answer 23

Haemoglobin, insulin, enzymes, casein, and many hormones

Question 24

What are enzymes?

Answer 24

Biological catalysts made of proteins.

Question 25

Why are enzymes specific?

Answer 25

They only work on one substrate - 'lock and key'

Question 26

What happens when enzymes are denatured?

Answer 26

Hydrogen bonds are broken, active site changes shape

Question 27

What happens to proteins during cooking?

Answer 27

Intermolecular bonds are broken, alters texture of a food