PROTEINS N AMINO ACIDS

Question 1

what is amino acid?

Answer 1

monomer of proteins and polypeptides

Question 2

what is the structure of amino acid?

Answer 2

• primary amine group
• R-side chain
• carboxylic acid group
• hydrogen group

Question 3

significance of the R-side chain?

Answer 3

determines the properties of the individual amino acid

• size, shape, charge, reactivity, hydrophobicity
• know the essential amino acid

Question 4

what is the nature of amino acid?

Answer 4

L enantiomer except for glycine

- have mirror image (chiral) as - have four groups linked to alpha carbon have different molecular weights

Question 5

how can the R-side group be modified?

Answer 5

phosphate groups, carboxylic acid group and methyl group can be added or removed from the R group of AA

Question 6

histamine and dopamine are made from?

Answer 6

histidine and tyrosine

Question 7

what is primary structure?

Answer 7

sequence of adjoining AA is according to the messenger RNA code - order of AA sequence
- peptide bond is formed by a condensation reaction where one water molecule is removed

Question 8

what is secondary structure?

Answer 8

shape within a single protein

• alpha helix
• beta pleated sheet
• extended stem loop

Question 9

what is tertiary structure?

Answer 9

3D structure of the protein held by disulphide bonds

Question 10

what is quartenary structure?

Answer 10

overall structure of two or more proteins

- protein sequence determines structure

Question 11

what are the methods of purifying proteins?

Answer 11

• protein solubility in increasing salt
• protein binding to ion exchange beads
• hydrophobic interaction chromatography
• gel filtration chromatography
• affinity chromatography

Question 12

what are the functions of proteins and amino acid?

Answer 12

• proteins as enzymes
• derivatives functions as hormones
• protein in cell membrane structure

Question 13

disease associated with protein structure?

Answer 13

• sickle cell anemia ; sickle shaped red blood cells cannot pass through capillaries easily due to its shape
• allergens ; usually free from proteins that are released such as histamine made from histidine after removing carboxylic acid
• hemoglobin binds oxygen with heme cofactor

Question 14

what is oxygen affinity?

Answer 14

measures how readily oxygen binds ore releases oxygen

• high partial pressure in lungs, high oxygen affinity as oxygen binds readily to haemoglobin
• low partial pressure in body tissues, low oxygen affinity as the haemoglobin releases oxygen in the tissues