Biology is a broad topic with many details. However, we need to have an appreciation for the big picture of biology before we can dive into those details. Specifically, we need to gain an understanding of the chemical properties that govern biology. These chemical properties give biological systems their characteristic features, and they are also responsible for creating the various macromolecules that are essential to life.
In this introductory chapter, we will emphasize fundamental concepts that we will need to keep in mind for the duration of our biology journey. First, we will discuss biological chemistry and critical macromolecules, which are responsible for life as we know it - these include carbohydrates, proteins, lipids, and nucleic acids. Finally, we will look at biology in a more thought-provoking manner as we discuss central hypotheses and theories.
All of the stuff around us is called matter, which refers to any substance that takes up space and has mass. Matter is composed of elements, which we all know from the periodic table of elements. What is an element? An element is a substance that has specific chemical and physical properties.
Note: we have access to a periodic table during the Survey of Natural Sciences section of the DAT, so do not worry about memorizing the periodic table!
Adapted from: https://commons.wikimedia.org/w/index.php?curid=62296883
An atom is the smallest unit of matter that still retains all the chemical properties of an element.
Molecules result whenever two or more atoms join together. An example of a molecule is oxygen gas (O₂), which we breathe in every day. Organic molecules contain carbon atoms arranged as long chains or rings, and these carbon atoms tend to bond with hydrogen (H), oxygen (O), or nitrogen (N) atoms.