Biochemical Aspect of Biology L. Jones

All living things are made of various chemicals All living things are made of various chemicals. In order to understand life, you must understand some basic concepts of chemistry. The chemistry of living organisms is called biochemistry.

Biochemistry includes the concepts of atomic structure, chemical bonding, and pH, all of which are important to living organisms. During this unit we will look at these concepts more closely.

Draw a circle with 8 lines radiating from the circle (See example)

8 Characteristics of Living Things All living things are made of 1 or more cells. All living things have a way to reproduce. All living things grow and develop. All living things share a universal genetic code (Have DNA and RNA) All living things must obtain material and use the energy from them. All living things maintain a fairly stable internal environment. All living things are able to respond to environmental changes. As a group, living things change over time(evolve)

Atoms Atoms are the basic unit of matter. They are made up of 3 subatomic particles Protons Have a positive charge Found in the nucleus Neutrons Have no charge/neutral Electrons Have a negative charge Found in a orbital/cloud surrounding the nucleus

Picture of an Atom

Things to Know

Picture of an Atom

Energy levels Electrons orbit the nucleus at different distances, which are called energy levels. The first level holds 2 electrons, the second holds 8, the third holds 18 electrons and so on. Valence electrons are the electrons found in the outer level.

Energy Levels Atoms tend to gain or lose the least number of electrons as possible. To become stable elements will gain, lose, or share electrons with other elements in order to have 8 electrons in their outer energy level. This principal is known as the octet rule.

Element Is one particular type of atom and cannot be broken into a simpler substance by ordinary chemical means. Of the 91 elements that naturally occur on Earth, only about 25 are found in organisms. Just 4 elements – carbon (C), oxygen (O), nitrogen (N), and hydrogen (H) make up 96% of the human body’s mass.

Isotopes are the same element, but may have different properties because of their different masses that may change its stability. Isotopes are named by adding the number of protons and neutrons. Some isotopes are useful in telling the age of fossil

Bonding valence

Compounds and Ions Is a substance made of atoms of different elements bonded together in a certain ratio. ie water (H2O). An ion is an atom that has gained or lost one or more electrons. Ions form because an atom is more stable when its outermost energy level is full. They can be + or -.

How can you tell if it is ionic or covalent? An ionic bond occurs between a metal and a non-metal. A covalent bond occurs between two non-metals. Unless you memorized the periodic table, you're going to need a periodic table.

Oxygen atom Hydrogen atoms Oxygen atom Hydrogen atoms

Cohesion Notice the balls of water. Water is pulling itself together to form the balls. This is cohesion.

Since water molecules are strongly attracted to one another (hydrogen bonds), water is very cohesive. Cohesion can also be observed on its surface as surface tension (property that gives it a skin-like quality on its surface. This is what allows insects to “skate” across the surface of a pond.

Adhesion

Water Continued

Example + = solvent solute solution

Water and Temperature Water’s bond also allows water to float when it is frozen, which means it is less dense than its liquid state. If ice sank, frozen bodies of water would not be able to support aquatic life. Water also has high specific heat(energy needed to raise the temperature of one gram of a substance by one degree Celsius)

High specific heat is an important property of water High specific heat is an important property of water. Water regulates and maintains a fairly constant temperature in living things. It takes a lot of heat to raise the temperature of water. …. Water covers around 70% of the planet. It also helps regulate the temperature of the Earth.