Amino acids and Proteins

Question 1

What are amino acids ?

Answer 1

The building blocks of proteins

Question 2

What are proteins ?

Answer 2

Proteins are the most abundant macromolecules in living cells

Question 3

Generally how many amino acids are needed to form a protein ?

Answer 3

About 20

Question 4

Why is every protein different ?

Answer 4

-Proteins are made by joining together amino acids to form polypeptide chains.
- The length of these chains can be from a few hundred to more than a thousand amino acids in length
- The Chains then fold up to make a 3D structure
- Each Amino acid in a protein has the same chemical structure except for its R group.

Question 5

What groups do amino acids contain ?

Answer 5

• Amino group ( NH2 )
• Carboxyl Group ( C00H )
• Hydrogen Atom
• R group ( different in each amino acid )

Question 6

What do the R groups determine ?

Answer 6

The properties of the amino acid in a protein

Question 7

What are the 4 different groups that an R group could be ?

Answer 7

• Neutral and non-polar = 9
• Neutral and polar =7
• Acidic = 2
• Basic = 2

Question 8

Give 2 reasons why the right R-group is important ?

Answer 8

• Proteins have to fold up into a particular shape to be functional. it is interactions between the R groups of amino acids that determine and maintain this shape
• When an protein carries out a chemical reaction, it is due to the R group of one or several of the amino acids reacting transiently with the substrate
  Therefore for either of these reasons, any changes in the R groups might destroy the function of the protein/

Question 9

What are the 9 essential amino acids ?

Answer 9

• Phenylalanine
• Valine
• Threonine
• Tryptophan
• Methionine
• Leucine
• Isoleucine
• lysine
  -Hyistoine

Question 10

What is the tyrosine conundrum ?

Answer 10

Caused by a lack of essential amino acids
- Accumulation phe (brain), phenylpyruvate in urine
- If untreated - severe mental retardation

Question 11

What is Kwashiorkor?

Answer 11

-caused by a lack of essential amino acids
-Normally the diet is adequate in energy but deficient in amino acids
- Symptoms – lethargy, irritability, protruding belly, changes in skin pigment, hair changes, increased infection due to damaged immune system.
-If not treated soon, permanent physical and intellectual disability can occur

Question 12

What is the glyphosate story ?

Answer 12

• Glyphosate or roundup inhibitss ESP synthase an essential enzyme of the Shikimic pathway for the production of aromatic amino acid
• Glyphosate or round up kills non selectively anything that is green
• plants resistant to glyphosate posses a mutated form of EPSP

Question 13

What is the structure like in amino acids ?

Answer 13

They are L-enantiomers and possess chiral centres

Question 14

what does the R chain that attached to the alpha carbon dictate ?

Answer 14

The properties of the AA

Question 15

What is a buffer ?

Answer 15

Buffers are solutions that resist changes in pH upon addition of acid or base

Question 16

Whats the function of nonapeptides ?

Answer 16

Stimulates uterine contraction during child birth

Question 16

in proteins how are amino acids linked ?

Answer 16

Covalently linked by peptide bonds

Question 16

What can th ph imbalance of the blood cause ?

Answer 16

Alkalosis or acidosis

Question 16

What are the properties of polypeptide chains ?

Answer 16

• Peptide bond is essentially planar
• Peptide bond has double bond character

Question 17

what are the 2 possible configurationns for planar peptide bond ?

Answer 17

Trans
Cis

Question 17

Whats the function of vasopressin ?

Answer 17

Stimulates water reabsorption by kidneys

Question 17

What is the function of pentapeptides ?

Answer 17

Regulates pain and emotional states

Question 18

Whats the function of tripeptide ?

Answer 18

Regulates ox/red and free radicals in cells

Question 19

What are the 5 forces during protein folding ?

Answer 19

• Hydrophobic interactions
• Hydrogen bonds
• Electrostatic attraction
• Metal ion coordination
• Covalent bridges

Question 20

How are beta sheets formed ?

Answer 20

Beta-sheets are formed from largely extended polypeptide strands that make hydrogen bonds between backbone groups of neighbouring strands

Question 21

What is critical to a proteins function?

Answer 21

The three-dimensional shape of a protein

Question 22

What is the structure like in a water soluble protein ?

Answer 22

Fold into compact structures with non polar cores.

Question 23

What is cystic fibrosis and how is it formed ?

Answer 23

Caused by a defect in primary structure
- Inherited disease
- Symptoms - chronic cough, wheezing, frequent respiratory infections, salty skin.
- in cf the exocrine glands produce a think, sticky mucous
- In CF the transport of cl- ions is seriously affected
- Mutations in cftr identified

Question 24

What is sickle cell anaemia and what is it caused by ?

Answer 24

• Inherited blood disease
• Symptoms - Chronic anemia and periodic episodes of pain
• in sick cell anaemia the defective hemaglobin in red blood cell affects the oxygen transport in blood and change the overall structure of the red cell
• Mutations in hemoglobin

Question 25

How many amino acids are considered essential in some stages of human life ?

Answer 25

10