Answer to Question 1
In transformational grammar, deep structure refers to an underlying syntactical structure that links various phrase structures through various transformation rules. In contrast, surface structure refers to any of the various phrase structures that may result from such transformations. Many casual readers of Chomsky have misunderstood Chomsky's terms. They incorrectly inferred that deep structures refer to profound underlying meanings of sentences, whereas surface structures refer only to superficial interpretations of sentences. This is not the case. Chomsky meant only to show that differing phrase structures may have a relationship that is not immediately apparent by using phrase-structure grammar alone.
Answer to Question 2
A phoneme is the smallest unit of speech sound that can be used to distinguish one utterance from another (i.e., to change the meaning of a word). In English, phonemes are made up of vowel or consonant sounds, like a, i, s, and f. For example, the word sit contains the phonemes /s/, /i/, and /t/, and by changing the phonemes we can change the meaning of sit to sat, fat, and fit. Different languages use different numbers and combinations of phonemes. North American English has about 40 phonemes. Hawaiian has about 13 phonemes. Some African dialects have up to 60.
Function and structure of aquaporin
The age structure of human populations in West Africa and Western Europe, as of 2000.
The a helix, a common secondary structure in proteins
Chemical structure of lipids
Structure of the sliding clamp
Structure of the retina