Biochemistry Part I Flashcards
Define
Matter
Any substance that occupies space and has mass
Define
Elements
A form of matter with specific chemical and physical properties
How many elements are there?
98 naturally occurring
118 known / stable
List
Most common elements in the body (6)
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus*
Sulfur*
List
Subatomic particles
Proton
Neutron
Electron
Properties of
Protons
Positive
Mass = 1 amu
In nucleus
Properties of
Neutrons
Neutral
Mass = 1 amu
In nucleus
Properties of
Electrons
Negative
Negligible mass
Surrounding nucleus
Adding or removing protons changes…
the element and the atomic number
Adding or removing neutrons changes…
mass of an atom;
creates different isotopes (forms) of an element
Adding or removing electrons changes…
the charge of the atom
Define
Atomic mass
Average mass of one mole of an element, which takes isotopes (which have different mass numbers) into account
FYI: You will NOT need to memorize atomic mass v. mass number
Define
Isotope
Different forms of an element with the same number of protons but different numbers of neutrons
Define
Electron orbital
“Shells” around a nucleus where electrons are likely to be found
2 in first
8 in second and third
Define
Valence shell
Outermost electron orbital in an atom
Define
Molecule
Chemical joining of two or more atoms
Define
Covalent bond
Sharing of electrons between atomic nuclei
Define
Polar covalent
A covalent bond where electrons are more likely to be found around one atom (which is more electronegative)
Define
Nonpolar covalent
A covalent bond where electrons are equally shared
What leads to the formation of an cation?
Cation (cat-eye-on) = positive ion
Occurs when an atom loses electrons
Most common in first two groups (columns) of periodic table
What leads to the formation of an anion?
Anion = Negative ion
Occurs when atoms take electrons to become stable
Why is water polar
Oxygen is electronegative, leading to the formation of polar covalent bonds between oxygen and two hydrogens. The bent shape means more electrons (negative) are at the oxygen end
Define
Polarity
Unequal distribution of charge in a molecule
Define
Polar molecules
Molecules with partial positive and negative regions Ex: Water
Define
Nonpolar molecules
Molecules with no partial positive and negative regions
Ex: Hydrocarbons
Define
Hydrophobic
“Water fearing”
Nonpolar; avoids water
Define
Hydrophilic
“Water loving”
Polar; dissolves in or attracts to water
Density of water
Liquid: Most dense due to hydrogen bonds pulling molecules closer together than in solid form
Solid: Less dense than liquid
Importance of water’s density as a solid
Ice floats
- Good for insulating bodies of water
- Prevents freezing / sinking of ice in bodies of water so that Earth is not a giant icecube
Define
Specific heat capacity
Energy needed to increase the temperature of a substance
Water’s specific heat capacity
Very high, which helps regulate temperature within organisms and near large bodies of water
Define
Heat of vaporization
Energy required to convert substance from liquid to gas
Water’s heat of vaporization
Very high, leading to evaporative cooling
Define
Solvent
A substance that dissolves other substances
Define
Solute
A substance that dissolves in another substance
Define
Universal solvent
Water can cause dissociation of all polar molecules
Define
Cohesion
Attraction of like molecules (ex: water attracted to water)
Define
Adhesion
Attraction of different molecules (ex: water attracted to glass)
Define
Surface tension
Water’s cohesion pulls molecules together with enough force to overcome droplets being flattened by gravity; some objects remain on the top of water
Define
pH
Measure of acidity or alkalinity (basicity)
Define
Acid
A substance that increases [H+] in solution pH < 7
Define
Base
A substance that increases [OH-] and/or decreases [H+] in solution pH > 7
Describe the
pH scale
14 - strongest base
>7 - base
7 - neutral
<7 - acid
1 - strongest acid*
Define
Buffer
A substance that prevents rapid change of pH in a solution
Define
Hydrocarbons
Chains of carbons and hydrogens
Define
Isomer
Any molecules with the same chemical formula but different arrangement of atoms
Define
Structural isomer
An isomer where the bonds are placed differently (ex: butane and isobutane)
Define
Geometric isomer
An isomer where the arrangement of atoms around double bonds differ
cis
Having functional groups and/or carbons that reside on the same side of a double bond
trans
Having functional groups and/or carbons that reside on opposite sides of a double bond
Define
Enantiomers
Mirror image isomers
Draw
Hydroxyl
Draw
Methyl
Draw
Carbonyl
Draw
Carboxyl
Draw
Amino
Draw
Phosphate
Draw
Sulfhydryl
List
Four types of macromolecules
Carbohydrates
Proteins
Lipids
Nucleic acids
Single units of macromolecules are called
monomers
Define
Polymer
Many connected monomers
What reactions make and break polymers?
Dehydration synthesis makes polymers
Hydrolysis breaks polymers
Energy in metabolic reactions
Making new bonds (forming polymers) requires energy
Breaking bonds (breaking down polymers) releases energy
