Module 2: Intro To Chemistry Flashcards
Chemistry is the science of the structure and interactions of matter, which is anything that occupies space and has mass
Describe the structure of an atom
Units of matter of all chemical element consist of a nucleus (positively charged protons and neutral neutrons) and negatively charged electrons that move about the nucleus in different energy levels.
Define the term isotope
Different atoms of the same chemical element that have the same number of protons but different numbers of neutrons. A radioactive isotope is unstable and emits radiation (energy).
Define ion
If an atom either gives up or gains electrons it becomes an ion. Which is an atom that has a positive or negative charge due to its unequal number of protons and electrons.
Define molecule
When 2 or more atoms share electrons, the resulting combination is called a molecule
Define compound
The combination of 2 or more different atoms. Ie: water=H2O
Define a free radical
An electrically charged atom or group of atoms with an unpaired electron in its outermost shell. Free radicals become stable by either giving up their unpaired electron or by taking on an electron from another molecule
Define an antioxidant
Substances that inactivate oxygen - derived free radicals
The atoms of a molecule are held together by forces of attraction called chemical bonds. Describe the different types of chemical bonds.
Ionic bonds, covalent bonds and hydrogen bonds
Describe an ionic bond
When an atom loses or gains a valence electron, ions are formed. Positively and negatively charged ions are attracted to one another. When this force of attraction holds ions of opposite charges together, an ionic bond results.
What are cations?
Positively charged ions. Anions are negatively charged ions.
Ionic bonds are _______ than covalent bonds but ______ than hydrogen bonds.
Weaker, stronger
Ionic compounds exist as solids but in solution some may dissasociate into positive and negative ions. Such a compound is called an ____.
Electrolyte
What are covalent bonds and how are they formed?
When the atoms of molecules share electrons. Covalent bonds are the most common chemical bonds in the body. Covalent bonds can be nonpolar or polar.
Covalent bonds are the ____ bonds.
Strongest
The polar covalent bonding of hydrogen to oxygen or nitrogen allows for ____ bonds to form.
Hydrogen
What are hydrogen bonds?
2 other atoms (usually oxygen or nitrogen) associate with a hydrogen atom
_____ bonds are weak and cannot bind atoms into molecules; instead, these bonds serve as links between molecules to provide strength to help determine the 3 dimensional shape of large molecules.
Hydrogen bonds
How does a chemical reaction occur?
When new binds are formed or old bonds break between atoms
The starting substance of a chemical reaction are known as the ____. The ending substances of a chemical reaction are the _____.
Reactants, products
What is the law of conservation of mass?
The total mass of the reactants equals the total mass of the products
____ refers to all the chemical reactions occurring in an organism.
Metabolism
Energy is the capacity to do work. Describe the different forms of energy.
Potential energy, chemical energy and kinetic energy
What is potential energy?
The energy stored by matter due to its position (ball at top of hill)
What is chemical energy?
A form of potential energy stored in the bonds of compounds or molecules.
What is kinetic energy?
The energy associated with matter in motion.
Describe the types of chemical reactions
Synthesis reaction, decomposition reaction, oxidation and reduction
What is a synthesis reaction?
Occurs when 2 or more atoms, ions or molecules combine to form new and larger molecules. The reactions are anabolic which means that bonds are formed.
Describe a decomposition reaction.
A molecule is broken down into smaller parts. These reactions are catabolic which means that chemical bonds are broken in the process.
In oxidation-reduction, electrons are taken from the atom being oxidized by the atom being reduced. What is oxidation?
The loss of electrons from a molecule, which results in a decrease in the potential energy of the molecule.
What is reduction?
The gain of electrons by a molecule which results in an increase in the potential energy of the molecule.
Differentiate between organic and inorganic compounds.
Inorganic compounds usually lack carbon and are simple molecules; whereas organic compounds always contain carbon and hydrogen, always have covalent bonds and usually contain oxygen.
Discuss the properties of water
The most important and abundant inorganic compound. Water enables reactants to collide to form products. Water dissolves wastes. A major part of mucus and lubricating fluids. Water has a high heat capacity.
The most important property of water is its polarity. Describe what that means.
In the water molecule the uneven sharing of valence electrons confers a partial negative charge near the single oxygen atom and two partial positive charges near the two hydrogen atoms.
Describe hydrolysis
Breaks large molecules down into simpler ones by adding a molecule of water.
What is dehydration synthesis?
Occurs when 2 simple molecules join together, eliminating a molecule of water in the process.
When the molecules of inorganic acids, bases or salts dissolve in water, they undergo ____ or ____, meaning that they separate into ions.
Ionization, dissociation
What is an acid?
Acids ionize into 1 or more hydrogen ions (H+) and one or more anions (negative ions).
What is a base?
Bases dissociate into 1 or more hydroxide ions (OH-) and 1 or more cations (positive ions). Bases are proton acceptors.
When dissolved in water, a salt _____ into cations and anions, neither of which is He+ or OH-
Dissociates
Define pH
The acidity or alkalinity of a solution is based on the pH scale which runs from 0-14. Values below 7 indicate acid solutions. Values above 7 indicate alkaline solutions.
Define the importance of buffers and the function of a buffer systems (BS)
The pH values of different parts of the body are maintained at a fairly constant level by buffer systems which usually consist of a weak base and a weak acid. BS is to convert strong acids into weak acids or bases (carbonic-acid-bicarbonate buffer system).
What is the pH of distilled water?
7.0
What is the pH of urine?
4.6 - 8.0
What is the pH of saliva?
6.35 - 6.85
What is the pH of blood?
7.35 - 7.45
List the subcategories or carbohydrates
Monosaccharides, disaccharides and polysaccharides
Carbohydrates provide most of the energy needed for life, what do they include?
Sugars, starches, glycogen and cellulose
How are monosaccharides and disaccharides (simple sugars) formed?
Disaccharides are formed from 2 monosaccharides by dehydration synthesis. Hydrolysis can be used to split disaccharides back into simple sugars.
Describe polysaccharides and name the principal polysaccharide in the human body.
The largest carbohydrates, are known as complex carbohydrates; they can include hundreds of monosaccharides. Glycogen is stored in the liver or skeletal muscles.
Identify and describe lipids and their subclasses
Lipids, like carbs, contain carbon, hydrogen, and oxygen. However they do NOT have a 2:1 ratio of hydrogen to oxygen. Triglycerides, phospholipids, and steroids.
Describe triglycerides
The most plentiful lipids in the body and provide protection, insulation and energy (both immediate and stored).
Describe phospholipids
Are structurally similar to triglycerides and are i.portant membrane components.
Describe steroids
Are composed of 4 rings of carbon atoms. Ie: dietary lipid cholesterol and the sex hormones estrogen and testosterone.
Describe the structure of amino acids
Contain carbon, hydrogen, oxygen, and nitrogen. They are joined together in a step-wise fashion with each covalent bond joining one amino acid to the next, which forms a peptide bond.
Describe the functions of proteins
The give structure to the body, regulate processes, provide protection, help muscles to contract, transport substances and serve as enzymes.
Analysts in living cells are called enzymes. Discuss the structure and function of enzymes.
Extremely efficient with respect to the number of substrate molecules with which they react. They speed up chemical reactions by increasing the frequency of molecule collisions, lowering the activation energy and properly orienting colliding molecules.
Discuss the structure and function of nucleic acid (DNA and RNA)
Nucleic acids are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen and phosphorus.
Describe deoxyribonucleic acid (DNA)
Forms the genetic code inside each cell and thus regulates most of the activities that occur in our cells throughout our lifetime.
Describe ribonucleic acid (RNA)
Carries instructions from the genes in the nucleus of the cell to guide how the ribosomes assemble amino acids into proteins.
What are nucleotides?
The basic units if nucleic acids which are composed of a nitrogenous base, a pentose sugar, and a phosphate group.
Discuss the structure and function of adenosine triphosphate (ATP)
ATP is the principal energy storing molecule in the body. It consists of 3 groups attached to an adenosine unit which is composed of adenine and the 5 carbon sugar ribose.
What happens when energy is liberated from ATP?
It is decomposed to adenine diphosphate (ADP) and phosphorus (P).
Adenosine triphosphate is manufactured from what?
ADP adenosine triphosphate and P phosphorous using the energy supplies by various decomposition reactions, particularly that of glucose.
What is a radioactive isotope?
An isotope that is unstable and emits radiation as it breaks down.
What are the 4 chemical groups of an amino acid?
Hydrogen, amine, carboxyl and side chain (R group)
Discuss enzyme function
Enzymes are biological catalysts that have specific “active” binding rates for certain substrates. Enzymes lower the energy of activation so that reactions in the cell can occur at appropriate rates.
Define the term acid
When put in water an acid is a substance that dissociates into hydrogen ions and one or more anions.
Define the meaning of the term pH
A measure of the hydrogen ion concentration of a solution
List the 4 elements that make up about 96% of our body weight
Carbon, hydrogen, oxygen, nitrogen
What is a covalent bond? Example
A covalent bond is a strong bond between atom in which they share one of more electrons. Water is an example of covalent bonding
Describe hydrogen bonds and give 2 examples of their importance in cells.
Extremely weak bonds between 2 atoms. They are important for giving proteins and enzymes their 3 dimensional shapes, bonding specialized molecules such as hormones and receptors, and binding enzymes to substrates.
Diagram and label the structures of a typical atom.
Proton P+
Nucleus: Neutrons No
Electrons E-
How does RNA differ from DNA chemically and physically?
RNA nucleotides are made up of the sugar ribose, dna nucleotides are made up of deoxyribose. RNA is usually a single stranded molecule (dna is double). RNA uses the nitrogenous base uracil vs thymine in DNA.
What is an ionic bond? Give an example
A weak bonds between 2 oppositely charged ions. The bond breaks when the molecule is placed in water. Ex sodium chloride (table salt).
How is ATP the energy currency of the cell?
ATP releases energy stored in its 2 high energy phosphate bonds.
What is a buffer?
A combination of chemicals that minimizes changes in the pH of a solution when acids or bases are added.
Identify the monosaccharides and give 3 common examples
Monosaccharides are the simple sugars made up of carbon, hydrogen and oxygen. Ex glucose, fructose and deoxyribose.
What are nucleotides?
The building blocks of nucleic acids. Nucleotides are made up of a nitrogen base, a pentose sugar and one or more phosphate groups.
Define the term salt and give an example
When put in water, a substance that dissociates into cations and anions neither of which is H+ or OH-. Ex salt is sodium chloride
List 4 functions of water that make it useful in the body
Water is a good solvent. It participates in chemical reactions vital to cells. Water absorbs heat without significantly changing temperature. Water acts as a lubricant.
What is an isotope?
Atoms of the same element that differ slightly in mass. Different isotopes of the same element have the same number of protons but more or less neutrons.
What kind of net charge is carried by a cation?
A cation is a positively charged ion.
Describe the structure of DNA
DNA is a large molecules consisting of 2 helically wound chains of nucleotides. The 2 chains are held together by hydrogen bonding between the nitrogenous base pairs; adenine and thymine, cytosine and guanine.
All living and nonliving things consist of ____.
Matter
Define the term base
When put in water, a base is a substance that dissociates into hydroxyl OH- ions and 1 or more cations. A base can be described as having the capacity to pick up one or more hydrogen H+ ions.
Define the term lipid
Lipids include most of the substances that are insoluble in water but soluble in non-polar solvents such as chloroform or ether
What is an electrolyte?
A substance such as salt, an acid or a base that when put in water dissociates or ionized into ions. In solution, electrolytes conduct an electric current.
Identify 3 important types of lipids and their functions:
Triglycerides - energy storage.
Phospholipids - membrane structure.
Steroids - hormones membrane structure.
