biological molecules: structure of proteins

Question 1

amino acid structure

Answer 1

amine group
r group
carboxyl group

Question 2

non essential amino acids

Answer 2

our liver can make them from other amino acids

Question 3

essential amino acids

Answer 3

needed in our diets

Question 4

conditionally essential amino acids

Answer 4

only needed by infants and growing children

Question 5

synthesis of peptides

Answer 5

when a hydroxyl in the carboxyl group of one amino acid reacts with the hydrogen in the amine group of another amino acid
a peptide bond is formed by a condensation reaction producing water
resulting in a dipeptide

Question 6

how is a polypeptide bond reaction catalysed

Answer 6

by the enzyme peptidyl transferase present in ribosomes the site of protein synthesis

Question 7

primary structue of a protein

Answer 7

describes the sequence and composition
only peptide bonds

Question 8

sechondary structure of a protein

Answer 8

describes how primary structure folds in on itself
only hydrogen bonds
produces alpha felix and beta pleated sheets

Question 9

tertiary structure of a protein

Answer 9

describes how the sechondary structure further folds in on itself
held by bonds between r groups
4 different types of bonds

Question 10

the four different types of bonds in tertiary and quaternary structure of proteins

Answer 10

hydrogen bonds - weakest and can be broken by an increase in temperature
ionic bonds produces alpha- between positive and negative chargers can be broken by an PH change
disulphide bridge - between 2 cystenises and is the strongest bond
hydrophobic interaction - relatively weak between non polar molecules

Question 11

quaternary structure of a protein

Answer 11

found in proteins containing more than one polypeptide chain
describes how different polypeptide chains can be arranged together
can be different or identical
4 different bonds