Page 2 Science Study Guide for the TEAS

Life and Physical Sciences

The newest version of the ATI TEAS (TEAS 6) has de-emphasized the area of Earth science in favor of focusing on the biological and chemical realms of study. These are, after all, more relevant to nursing practices. Be sure you understand the following terms and ideas before taking the test.


Macromolecules are large molecules necessary for life. The major macromolecules are carbohydrates, lipids, proteins, and nucleic acids. These perform a large range of functions involved in survival and growth. Humans get most of the macromolecules they need from their food and are able to synthesize some proteins from combinations of other macromolecules.

Additional terms to become familiar with include: monomer, polymer, dehydration synthesis, hydrolysis, monosaccharide, disaccharide, polysaccharide, glycogen, starch, amylose, amylopectin, cellulose, chitin, amino acid, peptide bond, polypeptide chain, globular protein, fibrous protein, enzyme, activation energy, active site, hydrocarbon chain, hydrophobic, fatty acid, triglyceride, saturated and unsaturated fatty acid chain, nucleotide, ribonucleic acid (RNA), adenosine triphosphate (ATP).


Heredity is the mechanism by which genetic information is passed from parent to child. This genetic information can code for certain traits, such as eye color. The genetic information that is passed on is held in the DNA, which is made of nucleic acids. Over many generations, the passing on of some traits, while failing to pass on others, can lead to the evolution of a species.


DNA stands for deoxyribonucleic acid and is the fundamental genetic building block in humans and almost all other life. Most of the DNA is held in the nucleus of the cells. It is made up of four chemicals that match up together in pairs: adenine goes with thymine and guanine goes with cytosine. From just these four chemicals, every gene and chromosome and protein can be made. It is important to know that DNA can replicate itself, which allows for the creation of new cells.


DNA strands in cells are very long and thin and are curled into structures called chromosomes. Humans have 23 pairs of chromosomes (46 total chromosomes) in each cell, except for sperm and ova which have only one set of each chromosome (23 in total). Normally, two strands of DNA are complementary and form a double helix, but when cell division takes place, the two strands of the helix separate and are copied, eventually resulting in two sets of double helixes and two sets of chromosomes—one for each of the new cells.


Genes are made up of DNA and each chromosome may contain many genes. Genes contain the genetic instructions with which to make proteins. Every person has two copies or alleles of every gene—one inherited from each of their parents. Most genes are the same in every person, but some, such as the genes that determine eye color, are different. Genes can either be dominant or recessive, and if an organism has one of each, the dominant gene is the one that will be expressed. For example, a person might have a dominant gene for green eyes and a recessive gene for grey eyes—as a result they will have green eyes. Incomplete dominance and codominant genes also exist.

Mendel’s Laws of Heredity

Johann Gregor Mendel discovered the laws of heredity when studying pea plants. They are as follows:

  • The law of segregation: Each inherited trait comes from a pair of genes, one from each parent.

  • The law of independent assortment: Genes on different chromosomes are kept separate from each other so that the inheritance of one trait does not depend on the inheritance of another.

  • The law of dominance: If a pair of genes is made up of one dominant and one recessive gene, the dominant gene will be expressed.

Make sure you are also familiar with this additional vocabulary: mitosis, meiosis, diploid, haploid, gamete, zygote, allele, homozygous, heterozygous, dominant, recessive, genotype, phenotype, incomplete dominance, codominance, Punnett square, X-linked, monohybrid cross, dihybrid cross.


The TEAS test requires you to not only demonstrate your understanding of anatomy and biology but also of chemistry. Through your nursing career, it will often be important to be able to understand and implement chemistry concepts.

Basic Atomic Structure

Atoms are the building blocks of all chemicals. They are composed of three types of particles―positively charged protons, negatively charged electrons, and neutral neutrons. Protons and neutrons make up the nucleus, the central part of the atom. Electrons orbit the nucleus in shells and most of the volume of the atom is taken up by the space between the nucleus and the electrons. An element’s nuclear symbol reveals how many protons, electrons, and neutrons make up an atom. It is important to be able to recognize atomic structure.

Characteristic Properties of Substances

Substances can be made up of pure elements or pure compounds, but not mixtures of elements or mixtures of compounds. Substances must have a definite chemical composition and distinct chemical properties. A pure substance cannot be made into simpler components without some chemical change taking place.

Characteristic properties of substances include their freezing or melting point and their boiling or condensing point, as well as properties like color and density.

Important terms include: substance, mixture, physical property, chemical property, extensive property, intensive property, density, melting point, boiling point, specific heat capacity, malleability, polar molecule, cohesive, adhesion, aqueous solution, solution, solvent, solute, diffusion, osmosis.

States of Matter

Matter may exist in three main states: solid, liquid, or gas. The state that matter is in is dependent on temperature. For example, at room temperature, water is a liquid; but, below its freezing point of 0ºC, it changes state and becomes a solid, ice. Likewise, above its boiling point of 100ºC, it changes state and becomes a gas, steam. Other substances and mixtures also exist in these three states and have their own freezing/melting and boiling/condensing points. When a substance or mixture goes from one state to another, we call this a change of state. It is important to be able to compare and contrast the changes of state in matter.

Terms to remember include: intramolecular force, intermolecular force, crystal, phase transition, freezing point, evaporation, vapor, condensation, latent heat, latent heat of fusion, latent heat of vaporization, calorie, phase diagram, triple point, critical point, sublimation, deposition.

Chemical Reactions

Chemical reactions can occur when particles collide with each other under the right conditions. The minimum amount of energy required to start a reaction is known as the activation energy and is the amount of energy required for a specific reaction to occur. The rate of a reaction can be increased by increasing the temperature, pressure, or concentration and by adding a catalyst. In industry, iron is added to catalyze the reaction between nitrogen and hydrogen which makes ammonia. It is important to be able to describe chemical reactions.

Related terms are: ionic bond, covalent bond, organic molecule, reactant, product, chemical equation, single displacement reaction, substitution reaction, double displacement reaction, molecular ion, polyatomic ion, decomposition reaction, synthesis reaction, direct combination reaction, combustion, oxidation reaction, exothermic, endothermic, catalyst, pH, acidity, alkalinity/basicity.

The Periodic Table

The 118 known elements are displayed on the periodic table in a specific order. Progressing from left to right and top to bottom on the table, the elements increase in atomic number. A row in this table is called a period and a column is called a group. The elements in each row and group share certain properties.

These are further associated terms: atomic number, atomic mass, atomic mass unit (amu), period, group, noble gas, metal, element, compound, orbit, orbital, cloud orbit, isotope, neutral atom, ion, cation, anion, shell, subshell, electron configuration, valence electron, octet rule.

Scientific Reasoning

Scientific reasoning questions on the ATI TEAS test are designed to evaluate your ability to answer questions and problems using scientific methods and inquiry. Focused on different areas of science, these questions require the use of logic and reason to find the correct answer. They may be presented as a word problem, requiring scientific knowledge and math skills to respond accurately.

The Scientific Method

A key scientific reasoning concept to know is the Scientific Method. The Scientific Method involves six steps: problem identification, question asking, hypothesis development, data collection, analysis, and conclusion. The first two steps enable the formulation of the hypothesis. Data collection involves the collection of facts through a scientific method, in a controlled environment, to test the hypothesis. In the analysis step, the data are analyzed to see if they support the hypothesis. The conclusion states whether the data analyzed are consistent with the hypothesis.

Other related terms are: experiment, null hypothesis, dependent and independent variable, experimental group, control, control group, controlled variable, bias, reproducibility.

Lab Measurements

To collect data, some lab measurements are required. The nature of these measurements will depend on the question that is asked. Tools such as thermometers and scales might be used to determine the effect of temperature or weight, for example. For these measurements to be reliable and useful, it is important that they are carried out in a methodical way. It is important to be able to identify different lab measurements and the tools with which they would be carried out.

The Metric System

The metric system of measurement is widely used in scientific and medical settings. Each basic unit (meter, gram, liter, etc.) is enlarged or reduced by a multiple of 10 using a certain prefix. Numerically, measurements can be expressed in alternate units by moving the decimal point to the left or right.

Important terms to consider are: graduated cylinder, volumetric flask, volumetric pipette, measuring wheels, electronic balance, triple beam balance, causality.

Scientific Critique

Scientific critique is necessary to evaluate the quality of a scientific experiment. This may take the form of deciding whether the data collected is the right kind of data with which to answer the question, or if there is enough of it. Or it might mean carefully considering whether the conclusions drawn from an experiment actually fit that data. For example, is the scientist making the mistake of assuming that because two things are correlated, one must cause the other, without the necessary information to make that assumption? Without a proper scientific critique, it is easy to draw the wrong conclusions from research findings. It is important that you are able to critique scientific experiments using logic and the available evidence.


Between different variables (e.g., height, temperature, pressure), there can be several relationships. Two variables might be correlated, i.e., when one increases, so does the other, or they might be inversely correlated, i.e., when one increases, the other decreases. On the other hand, they might not be correlated at all. In some cases, they might be correlated because one variable is causing the other, but it’s important to consider what other variables might be involved that aren’t immediately apparent. Usually, we try to remember that “correlation does not imply causation.” However, it is important to study relationships between different variables, events, objects, and procedures and to be able to explain these relationships logically.

Scientific Analysis

In the scientific analysis stage of a scientific experiment, the hypothesis is considered in the context of the data and results obtained. In many cases, this is compared to a “null hypothesis” and an attempt is made to decide which hypothesis best fits the available data. If the data demonstrate that a hypothesis is incorrect, a new one is needed; in some cases, a new experiment must be carried out. To decide if the data support a hypothesis or not, the experiment must have been suitably designed so that the data gathered actually answers the question asked. It is important to be able to analyze the design of an experiment or a scientific investigation.