Module 2:Biological Molecules

Question 1

What monomer makes up proteins?
What type of molecule is a protein?

Answer 1

amino acids
a polymer molecule

Question 2

How many different naturally occuring AA are there ?
How many are essential ?
Can essential amino acids be synthesised in the body?

Answer 2

there are 20 , 9 of them are essential

no , but non essential ones can

Question 3

What elements can be present in proteins?

Answer 3

carbon , hydrogen , oxygen , nitrogen
sometimes sulphur and phosphorus

Question 4

Draw the general structure of an AA
(reference the amine , carboxyl and R group

Question 5

Describe how AA join together in condensation reactions
2 points
(include the name of the bond formed)

Answer 5

1 molecule of water is removed using the OH of the carboxyl group of 1 amino acid and the H of another amino acids amine group

this forms a peptide bond

Question 6

What is a polypeptide?

Answer 6

many amino acids joined together

Question 7

Name and explain the 4 main biological roles of proteins

Answer 7

structural-main component of bodily tissues such as muscles , skin , ligaments etc

catalytic-all enzymes are proteins

signalling-many hormones and receptors are proteins

immunological-all antibodies are proteins

Question 8

What are the 4 different levels of protein structure?

Answer 8

primary
secondary
tertiary
quaternary

Question 9

Define what is meant by the primary structure of a protein

What does this level of structure define?

Answer 9

the order and number of amino acids in the polypeptide chain

the shape of the protein , hence its function

Question 10

Define what is meant by the secondary structure of a protein

Answer 10

the formation of H bonds between amino acids which causes the protein to coil into a alpha helix structure or a beta pleated sheet structure

Question 11

Define what is meant by the tertiary structure of a protein

Name the 4 types of bonding that occurs at this level

Answer 11

the further folding/coiling of the protein chains due to further bonding

H bonds
ionic bonds
disulfide bridges
hydrophobic interactions

Question 12

Define what is meant by the quarternary structure of a protein

Answer 12

occurs when there are several polypeptide chains

refers to how these chains are arranged together

Question 13

What is an ion?
What is the main difference between organic and inorganic ions?

Answer 13

a particle with an electrical charge

organic-contain carbon
inorganic-don’t contain carbon

Question 14

Name the 4 main ions

Answer 14

iron ions
sodium ions
hydrogen ions
phosphate ions

Question 15

Describe the role(s) of iron ions and hydrogen ions in the body

Answer 15

iron- they are a component of haemoglobin and are mainly found in RBCs

hydrogen-they are important for synthesis of ATP during respiration and determine the pH of substances

Question 16

Describe the role(s) of sodium ions and phosphate ions in the body

Answer 16

sodium-they are involved in co-transport of glucose and amino acids and are also important for communication between neurons

phosphate-they are a component of DNA , RNA and ATP