Amino acids and Proteins Flashcards
What are amino acids ?
The building blocks of proteins
What are proteins ?
Proteins are the most abundant macromolecules in living cells
Generally how many amino acids are needed to form a protein ?
About 20
Why is every protein different ?
-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.
What groups do amino acids contain ?
- Amino group ( NH2 )
- Carboxyl Group ( C00H )
- Hydrogen Atom
- R group ( different in each amino acid )
What do the R groups determine ?
The properties of the amino acid in a protein
What are the 4 different groups that an R group could be ?
- Neutral and non-polar = 9
- Neutral and polar =7
- Acidic = 2
- Basic = 2
Give 2 reasons why the right R-group is important ?
- 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/
What are the 9 essential amino acids ?
- Phenylalanine
- Valine
- Threonine
- Tryptophan
- Methionine
- Leucine
- Isoleucine
- lysine
-Hyistoine
What is the tyrosine conundrum ?
Caused by a lack of essential amino acids
- Accumulation phe (brain), phenylpyruvate in urine
- If untreated - severe mental retardation
What is Kwashiorkor?
-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
What is the glyphosate story ?
- 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
What is the structure like in amino acids ?
They are L-enantiomers and possess chiral centres
what does the R chain that attached to the alpha carbon dictate ?
The properties of the AA
What is a buffer ?
Buffers are solutions that resist changes in pH upon addition of acid or base
Whats the function of nonapeptides ?
Stimulates uterine contraction during child birth
in proteins how are amino acids linked ?
Covalently linked by peptide bonds
What can th ph imbalance of the blood cause ?
Alkalosis or acidosis
What are the properties of polypeptide chains ?
- Peptide bond is essentially planar
- Peptide bond has double bond character
what are the 2 possible configurationns for planar peptide bond ?
Trans
Cis
Whats the function of vasopressin ?
Stimulates water reabsorption by kidneys
What is the function of pentapeptides ?
Regulates pain and emotional states
Whats the function of tripeptide ?
Regulates ox/red and free radicals in cells
What are the 5 forces during protein folding ?
- Hydrophobic interactions
- Hydrogen bonds
- Electrostatic attraction
- Metal ion coordination
- Covalent bridges
How are beta sheets formed ?
Beta-sheets are formed from largely extended polypeptide strands that make hydrogen bonds between backbone groups of neighbouring strands
What is critical to a proteins function?
The three-dimensional shape of a protein
What is the structure like in a water soluble protein ?
Fold into compact structures with non polar cores.
What is cystic fibrosis and how is it formed ?
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
What is sickle cell anaemia and what is it caused by ?
- 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
How many amino acids are considered essential in some stages of human life ?
10
