Intro to Bio-molecules Flashcards
define atoms
‘incapable of being divided’
define (Bio/macro) Molecules
two or more atoms
define cells
smallest living units
define tissue
similar cells with common function
define organs
two or more tissue types
define organ system
cooperative group of organs
define ionic bonding
The electrostatic attraction between oppositely charged ions e.g. NaCl
define covalent bonds
sharing of electrons e.g. CH4
what does equal sharing of electrons give in covalent bonds
non polar bond e.g. CH4
what does unequal sharing of electrons give in covalent bonds
polar bond e.g. water
describe hydrogen bonds
-hydrogen that is covalently attached to an electronegative atom forms attraction with another v electronegative atom
-they are directional bonds so donor hydrogen and acceptor have to be in same plane e.g. DNA nucleotides
-H bonds are important for DNA and 2° protein structure
describe electrostatic forces
-oppositely charged groups attract each other
-amino acids can be ionised and can have interactions between them
-weakened by water and salts becasue they are charged so will compete for electrostatic attraction
-charge on amino acids change according to pH
-this force forms between enzymes and substrate
Describe Van der Waals forces
-non specific attraction
-transient asymmetry of electron distribution induces the same in other atoms and an attraction occurs bw the two
-Weak but significant when a number can form at close distance
describe the bonds in water
-Biologically important- solvent for large array of molecules
-Electrically polar bc +ve H and -ve O
-Hydrogen bonds- highly cohesive
-Weakens electrostatic & hydrogen bonds
-Nonpolar groups/molecules cluster in water – hydrophobic attractions
-Water-free microenvironments needed for polar reactions bc water will interfere w electrostatic and hydrogen bonds
give polymer for fatty acid
Diglyceride, Triglyceride
give polymer for monosaccharide
Polysaccharide
give polymer for amino acid
protein
give polymer for nucleotide
nucleic acid (dna, rna)
describe lipids
-structurally diverse
-insoluble in water
-do not form large polymers bc no end to end bonding
what are the functions of lipids?
Cell membranes (phospholipids)
Storing energy
Insulation, protection & absorbing shocks
Controlling cell activity (steroid hormones)
what are fatty acids?
long chain carbon molecules which can be saturated or unsaturated
what is a triglyceride?
a neutral fat made up of glycerol (sugar alcohol) and three fatty acids
what is a phospholipid?
lipids made of glycerol, phosphate and two fatty acids (one FA replaced with phosphate)
what is a sterol?
Cholesterol, steroid hormones
