Chapter 2 review

What is an element?

An element is matter that cannot be divided by ordinary chemical processes into another substance

What is chemical symbol?

A chemical symbol uses a letter or letters to refer to elements. Chemical symbols are derived from the element's name in English, Latin, or Greek

Name the three subatomic particles

Protons, neutrons, and electrons

What are the electrical charge of each particle?

Protons are positive electrical charge, neutrons are no electrical charge (neutral), and electrons have a negative electrical charge

Which particles are in the nucleus of the atom?

Protons and neutrons

How many electron shells would an atom with four electrons have?

two, two electrons in the first shell and two in the outer shell

What is a molecule?

Molecules are atoms joined together by chemical bonds

How does an ionic bond differ from a covalent bond?

A covalent bond is the bond formed when atoms SHARE electrons. An ionic bond is when electrons are TRANSFERRED from one atom to another

In what circumstance is a hydrogen bond commonly used?

Hydrogen bonds are formed mostly between molecules (ex., between H2O molecules) and act to stabilize the solution. Hydrogen bonding is the key to water's unique properties as a universal solvent and a medium for the life processes. Hydrogen bonds can also form between parts of the same molecule. This works to stabilize and holds the shape of large complex molecules such as proteins and DNA

What is a chemical reaction?

A chemical reaction is a change or transformation in a substance during the formation or breaking of chemical bonds

What are three chemical reactions?

Synthesis reaction : a new, more complex chemical is made from multiple, simpler chemicals. A decomposition reaction is a complex substance breaks down into its simpler forms. An exchange reaction is when certain atoms are exchanged between molecules. It is a combination of a synthesis and a decomposition reaction

The process of catabolism uses which type of chemical reaction?

decomposition reaction

What factors influence the rate of chemical reactions?

The rate of a chemical reaction is influenced by (1) the availability of the reactants, referred to as the CONCENTRATION OF REACTANTS. The more reactants that are available, the more likely they will come into contact and be able to react with one another. (2) The TEMPERATURE of the environment. when temperature increases, the speed of molecular movement increases & the chance of molecules meeting improves. Temperature also increases the velocity at which the reactants meet & the velocity provides the energy for the reaction. (3) ACTIVATION ENERGY is the energy required for the reaction to happen. Some reactions have an higher activation energy & require an input of more energy for the reaction to occur. These reactions will occur at a slower pace. (4) Certain reactions require the presence of an catalyst. In living organisms, catalyst-protein is not destroyed or used up by the reaction, & the reaction speeds is increased when there are more catalyst proteins are present. These special catalyst-proteins are called enzymes

What is the difference between organic and inorganic compounds?

Organic compounds are molecule that contain hydrocarbon groups ( H+ & C) and usually are covalently bonded. Inorganic molecules do nor contain hydrocarbon groups. They are usually ionic bonding.

Are only organic compounds necessary for life?

No, both organic and inorganic compounds are necessary for life on earth.

What are three types of inorganic molecules that are important for life?

H2O, salts, & acids and bases

What are the four types of organic molecules that are important for life?

carbohydrates, lipids, proteins, & nucleic acids

Why is water called a "polar" molecule?

It has a slight positive charge in the area of the H+ atoms & a slight negative charge in the area of the O atom. This polarity allows H2O molecules to form hydrogen bonds with each other & with other polar molecules

What are the four properties of H2O that make it necessary for life?

(1) H2O is the universal solvent. (2) H2O is an ideal medium. (3) H2O has high heat capacity and high heat of vaporization. (4) H2O is used for lubrication

How is an ion different from an atom?

Atoms are neutral. They contain the same # of protons as electrons. An ion is an electrically charged particle produced by either removing electrons from a neutral atom to yield a positive ion or adding electrons to a neutral atom to yield a negative ion

What is an electrolyte?

Electrolytes are substances that have the ability to transmit an electrical charge

What are some examples of electrolytes?

Sodium, potassium, & calcium are example of electrolytes.

What type of compound is known as a proton donor, acid or base?


What does pH measure?

The pH of a solution is measure of it's acidity or alkalinity

Is a solution with a pH of 8.5 acidic or basic?


How does a weak acid act as a buffer?

It helps the cell maintain a neutral pH by not allowing excessive (H+) hydrogen or (OH) hydroxyl ions to accumulate. In H2O, a weak acid will initially ionize into: (1) free hydrogen (H+) ions, (2) a weak base product, & (3) remaining intact weak acid molecules. The pH of the solution is not changed much because some of the chemical remains in acid form and some in the form of a weak base.

What three elements are found in all carbohydrates?

Carbon, hydrogen,& oxygen

What is the name of a simple sugar?


What process joins multiple simple sugars?

dehydration synthesis

What is another name for a complex, multiunit carbohydrate?


What three elements are found in all lipids?

carbon, hydrogen, and oxygen

Which atoms makes up the backbone of all lipid molecules?

carbon, hydrogen, and oxygen

Which lipids are polar, neutral fats or phospholipids?


What is the function of lipids in the body?

Lipids are used in the body for energy and are stored in fat for future energy needs. Lipids also serve as chemical messengers in the form of some hormones

What element is found in all proteins that is not found in carbohydrates or lipids?


What are the building blocks for proteins

Amino acids

What is the name of the bond holding two amino acids together?

peptide bond

What is a peptide?

A peptide is a molecule consisting of two or more amino acids in which the carboxyl group of one acid is linked to the amino group of another

How does an enzyme work?

Enzymes speed up or catalyze chemical reactions without being destroyed or altered. Enzymes are specific to the reaction they catalyze and the substrates (the substances they act upon) they use

How does a nucleotide differ from a nucleic acid?

nucleotides are the building blocks of nucleic acids.

What three parts compose a nucleotide?

Nucleotides are composed of a nitrogenous base, a 5-carbon(pentose) sugar, and a phosphate group

How many nitrogenous bases are there?

There are 5 nitrogen bases: adenine(A), guanine(G), cytosine (C), uracil(U) ,and thymine (T)

Explain the structure of DNA?

DNA molecules consist of two parallel strands of nucleotides, A,G, C, and T. The strands are connected by hydrogen bonds between the nitrogenous bases. Each nitrogenous base can only hydrogen-bond with one specific nitrogenous base. Adenine can only bond with thymine (A, T), guanine can only bond with cytosine (G,C). The two strands of bonded nucleic acids twist around each other in a spiral called a DOUBLE HELIX. The order of the nucleotides is unique to each individual and is carried in every cell of the individual

Why is DNA important to life?

DNA is the molecule that contains all the instructions needed by the cell to build protein. These instructions determine the shape and function of every tissue in the body and therefor the shape and function of the living organism

How does an ATP molecule differ from a nucleotide?

ATP is and RNA nucleotide containing the nitrogen base adenine with two additional phosphate groups

How does an ATP molecule supply cell with energy to do work?

As a nutrient (ex., glucose) is catabolized, the energy created is stored in ATP molecules, ATP stores this energy in the bonds between phosphate groups. When these bonds are broken, the stored energy is released from the ATP molecule. To use the energy stored in ATP, enzymes must move the terminal phosphate group to another molecule. The receiving molecule is then all PHOSPHORYLATED and temporarily has energy to do the work. During this process the ATP molecule loses a phosphate group and become ADP. Another phosphate group can be used, resulting in the creation of a molecule of AMP. As more glucose and other nutrients are metabolized, phosphate groups are joined to AMP creating a renewed source of ATP