biochemistry. what are the main parts of an atom? essential question
TRANSCRIPT
Matter:
All living things are made of matter. Matter is anything that has mass and takes up space.
• Properties– physical property
• description of shape, mass, volume• melting point, boiling point
– chemical property• structure of molecules which make up
substance• how substance reacts with another
Matter
• Elements
– element
• a substance that can not be broken down into a simpler substance
– 25/90 elements are essential to life
• CHNOPS – 6 greatest
• You must know the symbols
Matter
• atom
– smallest particle of an element that has the characteristics of that element
Biochemistry
Atoms
• atom structure
– nucleus
• center, contains neutrons & protons
– neutrons
– carries no charge,
neutral = n0
– protons
• carries a positive charge
= p+
Atoms
• atom structure
– electron
• electrons orbit nucleus in separate energy levels or clouds– 1st shell= 2 electrons– 2nd shell= 8 electrons– 3rd shell= 18 electrons– 4th shell= 32
• Keep in mind that not each shell must be full before moving to the next level
Biochemistry
Atoms• periodic table
2
He
Helium
4.002602
The atomic number tells us the # of protons. It is unique to each atom. How do we determine the number of electrons?
The mass number tells us the # of protons + neutrons.
How do we determine the number of neutrons?
Compounds
• Compounds are substances composed of atoms of 2 or more different elements that are chemically combined
• Uses molecular formula to designate– NaCl
– H2O
(the properties of a compound are different from those of its individual elements)
• covalent bond
– atoms share electrons
ex: water, sugars, proteins
• ionic bond
– Electrons are transferred between atoms » An atom that has gained or lost an electron
(therefore, has a charge)
is known as an ion.
Chemical Reactions• Chemical Reactions occur when bonds
between atoms are formed or broken, causing substances to combine and recombine as different molecules.
• All of the chemical reactions that occur within an organism are referred to as that organism’s metabolism.
» H20 means 2 Hydrogen atoms for every 1 Oxygen atom. 5H20 means 5 molecules of water. How many atoms are in 5H20?
Mixtures and solutions
• mixture
– combination of substances in which individuals retain individual propertiesex: mixed sugar and sand,
oil and water
• solution– mixture of one or more solutes are evenly
distributed in a solvent
ex: salt in water
Mixtures and solutions
• solution
– solute
• substance which dissolves ex: sugar
– solvent
• holds dissolved substance ex: water
– the greater the solute = greater the concentration
Acids and bases• pH
– measure of how acidic or basic a solution is
• acid– forms hydrogen ions (H+) in water– pH below 7
• base– forms hydroxide ions (OH-) in water– pH above 7
pH scale ranges from 0 to 14 with acids below 7 and bases above 7.
–
How to Test for pH• 1. Litmus Paper: only if an acid or base
– Red and Blue paper– Red changes to Blue = Basic– Blue changes to Red = Acid
• 2. pH paper– Gives you an exact pH # by color change
• 3. Digital pH Meter– Gives a digital readout
Water
• polar molecule
– molecule with uneven distribution of charge
– water is polar, O atom pulls e-’s from H atoms
Water
• properties of water
– water resists temperature change
– water expands when it freezes
– cohesion
• water molecules attracted to each other
– adhesion
• water molecules attracted to sides of container
Biochemistry
Water & Diffusion
Diffusion » Brownian motion is the random,
erratic movement of particles.» Diffusion is the net movement of
particles from an area of higher concentration to an area of lower.
» What is the result of diffusion?
– monomer
• Small molecule that can be bound to other monomers to form polymers
– polymer
• larger molecule formed from smaller subunits
• Condensation forms polymers
• Hydrolysis breaks down polymers
Life Substances
• Substances that make up living things are known as organic compounds.
• Organic compounds always contain C and H, but often contain other elements such as O, N, P, S.
• Macromolecules
Enzymes
• Key terms & concepts– Enzyme– Biological catalyst– Substrate– Active Site– -ase– Proteins– Inhibitors– Denature– Activation energy– Enzyme/ substrate complex– Induced fit model/ lock and key
• enzyme
– increase rate of metabolic reactions
– induced fit (lock and key) mechanism
– They are proteins!
Reactions
– chemical equations
• 2H2 + O2 → 2H2O
• # of atoms on each side of reaction must be balanced
• coefficients must be balanced
__ C6H12O6 → C12H22O11 + H2O
Reactions
– chemical equations
• dehydration synthesis (condensation reaction)
– two subunits make polymer
– water is released
2C6H12O6 → C12H22O11 + H2O
Reactions
– chemical equations
• hydrolysis
– H2O splits bond
– two subunits created
– C12H22O11 + H2O → 2C6H12O6
Reactions
– enzymes
• lowers activation energy
• acts as catalysts, speeds up rate of reaction
• induced fit model (lock and key)
Reactions
– enzymes
• substrate
– changed after released by enzyme
• enzyme
– active site
» where substrate binds to enzyme
» can be used over and over