Chapter 2: The Chemistry Of Life Flashcards
Matter
Anything that has mass and occupies space
Element
A pure substance with unique physical and chemical properties
Can not be broken down into other substances
Atom
Smallest unit of an element
Protons, Neutrons, and Electrons
P = positive charge E = negative charge (floating around - orbit the nucleus in electron shells) N = lack an electrical charge
Atomic nucleus
If it is positively charges it contains one or more protons and usually the same number of neutrons
Different than cellular nucleus
Atomic number
Represents the number of protons in an atom
Atomic mass number
Total number of protons and neutrons in an atom (electrons don’t count when adding up mass)
If you change the protons…
Changes the type of element
If you change the neutrons…
Slightly changes the chemical properties
ISOTOPE
If you change the electrons…
Changes the overall atomic charge
Ions
Atoms of an element that carry a net charge
Combinations of atoms make…
Molecules
Can’t be of the same lament: O(2)
Biomolecules
Carbon based
Molecules found in living cells
Subset of organic molecules
Covalent bonds
Created by the sharing of electrons between constituent atoms
Strongest bond
Single bond exists when two atoms share a PAIR of electrons
Double bond exists with when two atoms share TWO PAIRS of electrons
Covalent bonds - polar vs non-polar
Polar = has a net electrical charge, if molecule contains oxygen or nitrogen combined with any other element (unequal sharing) Non-polar = no net electrical charge (equal sharing)
Ionic bonds
Weak bond
Not sharing - stealing of electrons
EX: Salt
Atoms or molecules that have gained or lost electrons and have a full unit of electrical charge are called ions
Water property: polar
A water molecule is 2 hydrogen atoms and one oxygen Aton held together by covalent bonds
Polarity of water is what gives water its unique properties
Water property: ice floats and acts as an insulator
Water molecules are farther apart in ice than in water, causing ice to be less dense and to float
Liquid has more molecules than ice
As water cools, the hydrogen bonds form in an orderly pattern
Water property: water is an excellent solvent
Things dissolve into it - like salt or sugar (these two things would be salutes)
Water inserts itself in polar molecules causing it to dissolve
Hydrophobic molecules are typically non-polar and do NOT associate with water
Hydrophilic molecules are polar and interact/form hydrogen bonds with water
Water property: water moderates temperature swings
Water can absorb and release large amounts of heat
High boiling point
High heat capacity of water in cells serves to protect them from changes in internal temperatures
Water property: the evaporation of water has a cooling effect
When water molecules are heated, they become energetic enough to escape their hydrogen bonds as water vapor in the process called evaporation
Water property: cohesion and adhesion
Cohesion: the hydrogen bonding between water molecules (molecules attracted to themselves) Creates surface tension
Adhesion: the hydrogen bonding between water and other molecules
The pH scale
Measures the concentration of hydrogen ions
1(strongly acidic) - 14 (strongly basic)
Acid releases hydrogen ions
Base accepts hydrogen ions
The higher the number on the pH scale, the fewer the number of protons in the solution
*Each number up or down is a difference of 10 times
Chemical reactions
Rearrangements of atoms
Breaking and forming bonds
Reactants > products
Atoms are never destroyed or created
Chemical reactions can be affected by…
PH
Temperature
Salt concentration
Organic molecules
Molecule that contains at least one carbon-hydrogen bond OR nitrogen-hydrogen bond
Biomolecules
Have a carbon framework
Monomers vocal entry one to each other to form polymers
They are polymers of carbon-based monomers
Biomolecules: Carbohydrates
AKA sugars or sac arises
Used for energy storage (glucose, sucrose) and structural support (cellulose in plants)
Monomer: monosaccharide - glucose and ribose
Polymer: polysaccharide - starch, cellulose, glycogen
Biomolecules: proteins
Functions: structure (hold cells together - collagen), transport (move molecules in a cell), cell signaling, enzymatic reactions
Monomer: amino acids (consist of a functional group attached to a R group)
Polymer: polypeptide/protein
Protein structure - folding
Primary: amino acids in a string
Secondary: bend that string and hold it in place with hydrogen bonds (beta-pleated sheet)
Tertiary: covalent and hydrogen bonds between portions that are far away from each other
Quarternary: more than one protein subunit bonded together - 2 tertiary structures together
Protein folding
Basic folded structure depends on sequence of amino acids
Denature get proteins
Destruction of a proteins 3D shape, resulting in a loss of protein activity/function
Things that effect it: pH, temperature, salt concentration
Biomolecules: lipids
Functions: long-term energy storage, plasma membrane, cell signaling (hormones)
Mostly hydrophobic/non-polar
Monomer: fatty acids (no polar hydrocarbon chains attached to a hydrophilic/polar head)
Polymer: fats/oils
Animals store surplus energy as…
Triglycerides - 3 fatty acid molecules bonded to a glycerol molecule
Saturated fatty acids
Fats
Solid at room temp
Butter
Unsaturated fatty acids
Liquid at room temp
Vegetable oils
Plants use these
Phospholipids
Make up cell membrane - phospholipid bilayer
They are 2 hydrophobic fatty acid tails (non-polar) bonded to hydrophilic heads (polar)
Biomolecules: Nucleic acids
Used for information storage and transformation, heredity, energy transfer
EX: DNA(double-stranded), RNA(single stranded)
Monomers: nucleotides (made up of a nitrogen base, sugar, and phosphate group)
Polymer: nucleus acids
