Chapter 2 - Chemical Level Flashcards
What is matter?
Anything that occupies space and has mass
What is chemistry?
The science of the structure and interactions of matter
What is mass?
Is the amount of matter in any object
Does not change
What is weight?
The force of gravity acting on matter
Does change
Matter exists in what three states?
- Solid - definite shape and volume
- Liquid- definite volume and assume the shape of its container
- Gas - neither definite shape nor volume
What are chemical elements?
Building blocks of all living and non living things.
Cannot be split into simpler substances by ordinary chemical means
What are the 4 major elements?
Oxygen (o), carbon (c), hydrogen (h), and nitrogen (n)
What are atoms?
The smallest unit of matter that retains the properties and characteristics of the element
(Each element is made up of atoms)
What is the nucleus of an atom?
The dense central core of the atom.
A subatomic particle.
What is the nucleus made of (in atoms)?
- Neutrons - no charge
2. Protons - positive charge
What are electrons?
Tiny, negatively charged particles that float around the nucleus, do not follow a fixed path or orbit but form a “cloud”
How many electrons can each shell house?
First shell - 2
Second shell - 8
Third shell - 18
18 in each shell after that.
An atom has the same number of what?
Protons (+) and electrons (-)
Which means that it doesn’t have an electrical charge, each atom is neutral.
What determines an atoms atomic number?
Number of protons
What is the mass number?
Sum of its protons and neutrons.
Example: sodium has 11 protons and 12 neutrons, therefore the mass number is 23
What is an isotope?
Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.
They have the same chemical properties because they have the same number of protons and electrons.
What is a radioactive isotope?
Some isotopes are unstable; their nuclei decay (spontaneously change) into a stable condition.
As they decay, they emit radiation
What is half-life?
The time required for an isotope for half of the radioactive atoms in the sample of that isotope to decay into a more stable form.
What is the standard unit of measurement for measuring the mass of atoms?
Daltons (atomic mass unit, amu)
What is the atomic mass or atomic weight?
The average mass of all of its naturally occurring isotopes
What is an ion?
Is an atom that has a positive or negative charge b/c it has an unequal number of protons and electrons
What is ionization?
The process of giving up or gaining electrons
What is a molecule?
A combination of two or more atoms sharing electrons
What is a compound?
A substance that contains atoms of two or more different elements, examples: water, sodium chloride
The molecule of oxygen is NOT a compound because it only has one element
What is a free radical?
An atom or a group of atoms with an unpaired electron in the outermost shell
Highly unstable, highly reactive and destructive to nearby molecules
May break apart important body molecules
What are chemical bonds?
The force that holds together the atoms of a molecule or a compound
What is the valence shell?
The outermost shell
What determines whether or not an atom will form a chemical bond?
The number of electrons in its valence shell.
8 - is stable, will not bond
7 - bonds easily, room for one electron
What is the octet rule?
One atom is more likely to interact with another if doing so leaves both with 8 valence electrons
What are the three kinds of chemical bonds?
- Ionic bonds
- Covalent bonds
- Hydrogen bonds
What is an ionic bond?
The force of attraction that hold together ions with opposite charges is an ionic bond.
What is a cation?
A positively charged ion
What is an anion?
A negatively charged ion
What is an electrolyte?
An ionic compound that breaks apart into positive and negative ions in a solution
What is a covalent bond?
Forms when two or more atoms SHARE electrons.
By sharing 1, 2, or 3 valence electrons
More sharing = stronger bond
(Rather than gaining or losing them)
What is a single covalent bond?
When two atoms share one electron pair
What is a double covalent bond?
When two atoms share two pairs of electrons
What is a triple covalent bond?
When two atoms share three pairs of electrons
What is a non-polar covalent bond?
Two atoms share electrons equally
Bonds between two identical atoms are always non-polar
What is a polar covalent bond?
The sharing of electrons between two atoms UNEQUALLY
The nucleus of one atom attracts the shared electrons more strongly than the nucleus from the other atom
Partial negative charge, partial positive charge.
(Water!)
What are hydrogen bonds?
Forms when a hydrogen atom with a partial positive charge attracts the partial negative change of electronegative atoms, most often oxygen or nitrogen.
Cannot bind atoms into molecules, not very strong
What is cohesion?
The tendency of like particles to stay together
Cohesion of water gives for a very high surface tension
What is a chemical reaction?
Occurs when new bonds form or old bonds break between atoms
Total mass of reactants must equal that of products
What are reactants?
The starting substances in a chemical reaction
What are the products?
The ending substances of a chemical reaction
What is metabolism?
All the chemical reactions occurring in the body
What are the three different kinds of energy? Describe them.
- Potential energy - energy stored by matter due to its position
- Kinetic energy - energy associated with matter in motion
- Chemical energy - a form of potential energy that is stored in the bonds of compounds and molecules
What is the law of conservation of energy?
Energy can neither be created or destroyed, it may be converted from one form to another.
What are exergonic reactions?
Release more energy than they absorb
What are endergonic reactions?
Absorb more energy than they release
What is activation energy?
The collision energy needed to break the chemical bonds of the reactants
What two things influence the chance that a collision will occur and cause a chemical reaction?
- Concentration - more particles, greater chance
2. Temperature - higher temp, particles move more, greater chance
What is a catalyst, what does it do?
Chemical compounds that speed up chemical reactions by lowering the activation energy needed for the reaction to occur.
Most important catalysts in the body are enzymes.
What are synthesis reactions?
When two or more atoms, ions, or molecules combine to form new and larger molecules.
What is anabolism?
Anabolic reactions are usually endergonic b/c they absorb more energy than they release.
All synthesis electrons that occur in your body are referred to as anabolism.
What are decomposition reactions?
Reactions that split up large molecules into smaller atoms, ions, molecules.
What is catabolism?
The decomposition reactions that occur in your body are referred to as catabolism.
Usually exergonic b/c they release more energy than they absorb.
What are exchange reactions?
They consist of both synthesis and decomposition reactions.
AB + CD –> AD + BC
What are reversible reactions?
The products can revert to the original reactants
What are oxidation-reduction reactions?
They are essential to life
The reactions that break down food molecules to produce energy
Are always parallel, oxidation and reduction occur together
What is oxidation?
Refers to the loss of electrons, and in the process the oxidized substance releases energy
What is reduction?
Refers to the gain of electrons, in the process the reduced substance gains energy
What are the two principal classes of compounds?
Inorganic and organic
What makes inorganic compounds different?
They usually lack carbon (C) and are structurally simple
Molecules only have a few atoms and cannot be used by cells to perform complicated biological functions
What is special about organic compounds?
Always contain carbon, usually contain hydrogen and always have covalent bonds
Most are large molecules, made up of long chains of carbon atoms
What is the most important inorganic compound?
Water
What is the most important property of water?
It’s polarity - the uneven sharing of valence electrons that confers a partial negative charge near the oxygen and a partial positive charge near the hydrogen
Makes water an excellent solvent
Allows water to resist temperature changes
What is a solvent?
The solvent dissolves another substance called the solute
What does hydrophilic mean?
Solutes that are charged or contain polar covalent bonds are hydrophilic, which means they dissolve easily in water (sugar, salt)
What does hydrophobic mean?
Molecules that contain mainly nonpolar covalent bonds
They are not very water soluble (fats or oils)
What is hydrolysis?
Decomposition reactions break down large molecules into smaller molecules by the addition of water molecules (in digestion)
What is a dehydration synthesis reaction?
Two smaller molecules join to form a larger molecule and a water molecule is one of the products formed
What is a mixture?
A combination of elements and compounds that are physically blended together but not bound by chemical bonds
What is a colloid?
The solute particles are large enough to scatter light, usually appear translucent or opaque
The solutes in solutions and colloids do not separate from the solvent
What is a suspension?
The suspended material may mix with the liquid or suspending medium for some time, but eventually it will settle out (blood)
How can concentration be expressed?
By mass per volume percentage
Units of moles per litre (total number of molecules per in a given volume)
What is a mole?
The amount of any substance that has a mass in grams equal to the the sum of the atomic masses of all its atoms
What happens when inorganic acids, bases or salts dissolve in water?
They dissociate - they separate into ions and become surrounded by water
What is an acid?
Is a substance that dissociates into one or more hydrogen ions (H+) and one or more anions, b/c H+ is a single proton with one positive charge, an acid is referred to as a proton donor.
What is a base?
Removes H+ from a solution and therefore is a proton acceptor
Many bases dissociate into one or more hydroxide ions (OH-) and one or more cations
What is a salt?
Dissociates into cations and anions, neither of which is H+ or OH-
What makes a solution acidic?
More H+ dissolved in the solution
What makes a solution more basic?
More OH- dissolved in the solution
What is the pH scale?
A solutions acidity or alkalinity is expressed from 0-14
Based on the concentration of H+ in the solution
Midpoint is 7
What does a pH of 4 mean?
Acidic
What does a pH of 8 mean?
Basic
What is the pH of blood?
Between 7.35 and 7.45
What is the function of buffer systems?
To convert strong acids or bases to weak acids and bases
What are the main categories of organic compounds?
Carbohydrates, lipids, proteins, nucleic acids, and adenosine triphosphate (ATP)
What makes carbon useful to living organisms?
Can form bonds with one to thousands of other carbon atoms to produce large molecules
The body can build many different organic compounds, each with a unique structure and function
Useful for body building structures
Do not dissolve easily in water
What kind of bond holds together organic compounds?
Covalent bonds
What is a carbon skeleton?
A chain of carbon atoms
What is a hydrocarbon?
A carbon atom bonded with a hydrogen atom
What are the different kinds of functional groups of organic molecules?
- hydroxyl, alcohols can an OH- group which is polar
- sulfhydryl, thiols have an SH group which is polar
- carbonyl, ketones contain a carbonyl group within the carbon skeleton, polar
- carboxyl, carboxylic acids contain a carboxyl group at the end
- ester, esters predominate fats and oils
- phosphate, contain a phosphate group very hydrophilic
- amino, amines have an NH2 group which can act as a base
What are macromolecules?
Very large molecules
What is a polymer?
Is a large molecule formed by the covalent bonding of many identical or similar small building block molecules called monomers
What is an isomer?
Molecules that have the same molecular formation but different structures
What do carbohydrates include?
Sugars, glycogen, starches, and cellulose
What is the main function of carbohydrates?
Source of chemical energy for generating ATP needed to drive metabolic reactions
What are the elements found in carbohydrates?
Carbon, hydrogen and oxygen
What are the three main groups of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
What two things are knows as simple sugars?
Monosaccharides and disaccharides
What is a monosaccharide?
Simple sugar that contains 3-7 carbon atoms
Glucose, fructose, deoxyribose, ribose
What is a disaccharide?
Simple sugars formed from the combination of two monosaccharides by dehydration synthesis
Sucrose, lactose, maltose
What are polysaccharides?
From tens to hundreds of monosaccharides joined by dehydration synthesis
Glycogen, starch, cellulose
Insoluble in water, do not taste sweet
What are lipids? What elements are they made of?
Fats
Contain carbon, hydrogen and oxygen
How are lipids different from carbohydrates?
They do not have a 2:1 ratio of hydrogen to oxygen
There are fewer polar covalent bonds
Most lipids are insoluble
Hydrophobic
What are lipoproteins?
To become more soluble in blood, lipids join with hydrophilic protein molecules
Are soluble, b/c proteins are on the outside and lipids are on the inside
What are the different types of lipids called?
Fatty acids Triglycerides Phospholipids Steroids Eicosanoids Lipoproteins
What is the function of fatty acids?
Used to synthesize triglycerides and phospholipids or catabolized to generate ATP
Consists of a carboxyl group and a hydrocarbon chain
What is the function of triglycerides?
Protection, insulator , energy storage
Consists of a single glycerol molecule and three fatty acid molecules
What is the function of phospholipids?
Major lipid component of cell membranes
What is a saturated fatty acid?
Contains only single covalent bonds between the carbon atoms of the hydrocarbon chain, SATURATED with hydrogen atoms
What is an unsaturated fatty acid?
Contains one or more double covalent bonds between the carbon atoms of the hydrocarbon chain
What forms the backbone of the triglyceride?
A three carbon glycerol molecule
What is an ester linkage?
The chemical bond formed where each water molecule is removed from the joining of a glycerol molecule and a fatty acid molecule (3x)
What is a fat?
A triglyceride that is solid at room temperature
Mostly saturated
What is an oil?
A triglyceride that is liquid at room temperature
Mostly unsaturated
What is the most highly concentrated form of energy in the body?
Triglycerides
What are essential fatty acids?
Cannot be made by humans, must be obtained by diet
Omega-3 and omega-6
How are phospholipids different from triglycerides?
Glycerol backbone with only 2 fatty acid chains attached and a phosphate group (with a nitrogen head)
The head is polar and can form hydrogen bonds with water
The tail is nonpolar and can interact only with other lipids
What does amphipathic mean?
Molecules that have both polar and non-polar parts
What is a steroid?
Have 4 carbon rings
Body cells synthesize other steroids from cholesterol (large nonpolar region and a hydrocarbon tail)
Commonly known as -sterols b/c they have at least one hydroxyl group (OH-)
What are eicosanoids?
Lipids derived from a 20-carbon fatty acid called arachidonic acid
What are proteins?
Are large molecules that contain carbon, hydrogen, oxygen and nitrogen
May contain sulphur as well
Much more complex than carbohydrates or lipids
What are enzymes?
Proteins that speed up most biochemical reactions
What are antibodies?
Proteins that defend against invading microbes
What are the different functions of proteins?
Structural - framework for body Regulatory - hormones Contractile - allow shortening of muscle cells, which produces movement Immunological - antibodies Transport - hemoglobin Catalytic - enzymes
What are amino acids?
Monomers of proteins
20 different amino acids
Each has a hydrogen atom and three important functional groups attached to a central carbon atom
What are the three functional groups amino acids?
- an amino group (NH2)
- an acidic carboxyl group (COOH)
- a side chain (R group)
What is a peptide bond?
The covalent bond joining each pair of amino acids
As a peptide bond is formed, a water molecule is removed
In an amino acid, what is the minimum number of carbon atoms? Nitrogen atoms?
2 carbon, 1 nitrogen
What are the 4 structures of proteins?
- Primary - amino acid sequence
- Secondary - twisting and folding due to hydrogen bonds
- Tertiary - three dimensional shape of polypeptide chain
- Quaternary - arrangement of two or more polypeptide chains
What are fibrous proteins?
Insoluble in water and their polypeptide chains form long strands that are parallel to each other, structural functions
What are globular proteins?
More or less soluble in water and their polypeptide chains are spherical, metabolic functions
What is denaturation?
If a protein loses its shape, it is no longer functional
What are enzymes?
Protein molecules that are catalysts
Highly specific - each enzyme binds to a particular substrate
Highly efficient at catalyzing reactions
Subject to a variety of cellular controls
What are nucleic acids and what are the two different kinds?
Huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen and phosphorus
- DNA - deoxyribonucleic acid, inherited gene material in humans
- RNA - ribonucleic acid, relays instructions to genes to synthesize proteins for amino acids
What is a nucleotide?
A nucleic acid is a chain of repeating monomers called nucleotides
Forms the basis of DNA
Each nucleotide of DNA consists of what three parts?
- Nitrogenous base (A, T, C, G)
- Pentose sugar (5 carbon sugar)
- Phosphate group - form the backbone of DNA strand
What do each of the bases pair with?
A-T
C-G
What are the names of the 4 DNA bases?
Adenine
Thymine
Cytosine
Guanine
What is a mutation?
Any change that occurs in the base sequence of a DNA strand
How is RNA different from DNA?
RNA is a pentose ribose, RNA contains U (uracil) instead of thymine
What are the three different kinds of RNA?
Messenger RNA
Ribosomal RNA
Transfer RNA
What is ATP?
Adenosine triphosphate is the “energy currency” of living systems
Transfers energy freed in exergonic catabolic reactions to power cellular activities that require energy
(Movement, cellular division)
Describe the chemical reaction of ATP.
ATP + water –> ADP (adenosine diphosphate) + phosphate group + energy
Describe the two phases of cellular respiration.
- Anaerobic phase - does not require oxygen, glucose is broken down by a series of catabolic reactions into pyruvic acid. Each glucose molecule that is converted into pyruvic acid yields two molecules of ATP
- Aerobic phase - needs oxygen! Glucose is completely broken down into carbon dioxide and water. These reactions generate heat and 36 or 38 ATP molecules
