Exam 1 Chapter 2 Chemical Level of Organization

1. What are the major elements found in the human body?

Oxygen (O) Carbon (C)
Hydrogen (H) Nitrogen (N)

These four elements make up about 96% of the human body.

Positive ion:

is called a cation

It forms when an atom loses electrons

Example: Na⁺ (sodium ion)

Negative ion:

is called an anion

It forms when an atom gains electrons

Example: Cl⁻ (chloride ion)

Unstable element:

is called a radioactive element (or radioisotope)

Its nucleus is not stable, so it breaks down over time

Emit radiation?

Uranium Carbon-14 Radium 

4. What can conduct an electrical current when dissolved in water?

Electrolyte.

5. The different types of chemical bonds and do they share electrons equally or not? An example of ones shared unequally.

Ionic Bond

Electrons are not shared.
One atom gives electrons and another atom gains electrons, forming positive and negative ions that attract each other.
Example: Sodium chloride (NaCl).

6. What is involved in an atom during a chemical reaction? The whole atom or just what is being shared?

During a chemical reaction, only the electrons in the outermost energy level (valence electrons) are involved.The entire atom is not involved. The nucleus (protons and neutrons) stays the same, and only the electrons that are shared, gained, or lost participate in forming or breaking chemical bonds.

7. What is the definition of energy?

Energy is the ability to do work or cause change.

9. What are catalysts and how do they help with reactions?

Catalysts are substances that speed up chemical reactions without being used up or permanently changed in the reaction.

What are the catalysts our body uses?

They help reactions by lowering the activation energy, which means the reaction can happen faster and more easily

The catalysts used in the human body are called enzymes.

Enzymes are proteins that help control and speed up chemical reactions needed for processes like digestion, metabolism, and energy production

Organic compounds:

Contain carbon and hydrogen and are usually made by living organisms.

They are typically larger and more complex molecules.

Examples in the body:

Carbohydrates (glucose, glycogen) Proteins (enzymes, muscle proteins)

Lipids (fats, cholesterol) Nucleic acids (DNA and RNA)

Inorganic compounds:

Usually do not contain carbon bonded to hydrogen and are generally simpler molecules.

Examples in the body:

Water (H₂O) Salts (sodium chloride) Oxygen (O₂) Carbon dioxide (CO₂)

Minerals like calcium and potassium.

Hydrophilic:

Means “water-loving.” These substances attract and dissolve in water because they have charged or polar parts.
Example: salt or sugar dissolving in water.

Hydrophobic:

Means “water-fearing.” These substances do not mix with or dissolve in water because they are nonpolar.
Example: oil or fats separating from water.

13. What polysaccharide is stored for energy use?

Stored for energy use in the human body is glycogen.

Glycogen is the storage form of glucose and is mainly stored in the liver and muscles. When the body needs energy, glycogen is broken down into glucose and released into the bloodstream to be used by cells.

14. What type of lipids do we use to store energy?

Lipids used to store energy: Triglycerides. These are stored in fat tissue and used by the body for long-term energy storage.

What lipid do we make hormones from?

Lipids are used to make hormones: Cholesterol. The body uses cholesterol to produce steroid hormones such as estrogen, testosterone, and cortisol.

15. What helps us to lower the amount of free radicals in our body?

Antioxidants help lower the amount of free radicals in the body.

Antioxidants work by neutralizing free radicals, preventing them from damaging cells.

Examples of antioxidants include:Vitamin C Vitamin E Beta-carotene (a form of vitamin A)

16. Define metabolism

Metabolism is the sum of all chemical reactions that occur in the body to maintain life.

Breaking down molecules to release energy (catabolism)
Building molecules needed for growth and repair (anabolism).