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Chapter Summary:
In this chapter, we learned about many different chemicals and chemical compounds that exist in the human body. Atoms, Ions and Chemical Bonds started out Chapter 2. We then learned about carbohydrates including monosaccharides, disaccharides and polysaccharides. We also learned about lipids and their functions as phospholipids, steroids and prostaglandins. We also learned about protein function and their amino acid composition. The most complicated part of chapter 2 came at the end with the section about DNA and RNA. This section explained how new cells are formed and how DNA is replicated and transcribed. DNA is amazing and extremely complex.

Atoms, Ions and Chemical Bonds:
Atoms are the smallest possible unit of a chemical element. All molecules are formed using atoms. Atoms all have a nucleus. The nucleus contains both protons and neutrons. The protons are positively charged and the neutrons are neutral, carrying no charge at all. The electrons orbit the nucleus and form what are called valence shells around the nucleus of the atom.
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This carbon atom contains 6 electrons that orbit its nucleus. When an atom loses or gains an electron, it becomes charged (either positivly or negatively) and it becomes an ion. If an atom loses and electron, it becomes poitively charged and is known as a cation. If an atom gains an electron, it become negatively charged and is known as an anion.
In ionic bonds, one atoms transfers electrons completely over to another atom. One atom becomes a cation and one becomes an anion and the attraction of positive and negative charges to each other is what holes the ionic compound together.
In some chemical bonds, atoms share electrons equally and neither atom transfers any electrons to another atom. Below is a picture of a water molecule which has a polar covalent bond.
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When atoms share electrons equally, neither atom has a charged and the molecule is said to be non polar. In polar covalent bonds, one atoms pulls the electrons more towards it than does the other atom. The atom that does the majority of the pulling gets a negative charge and the other atom gets a positive charge. Water (as shown in the picture above) is a polar covalently bonded molecule composed of 2 hydrogen atoms and 1 oxygen atom.




Carbohydrates:
Carbohydrates consist of Hydrogen, Oxygen and Carbon atoms. A carbohydrate atom will always contain twice as many Hydrogen atoms as there are Carbon or Oxygen atoms. Carbohydrates make up the simple sugars that we digest to give our bodies energy. Carbohydrates can have the same composition of atoms but can be shaped differently to create different sugars. For example, Glucose, Galactose and Fructose all contain 6 Carbons, 12 Hydrogens and 6 Oxygens. Each one has a different shape and different properties than the other. These simple sugars can also combine to make disaccharides. Disaccharides are more than one sugar combined together. Some examples of disaccharides incluse sucrose, whihc is glucose and fructose, lactose which is glucose and galactose and maltose which is two glucose molecules combined together. Disacchardies can also combine together to form polysaccharides. Below is a picture of a basic polysaccharide, which is formed of three or more monosaccharides.
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Proteins:
Amino acids compose proteins. These amino acids each have an amino group of molecules (composed of 1 Nitrogen and 2 Hydrogen) on one end and a carboxyl group (composed of 1 Carbon, 2 Oxygen and 1 Hydrogen) on the other end. Each amino acid will bond with another amino acid to from a peptide bond and these peptide bonds will repeat forming a polypeptide. Proteins can be structured in four different ways. The first way is a primary structure which is a chain of amino acids bonded together. The second structure that these amino acids form is the secondary structure. In the secondary structure, the amino acids can form a pleated sheet or a helix. The pleated sheet is lines of amino acid chains bonded together both above and below one another. The helix is a spiral chain of amino acids. The third structure amino acids form is the tertiary structure which is a long helix of amino acids coiled in and around itself. When four or more tertiary structures bond together, they form the quaternary structure. Below is a picture that shows each different structure.
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Protiens have many different functions. They can be a structural protein like collagen or keratin. They can also be enzymes or antibodies. Proteins also act as receptor sites on cells. As receptors on cells, proteins lie in the cell membranes and are activated by certain hormones. Proteins can also carry specific molecules across celll membranes when the molecules cannot get across the membrane by themselves.

Application to Nursing:
Often times a nurse has to advise a patient on a specific diet, or benefits of avoiding certain ingredients in food. Saturated fats and fatty acids are composed of lipids such as triglycerides. Saturated fats can contribute to a rise in LDL cholesterol. LDL is the bad cholesterol that often contributes to heart disease. Saturated fats also can decrease levels of HDL cholesterol which is the good cholesterol. Cholesterol can build up on the walls of arteries and that can cause a blockage which can lead to a heart attack. As a nurse, we have to advise patients of diets that they should follow after having cardiac episodes. In the unit that I currently work in, we see a lot of patients that have had cardiac catheterization procedures done. Some have had stenting, some have not. The ones that have had stenting due to blocked arteries need to understand what foods they should be eating and what foods to avoid in order to prevent further or recurrent blockage of their arteries. Knowing how saturated fats work in conjunction with the body will help the nurse explain the process of arterial buildup to the patient. Patients usually don't have a vast understanding of physiological concepts or chemical concepts of how things work in the body. By knowing in detail these processes, the nurse can use language that will make sense to the patient when explaining the proper food choices for their condition.
Source of Cholesterol Information
Case Study/Essential Question:
"Describe buffer, their importance, and the buffering system (bicarbonate/carbonic acid) used in the blood to regulate the narrow range of pH in the blood. What is the difference between acidosis and alkalosis? What are enzymes? What role do they play in human physiology?"

The pH level of human blood must be maintained in a range of 7.35-7.45. This range is needed for proper oxygen delivery, and for metabolic processes to take place. The human body has its own system of regulation for pH levels. This system is the buffers of the human blood. Buffers act to keep stable levels of Hydrogen ions and work to keep changes from occuring. A change in Hydrogen ions in the blood can result in acidosis or alkalosis if the pH gets too low or too high. To create carbonic acid, a Hydrogen ion reacts with a bicarbonate ion. This action is reversible and the carbonic acid can be broke down into Hydrogen ions and bicarbonate ions. Bicarbonate is the major buffer in the blood system. Bicarbonate and carbonic acid work with each other to maintain a stable blood pH level. Carbonic acid will release free Hydrogen ions which help prevent a rise in pH levels and bicarbonate will react with free Hydrogen ions which helps prevent a drop in pH levels.
The differnce between acidosis and alkalosis is a difference between the body's pH being too low forming an acid (acidosis) and the body's pH too high forming a base (alkalosis). They are both abnormal conditions of the blood and result from the blood pH being either too high or too low. The normal range for the body's pH is 7.35-7.45. This range allows the metaboli process to function properly and assures the proper delivery of oxygen to the tissues.
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Enzymes are proteins that perform many different functions throughout the human body. By definition, they are catalysts and the rate of chemical reactions increases when enzymes are present. Enzymes play an extremely important role in physiology. They help us to break down our food that we eat, they help digest food once it is in the intestines. Enzymes help to regulate blood pH levels, they also help to regulate our metabolism.