introduction to biomolecules Flashcards
what are bonds dependent on and when is it most stable?
dependent on the arrangement of electrons in the outer shell of each atom. most stable when full
what is an ionic bond
transfer of electrons between metals and non metals
what is a covalent bond and what is polar and non polar
when electrons are shared
: polar - unequal charge
: non polar - equal sharing of electrons
purpose of non covalent bonds and examples
- stabilise molecules, have lower energy than covalent
- hydrogen, electrostatic and van der waal
- individually weak and collectively strong
what is hydrogen bonding and where is it found?
- hydrogen that is covalently attached to an electronegative atom (oxygen or nitrogen) has an attractive interaction with another electronegative atom
- highly directional and strongest when atoms involved are co linear
- H bonds are important in the stabilisation of dna and secondary structures of proteins
electrostatic and how are they weakened
- charged groups within the biomolecules can be electrostatically attracted to oppositely charged groups
- weakened by water and salt
- changes w ph
- eg amino acids can be charged and these electrostatic interactions are important in enzyme substrate complex formations
van der waals
- weakest non covalent bond
- individually weak but collectively strings
- forces only come into play when molecules are in close proximity
three properties of water
- solvent
- polar therefore acts as a solvent (h bonds get weakened)
- hydrogen bonding therefore highly cohesive
how does the polarity and cohesion come about in water
- water is a triangular shape and the polarity comes from the partial positive charge on the hydrogen atoms and the partial negative charge on the oxygen
- the cohesive properties are due to the hydrogen bonding
name four monomers and their polymers
monosaccharide - polysaccharide
amino acids - protein
nucleotide - nucleus acid (dna and rna)
glycerol and fatty acid - diglyceride and triglyceride
why are lipids insoluble in water
as they are hydrophobic
name three types of lipids
fatty acids, phospholipids and cholesterol
name four functions of lipids
- make phospholipids (in membrane)
- stores energy
- insulation, protection and absorbing shock
- controlling cell activity (steroid hormones)
fatty acid chain
- can be of varying lengths
- saturated
- unsaturated (no double bonds)
what are phospholipids made of
- two fatty acids, one phosphate attached to glycerol
- main components of the membrane which surround cells and intracellular organelles
what are triglycerides made of
- three fatty acids and glycerol
- fatty acids chain can be saturated or unsaturated
low density lipoprotein
- carry fatty acids and cholesterol around the body
- precursors for the formation of bile salts, steroid hormones and vitamin D
- high levels of lipoprotein associated with development of atherosclerosis
what are sterols
- cholesterol steroid hormones with overlapping C-H rings
what is the basic carbohydrate unit and how are they classified
- monosaccharides
- classified according to the chemical nature of their carbonyl group (aldehyde or ketone) and no. of carbon atoms (hexose 6C, heptose 7C)
three functions of carbohydrates
- store short term energy
- structural materials
- contribute to structure of nucleotides
how are amino acids linked
- condensation reaction and amino acids linked by peptide bonds
6 functions of proteins
- cell transport
- contraction
- signalling
- enzymes
- cell attachment
- structure, muscle, hair
function of collagen
- support for tissue and skin
- most abundant protein in body
- dentin and bone are mineralised collagen
- cross linked helix
function of nucleotides
- stores information needed to control and build cells
