amino acids - the basics

Question 1

what does the general structure of an amino acid look like?

Answer 1

see iphone

Question 2

what is the name of the group on the left?
and the group on the right?

Answer 2

• amine
• carboxyl

Question 3

what does the r group do (3)

Answer 3

• determines how the amino acid interacts
• determines how the amino acid bonds with OTHER amino acids in the polypeptide
• determines the properties of the polypeptide

Question 4

what is a protein?

Answer 4

• polymers made up of monomer amino acids

Question 5

what does a peptide bond do? (as in job)

Answer 5

• holds the amino acids in a chain in the polypeptide

Question 6

what is the primary structure?

Answer 6

• order of amino acids in a polypeptide chain

Question 7

what is the secondary structure?

Answer 7

• causes parts of a protein molecule to fold into alpha helix shapes or beta pleated sheets

Question 8

what bonds hold the secondary structure?
where are these bonds?

Answer 8

• hydrogen bonds
• C=O groups OF the carboxyl group of one amino acid and the H group of the amine group of another amino acid

Question 9

what is the tertiary structure?
what bonds hold the structure in place?
how many sulfurs is needed in disulphide and where must the sulfur be in the amino acid?

Answer 9

• further folding of the secondary structure where a unique 3d shape is formed
• ionic hydrogen and disulphide
• the r groups of 2 different amino acids
• 2 sulphurs, in r group

Question 10

what is the quartenary structure?

Answer 10

• a protein made up of more than 1 polypeptide chain

Question 11

what happens when a protein denatures?
what are the conditions to denature a protein?

Answer 11

• the bonds holding the secondary and tertiatry structure in place break and the unique 3d shape is lost
• too high/low pH and temp

Question 12

what is the importance of the primary structure?

Answer 12

• it determines the location of WHERE ionic, hydrogen and disulphide bonds FORM and in turn results in what unique 3d shape is formed

Question 13

how is a dipeptide made? (2)
where are condensation reactions made?
how do peptide bonds link? (as in where)

Answer 13

• when amino acid monomers combine
  through the removal of a water molecule in a condensation reaction
• -OH from the carboxyl group of one amino acid joined with the -H from the amine group of another amino acid
• 2 different amino acids are linked by a new peptide bond from the carbon atom of one amino acid and the nitrogen atom of another

Question 14

how can a peptide bond be broken? what does there have to be?

Answer 14

• hydrolysis
• due to the presence of water

Question 15

Describe the chemical reactions involved in the conversion of polymers to monomers and monomers to polymers.
Give two named examples of polymers and their associated monomers to illustrate your answer.

Answer 15

Ignore reference to dimers.
A condensation reaction joins monomers together and forms a (chemical) bond and releases water;
4. 5.
A hydrolysis reaction breaks a (chemical) bond between monomers and uses water;
A suitable example of polymers and the monomers from which they are made;
3. and 4. Polymers must contain many monomers. 3. and 4: suitable examples include
• amino acid and polypeptide, protein, enzyme, antibody or specific
example
• nucleotide and polynucleotide, DNA or RNA
• Alpha glucose and starch/glycogen
• Beta glucose and cellulose.
If neither specific carbohydrate example is given, allow monosaccharide/glucose and polysaccharide.
3. and 4. Reject (once) reference to triglycerides.
A second suitable example of polymers and the monomers from which they are made;
Reference to a correct bond within a named polymer;
Reject reference to ester bond.

Question 16

Describe the chemical reactions involved in the conversion of polymers to monomers and monomers to polymers.
Give two named examples of polymers and their associated monomers to illustrate your answer.

Answer 16

Ignore reference to dimers.
A condensation reaction joins monomers together and forms a (chemical) bond and releases water;
4. 5.
A hydrolysis reaction breaks a (chemical) bond between monomers and uses water;
A suitable example of polymers and the monomers from which they are made;
3. and 4. Polymers must contain many monomers. 3. and 4: suitable examples include
• amino acid and polypeptide, protein, enzyme, antibody or specific
example
• nucleotide and polynucleotide, DNA or RNA
• Alpha glucose and starch/glycogen
• Beta glucose and cellulose.
If neither specific carbohydrate example is given, allow monosaccharide/glucose and polysaccharide.
3. and 4. Reject (once) reference to triglycerides.
A second suitable example of polymers and the monomers from which they are made;
Reference to a correct bond within a named polymer;
Reject reference to ester bond.