Chapter 2: The Chemical Level of Organization Flashcards
List the main chemical elements of the human body
The science of the structure and interactions of matter
Chemistry
Matter
Anything that occupies space and has mass; made up of chemical elements
Mass
The amount of matter in any object, which does not change
Weight
The force of gravity acting on matter; this can change
Three states of matter
solids, liquids and gas
Chemical Elements
Make up all forms of matter, living and non-living.
There are 118; 92 are naturally occuring
How many chemical elements are normally present in your body?
26
Name the 4 major elements that constitute approximately 96% of the body’s mass
oxygen (O)
carbon (C)
hydrogen (H)
nitrogen (N)
Name the 8 lesser elements that contribute to about 3.6% of the body’s mass
Carla Plays Poker So She Can Make Ingenious <wins></wins>
Calcium (Ca)
Phosphorus (P)
Potassium (K)
Sulfur (S)
Sodium (Na)
Chloride (Cl)
Magnesium (Mg)
Iron (Fe)
What is the term for the remaining elements that make up 0.4% of body mass
Trace Elements
Eg Iodine
Three categories of elements
- Major Elements
- Lesser Elements
- Trace Elements
The smallest units of matter that retain the properties and characteristics of an element
Atom
These make up atoms
Subatomic Particles
3 types of subatomic particles
Proton, neutron, and electrons
Nucleus of an atom
The dense central core
Where are protons, p+, and neutrons, N0, found within the atom
The nucleus
Where are electrons, e-, found in an atom?
How do they move?
They move about in a space surrounding the nucleus
Form a ‘cloud’ around the nucleus and do not move in a fixed pathway
Certain regions around the nucleus that specific groups of electrons are most likely to move about within. Each one of these can hold a specific number of electrons.
Electron Shells
How many electrons does each electron shell hold?
First (closest to nucleus) = max 2
Second = max of 8
Third = max 18
Atomic Number
The number of protons within an atoms nucleus
Mass Number
The sum of an atoms protons and neutrons
Sodium has 11 protons and 12 neutrons, what is it’s atomic number and it’s mass number?
Atomic number is 11
Mass number is 23
Isotopes
Atoms of an element that have different numbers of neutrons and therefore different mass numbers
Identical chemical properties because they have the same number of electrons
Radioactive Isotopes
Unstable isotopes; these atoms have a nuclei that will decay to a stable configuration and will emit radiation (either subatomic particles or packets of energy) and often will turn into a different element
The time required for half of the radioactive atoms in a sample of an isotope to decay into a more stable form
Half-life
Atomic Mass
The average mass of all of an elements naturally occuring isotopes; usually close to most abundant isotope
Ion
An atom that has a positive or negative charge because it has unequal numbers of protons and electrons
Ionization
The process of giving up or gaining electrons
Molecule
When two or more atoms share electrons
Compound
A substance that ocntains atoms of two or more different elements
Free Radical
An atom of group of atoms with an unpaired electron in it’s outermost shel
Makes it unstable, highly reactive and destructive to nearby molecules
The forces that hold together the atoms of a molecule or compound
Chemical Bonds
Valence Shell
An atoms outer most shell; likelihood of chemical bonds occuring depends on the number of electrons in this shell
Octet Rule
One atom is more likely to interact with another atom if doing so will leave both with eight valence electrons; can donate, take or share electrons
Name three types of chemical bonds
Ionic
Covalent
Hydrogen
Positive and negative charged ions are attracted to one another and can create this type of chemical bond
Ionic Bonds
Cation
A positively charged ion (loses electrons and therefore has more protons)
Anion
A negatively charged ion (gains electrons and therefor has more electrons)
Electrolyte
An ionic compound that breaks apart into positive and negative ions in solution
When two or more atoms share electrons rather than gaining or losing them, a _________________ bond is formed. The more electrons shared between them, the stronger the bond
Covalent Bond
- most common bond in the human body
- can be the between atoms of same or different elements
Covalent bond numbers
Single - one pair shared
Double = two pairs shared
Triple E three pairs shared
Nonpolar Covalent bonds
when two atoms share the electrons equally, eg between two atoms of same element
Polar covalent bond
Sharing of electrons is unequal, the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom
Electronegativity
When polar covalent bond forms, the atom with the stronger pull on the electrons has a partial negative charge and has greater electronegativity
An important polar covalent bond in living systems
H20 The bond between hydrogen and oxygen
Polar covalent bonds that form between hydrogen atoms and other atoms
Hydrogen Bonds
How does a hydrogen bond form?
When a hydrogen atom with a partial positive charge attracts the partial negative charge of neighboring electronegative atoms
What type of bond forms because of attraction of oppositely charged PARTS of molecules rather than sharing of electrons or donating/taking electrons
Hydrogen Bonds
Bond that cannot bind atoms into molecules; weakest bond;
Hydrogen Bonds
Surface Tension
Caused by hydrogen bonds of water molecules and measures the difficulty of stretching or breaking the surface of a liquid
Chemical Reaction
When new bonds form or old bonds break between atoms; interactions of valence electrons are basis of all chemical reactions; involves energy changes
Metabolism
All chemical reactions occuring in the body
Reactants
Starting substances
Products
ending substances
What are the two principle forms of energy?
Potential and kinetic
Potential Energy
Energy stored by matter due to its position
Kinetic Energy
The energy associated with matter in motion
Law of conservation of energy
Total amount of energy remains the same; it cannot be created nor destroyed, but can be converted from one form to another
Chemical Energy
a form of potential energy that is stored in the bonds of compounds and molecules
Exergonic Reaction
A chemical reaction that releases more energy than is absorbed
Endergonic Reaction
A chemical reaction where more energy is absorbed than is released.
Activation energy
The collision energy needed to break the chemical bonds of a reactant; needed to start a reaction because it causes enough energy to be absorbed that their chemical bonds become unstable and new combinations begin to be formed
The more particles of matter present in a confined space, the greater the chance they will collide
Concentration affects reactions
As temperature increases, the particles of matter move more rapidly, increasing likeliness of more forceful collisions and therefore more likely the collision will produce a reaction
Temperature affects reactions
Chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur. Eg enzymes
A catalyst
Synthesis Reactions - Anabolism
When two or more atoms, ions or molecules combine to form new or larger molecules. Usually energonic.
Decomposition Reactions - Catabolism
Split up larder molecules into smaller atoms, ions or molecules. Usually exergonic.
Exchange reactions
Reactions that consist of both synthesis and decomposition reactions
Reversible reactions
the products of a reaction can revert to the original reactants (indicated by two half hours pointing in opposite directions)
Oxidation-Reduction Reactions
Important in breaking down food molecules and producing energy
Oxidation - loss of electrons where oxidized substance releases energy
Reduction - gain of electrons, the reduced substance gains energy
Compounds that usually lack carbon and are structurally simple. Eg water, salts, etc. ionic or covalent bonds.
Inorganic compounds
What percentage of a lean human body does water make up?
55-60%
Other inorganic matter makes up about 1-2%
Inorganic compounds that contain carbon are:
Carbon Dioxide
Bicarbonate
Carbonic Acid
Compounds that always contain carbon, usually contain hydrogen and always have covalent bonds
Organic Compounds