In amino acid terms the difference between tyrosine and phenylalanine

is that tyrosine is a nonessential amino acid C₉H₁₁NO₃ found in most animal proteins, especially casein while phenylalanine is an essential amino acid C₉H₁₁NO₂ found in most animal proteins; it is essential for growth; the inability to metabolize it leads to phenylketonuria; it is a constituent of aspartame.

As nouns the difference between poetics and aesthetics

is that poetics is the theory of poetry, or of literature in general while aesthetics is the study or philosophy of beauty.

As an adjective rugged

is broken into sharp or irregular points; uneven; not smooth; rough or rugged can be having a rug or rugs.

As a verb rugged

is (rug).

As a noun hunk is

a large or dense piece of something.

As an adjective cyclic is

characterized by, or moving in cycles, or happening at regular intervals.

As nouns the difference between memoir and monument

is that memoir is an autobiography; a book describing the personal experiences of an author while monument is monument.

As a noun hierarchy is

a body of authoritative officials organized in nested ranks.

As nouns the difference between drawback and limitation

is that drawback is a disadvantage; something that detracts or takes away while limitation is the act of limiting or the state of being limited.

As nouns the difference between thrall and lackey

is that thrall is one who is enslaved or under mind control while lackey is a footman, a liveried male servant.

As verbs the difference between thrall and lackey

is that thrall is to make a thrall while lackey is to attend, wait upon, serve obsequiously.

In biology terms the difference between morph and metamorphosis

is that morph is local variety of a species, distinguishable from other populations of the species by morphology or behaviour while metamorphosis is a change in the form and often habits of an animal after the embryonic stage during normal development. (e.g. the transformation of a caterpillar into a butterfly or a tadpole into a frog..

As nouns the difference between morph and metamorphosis

is that morph is a physical form representing some morpheme in language. It is a recurrent distinctive sound or sequence sounds while metamorphosis is a transformation, such as that of magic or by sorcery.

As a verb morph

is to change shape, from one form to another, through computer animation.

As a noun lackey is

a footman, a liveried male servant.

As a verb lackey is

to attend, wait upon, serve obsequiously.