Describe the structure of the personality according to the psychodynamic approach in psychology

The fundamental concept of the psychodynamic approach is that the personality is tripartite. The theory was originated by Freud, who stated that the personality could be divided into the id, ego and superego.
The id is it is the biological part (instincts and drives) of the personality. It is present at birth. The Id is motivated by the pleasure principle; it demands instant gratification of its needs. The ego develops between the ages of 1 - 3 years. It is motivated by the reality principle. It mediates the conflicts between the ID and superego. It uses defence mechanisms to achieve this, such as repression (which is used by the ego to keep disturbing memories out of the conscious mind and in the unconscious mind where they cannot be accessed, e.g. sexual or aggressive urges or painful childhood memories), displacement and denial. Finally, there is the superego, which develops from 3 - 5 years. It is motivated by the morality principle. It punishes the ego with guilt for “wrong doing”.
Another aspect of Freud's theory is the idea of the psychosexual stages of development. They are the oral, anal, phallic, latent and genital stages of development. At each stage, there is a conflict that must be resolved. Lack of resolution at each stage results in remaining at that stage-- that is, retaining behaviours associated with that stage.