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| Question | Answer |
| What do Amino Acids contain? | One Amino group and one carboxylic group. |
| What are bifunctional compounds? | Compounds with two functional groups. |
| Which functional group is proton donating? | -COOH (Carboxylic Acid) |
| Which one is proton accepting? | -NH2 (Amino Group) |
| What are Zwitterions? | Particles containing both negatively charged and positively charged groups. (Single molecule containing both + and -) |
| How do Amino Acids form Zwitterions? | By the two functional groups reacting with each other. |
| What do an aqueous solution of an amino acid mainly consist of? | Zwitterions as amino acids are very soluble in water because they are ionic. |
| Why might an amino acid not be ionic in water? | If it has an extra -COOH or -NH2 group in the molecule. |
| What do small quantities of acid or alkali to an amino acid solution do? | It causes little change to the pH because the zwitterions neutralise the effect of addition. |
| What are buffer solutions? | Solututions which can withstand the addition of small amounts of acid or alkali. |
| What is formed when NH2 reacts with the -COOH? | A secondary amide group. |
| When a secondary amide group is formed what molecule is eliminated? | Water therefore it is a condensation reaction. |
| What is formed when two amino acids are joined together? | A secondary amide is formed called a peptide link. |
| What is a polypeptide? | 3 or more amino acids joined together. |
| What is the primary structure? | The order in which the amino aids are joined to one another. |
| What four interactions are in chain folding? | 1. Instantaneous dipole-induced dipole bonds between non-polar side chains. 2. Hydrogen bonds between polar side chains. 3. Ionic bonds between ionisable side chains. 4. Covalent bonding. |
| What are the two ways a protein can be arranged as a result of folding and twisting from hydrogen bonding? | 1. Helix=Tightly coiled where the C=O group of one peptide link from a hydrogen bond to a N-H group four peptide links along the chain. 2. Sheet where the extended chains line alongside each other. |
| What are the helix and sheet also known as? | The secondary structure. |
| What happens when chains fold up further? | A tertiary structure forms where the instantaneous diple-induced dipole attractive forces, H bonding + ionic attractions + covalent bonding. |
| What can do done to release individual amino acids? | Peptide links can be hydrolysed. |
| How is Hydrolysis carried out? | By heating with moderately concetrated alkali or acid to hydrolyse the C-N bond. It is hydrolysd under reflux. |
| How does hydrolysis of proteins happen in living organisms? | By enzymes rather than acid or alkali. |
| What technique can be used to identify the individual amino acids present in a peptide? | Paper chromatography where the sample product can be compared to known samples of pure amino acids. |
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