Biological molecules Flashcards
Peptide bonds vs Tertiary structure bonds
peptide bond and disulfide bond are covalent bonds ;
differences
tertiary structure bonds are between, R groups / side chains, (of different amino acids ;
H bond / ionic bond / hydrophobic interaction, versus covalent peptide bond ;
A tertiary structure bonds apart from disulfide are not covalent
peptide bond, stronger / more thermostable, than, tertiary structure bonds / two named bonds;
peptide bond is between, carboxylic acid / COOH, and, amino / NH2, group (of the adjacent amino acid) ;
What is a macromolecule?
A large biological molecule such as a protein,nucleic acid or carbohydrate
What is a monomer?
A relative simple molecule which is used as a basic building block for the synthesis of a polymer.
many monomers are joined together in condensation reactions.
e.g nucleotides,amino acids and monomers
What is a polymer?
A giant molecule made from many similar repeating sub units joined together in a chain.
The sub-units are monomers.
E.g polysaccharides,proteins and nucleic acid
Define polysaccharide
A polymer whose sub-units are monosaccharides joined together by glycosidic bonds.
Define monosaccharide.
A molecule consisting of a single sugar unit with the general formula (CH2O)n
Define disaccharide.
A sugar molecule consisting of 2 monosaccharides joined together by a glycosidic bond.
What are isomers?
2 forms of the same chemical
Monosaccharides of maltose
glucose + glucose
Monosaccharides of sucrose
glucose + fructose
Monosaccharides of lactose
glucose + galactose
What is a glycosidic bond?
a C-O-C link between two monosaccharides formed by a condensation reaction
Define primary structure.
The sequence of amino acids in a polypeptide or protein
Describe secondary structure.
The structure of a protein molecule resulting from the regular coiling and folding of the chain of amino acids
e.g alpha helices,beta pleated sheets
Describe Tertiary structure.
The compact structure of a protein molecule resulting from the 3D coiling of the already folded chain of amino acids.
Describe Quarternary structure.
The 3D arrangement of 2 or more polypeptides or of a polypeptide and non-protein component such as Haem,in a protein molecule
Hydrophobic interactions occur between?
R groups which are non polar or hydrophobic
Disulfide bonds occur between?
Two cysteine molecules,which contain sulfur molecules.
What groups form Ionic bonds?
Ionised amine groups(NH3+)
Ionised carboxylic acid(COO)
Non-polar vs polar
Polar-differences in electronegativity between bonded atoms
Non-polar-when electrons are shared equal between atoms
What breaks down Ionic bonds?
pH changes
What breaks down disulfide bonds?
Reducing agents
Describe the structure of a globular protein
Non-polar hydrophobic R groups point to the centre of the molecule away from watery surroundings.
The polar,hydrophilic R groups-outside molecule
What is responsible for maintaining the solubilty of haemoglobin?
The outward pointing hydrophilic R groups.
Which polar amino acid is replaced by Valine( Valine causes sickle cell anemia)?
Glutamic acid
Describe the structure of haemoglobin
4 polypeptide chains.
2 B-chains-made of beta globin.
2 A-chains-alpha globin
Each polypeptide chain contains a haem group.
Each haem group contains an Iron atom.
1 oxygen molecule can bind with each iron atom.
A complete haem group with 4 haem groups can carry 4 oxygen molecules at a time. How many oxygen atoms can it carry?
8
A collagen molecule consists of how many polypeptide chains?
3,each in the shape of a helix(NOT AN A-HELIX)
Every 3rd amino acid in a collagen strand is
glycine
Three helices are wound together to form a
collagen molecule
What are fibrils?
Cross-links holding many collagen molecules side by side.
Name the advantages of collagen.
- Flexible
- Tensile strength
Why is water important?
-acts a solvent
-transport mechanism
-high specific heat capacity
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