Psychological Service Bureau (PSB) Study Guide

Natural Sciences

This part of the test determines a person’s accumulated information of the Natural Sciences on a fundamentallevel. Knowledge of the Natural Sciences (biology, chemistry, health, safety, etc.) is important to the course of study of Nursing and Allied Health program.

There are certain concepts that are related to Natural Sciences, which must be understood as essential points of information:

Basic Concepts Related to Natural Sciences

  • Atoms are the smallest units of matter
  • Atoms are bound together to form molecules…the building blocks of living cells.
  • Cells are the building blocks of all plants and animals.
  • Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA0 are compounds that store and process unique genetic information within the nucleus of a cell.
  • Heredity is the transmission of genetic information within the nucleus of a cell.
  • Mature cells bind together in distinct patterns from tissues; tissues unite to form organs, and organs unite to form the systems of a body.

All life processes are based on metabolism…chemical reactions that capture, store, and use energy in a cell.

  • All cellular functions depend on specific types of proteins, especially enzymes.
  • Chemical breakdown is the result of enzymes and activators.
  • Homeostasis is the constant maintenance of internal balance…a major part of metabolism.
  • Continuos regulation of internal conditions (such as levels of substances in cells or body fluids or pH or temperature) are kept within narrow ranges.

All life processes are controlled through body systems:

  • In animals, the respiratory system transports oxygen to the blood and eliminates carbon dioxide from the blood.
  • In animals, the circulatory system transports all nutrients to the cells and wastes from the cells.
  • In animals, the digestive system chemically breaks down foods and delivers nutrients to the circulatory system.
  • In animals, the excretory system removes metabolic waste excess substances from the body.
  • In animals, the musculoskeletal system generates motion and maintains posture.
  • In animals, the nervous system communicates internally to control and coordinate all body activities in response to environmental stimuli (light, temperature, touch, and other physical conditions).

All living forms need interdependent relationship with other living forms: they form complex relationship that are determined by their environment.

  • The kinds and amount of life found in different environments is determined by temperature, light, moisture, and soil.
  • All animals depend on food (food chain).
  • Food chains exist because all living things need energy.
  • Only organisms with chlorophyl can make food.
  • Inorganic matter is synthesized into food for plants; plants provide food for animals.
  • Living organisms in the same environment form an interrelated community and form close associations with one another (symbiosis).
  • These close associations either benefit both partners (mutualism) or benefit one partner at the expense of the other (parasitism).

Conservation of resources

  • Supplies of natural resources can be depleted.
  • Supplies of natural resources can be expanded (to some extent) through new ways of increasing food production; developing new sources of energy; recycling of waste materials; conserving natural habitats and soil.

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