Proteins

Question 1

Describe the formation of an Amino Acid

Answer 1

he side group consisting of RCH

An amino group consisting of NH2 which is bonded to the left of the C in the side group

A carboxyl group consisting of COOH which is bonded to the right side of the C in the side group

Question 2

How many naturally occurring AAs are there and what’s the difference between them

Answer 2

20

They all have different side groups- The R changes

Question 3

How are di/polypeptides formed

Answer 3

A condensation reaction between the carboxyl group of one Amino Acid and the amine group of another

Removes a water molecule and joined by a peptide bond

Question 4

What bond joins two amino acids

Answer 4

Peptide bond

Question 5

Describe the primary structure of protein

Answer 5

The sequence or order of AAs which make up the polypeptides of a protein

Linear chain of AAs joined by peptide bond and each has a different order of AAs

Question 6

Describe the secondary structure of protein

Answer 6

The particular folding of a chain of AAs in the polypeptide of a protein

Question 7

What are the two types of folds seen in a secondary structure of protein

Answer 7

helical and sheets

Question 8

What causes folding in a protein’s secondary structure to be helical

Answer 8

H-bonding forms between -COOH and -NH2 in an alpha glucose

Question 9

What causes folding in a protein’s secondary structure to be sheets

Answer 9

H-bonding forms between -COOH and -NH2 in a beta glucose

Question 10

Describe the tertiary structure of protein

Answer 10

The particular folding of a whole polypeptide chain as determined by amino acids that make up the polypeptide

Bonding between the R-groups

Question 11

What times of bonds can form in the tertiary structure of protein and where

Answer 11

Hydrogen bond between O-H

Ionic bond between NH3-O

Disulphide bridge between S-S

Question 12

Describe the quaternary structure of a protein

Answer 12

2 or more polypeptide chains linked together in a precise structure and sometimes associated with a prosthetic group

Question 13

Describe how the structure of a protein depends on the AAs it contains

Answer 13

Relative positions of AAs
The primary structure is order of AAs
The secondary structure is formed by Hydrogen bonding between AAs
Tertiary structure is formed by bonds between R groups

Quaternary structure contains more than 1 polypeptide chain and structure is formed by bonds between polypeptide

Question 14

Describe how AAs join to form a polypeptide so NH2 is at one end and COOH is at the other end

Answer 14

one NH2 group joins a COOH group forming a peptide bond

there is a free NH2 at one end and a free COOH group at the other

Question 15

Describe a food test to confirm the presence of protein in a solution

Answer 15

Add biuret reagant to get a positive result of lilac

Question 16

Describe ways that Dipeptides are similar

Answer 16

Amine group at each end
Carboxyl group at each end
Two R groups
All contain C H N and O

Question 17

Describe ways that dipeptides differ

Answer 17

Different R groups