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NAME ________________________________________________________________ DATE _________________
Chapter 6: Chemistry in Biology
6.1 Atoms, Elements, & Compounds
Atoms
 Chemistry: ______________________________________________________________________
 Atoms: _________________________________________________________________________
 Made up of
 ___________________ (n0) in the _____________________
 ___________________ (p+) in the _______________________
 ___________________ (e-) orbiting around the __________________
 _________________ atoms have equal protons and electrons giving them an
overall charge of 0
 Atomic Number: number of _________________________ found in the
nucleus of the atom (therefore it is also the number of
_____________________ orbiting the ____________________)
 Atomic Mass: _____________________________________________________________________
 Isotopes: atoms of the _________________________________ with different numbers of
________________________ (so the atomic mass is different)
 Ion: an atom that has ______________________________ electrons
in order to achieve a full ________________________ shell, ions
carry a __________________
 If an atom _________________ an electron, it becomes more
_____________________ charged
 If it ___________ an electron, it becomes more
________________________________
Elements
 Element: _______________________________________________________________________
_______________________________________________________________________________
 Made up of only one type of _____________
 Each is represented by a symbol of 1-2 letters
 Elements in __________________ on the periodic table have similar _____________________ and
_____________________ properties
Compound
 Compound: a pure substance formed when two or more different _____________________ combine
 Each has a ____________________________ (H2O) and formed by a specific
__________________________ of elements in a fixed _______________
 They are ________________________ and physically different than the elements that make them up
 H = gas, O = gas, together they make H20 = liquid
Chemical Bonds
 ________________________________________________________________________________
 ____________________ is stored in the bonds when they are made, and when bonds are
______________________, they release ____________________
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Covalent Bond: ________________________________________________________________
A compound that has _____________________ bonds is called a ______________________
Most compounds in living organisms have covalent bonds
Ionic bond: _______________________________________________________________________
_________________________________________________________________________________
Substances formed by ionic bonds are called ionic compounds
 Ions: sodium, potassium, calcium, chloride and carbonate ions
 Help to maintain ____________________________ and transmit signals among cells to see,
taste, hear, feel and smell
Van der Waals Forces
 Van der Waals Forces: ______________________________________________________________
_________________________________________________________________________________
 ____________________ are in _______________________ motion around a nucleus, causing an
uneven __________________________ of the electron cloud
 This creates areas of slightly _____________________ and _____________________ charges
 Not as ________________ as covalent or ionic bonds, but determined by the size of the
______________________, its shape, and its ability to attract ______________________
 Important in _______________ molecules and biological processes
6.2 Chemical Reactions
Chemical Reactions
 when two or more ________________________________________ mix together and create a
______________ substance that is different than the _______________________ substances
 Chemical bonds are broken and the atoms in these substances are ________________________!
 Clues that a chemical change is happening include:
• Production of heat or light
• Formation of a new gas, solid, or liquid
 The key to starting a chemical reaction is _________________, usually in the form of __________
 Activation Energy: ________________________________________________________________
Exothermic Reactions
 Exothermic: ________________________________________
__________________________________________________
 More ______________ in the bonds of the reactants compared
to the bonds of the ____________________
 Freezing, Condensation
Endothermic Reactions
 Endothermic: _______________________________________
__________________________________________________
 More _____________ in the bonds of the product compared to
the bonds of the ____________________
 Melting, Boiling, Evaporating
Enzymes
 All living things are “chemical factories” driven by
________________________________
 Sometimes the input and amount of energy needed for a
reaction to occur is so _____________, that the reactions would
occur incredibly slow if allowed to occur on their own
 In order to reduce the activation energy,
_________________________ substances are required,
allowing the reaction to happen more quickly.
 Catalysts: ___________________________________________
___________________________________________________
• It doesn’t change what is made, or how much is
made…only how fast it is made
 Enzymes: __________________________________________
__________________________________________________
• Enzymes are essential to life and most are specific to one
________________________
 An enzyme’s name describes what it does:
 Amylase breaks down amylose
 Maltase breaks down maltose
 Lactase breaks down lactose (lactose intolerance is when
lactose isn’t broken down by lactase, causing bloating, gas,
diarrhea)
 Substrate: ___________________________________________
 Active Site: Where the _____________________ and
____________________ bind together
 The enzyme/active site fit together like
__________________________________. Once together, the
active site changes shape.
6.3 Water and Solutions
Water
 The properties of water make it well suited to maintain homeostasis in an organism
1. __________________________________________
2. __________________________________________
3. __________________________________________
4. __________________________________________
 One side of the molecule has a slightly ______ charge and the other has a slightly _____ charge,
making it ____________________
 Water molecules bond to each other with _____________________________, the hydrogen is
attracted to the oxygen.
 A hydrogen bond is a strong type of _________________________________
 Water is a _________________________________________________
 Solvent: ______________________________________________________________________
 Solute: _________________________________________________________
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Homogeneous Mixture: ________________________________________________
 Powdered drinks, Solutions
Heterogeneous Mixture: _____________________________________________
 salad
 Suspension: particles settle to the bottom
Water is _____________________________
Cohesion: ___________________________________________________________________
It has a strong attraction to other water
molecules, giving it high
____________________________.
This causes droplets to form.
Water is __________________________
Adhesion: ______________________________
_______________________________________
It forms ______________________ bonds with
other molecules on other surfaces (think of tape)
This causes ______________________________________ (water travelling up the stems of a plant)
Acids and Bases
 Remember, water is a universal solvent because of its ______________________
 Your body is about 70% water
 When molecules break down, or dissociate, in water, some release _______________________ ions,
other release __________________________ ions
Acids
 Acid: ____________________________________________
_________________________________________________
 The more hydrogen released, the more ________________
the solution becomes
Bases
 Base: ____________________________________________
_________________________________________________
 The more __________________________ released, the more basic the solution becomes
pH Scale
 The measure of how acidic or basic a solution is based on the ___________________________ of
hydrogen and hydroxide ions
 _________ = Higher acidity, __________ pH
 _________ = More basic, ___________ pH
 Acids and bases are key substances in biology.
 All the chemical reactions in the body happen in certain ideal _________________________,
environments, and pH’s, usually between the pH of ______________________ – HOMEOSTASIS!
Buffers
 Buffers: _________________________________________________________________________
 Antacids
 Your blood
6.4 The Building Blocks of Life
Carbon
 ____________________ is an
element in most biological
molecules.
 It has ________ electrons in its
outermost shell so it likes to make ______________________ bonds with other elements
 Anything with carbon is “______________________”
 Organic = CARBON BASED
 Organic Chemistry: ________________________________________________________________
Macromolecules
 Macromolecules: ____________________________________
___________________________________________________
___________________________________________________
 Polymers:___________________________________________
___________________________________________________
___________________________________________________
Biological Macromolecules
 _______________________, Lipids, _________________, Nucleic Acids are all biological
macromolecules
 The ________________________________ uses lipids, carbohydrates and proteins to help
maintain _________________________ in organisms!
 Nucleic acids are part of your __________!
Carbohydrates
 Sugars, ___________________, cellulose
 “carbo-” = ______________________
 “hydrate” = water (H2O)
 For every ___________________ there is a ____________________.
(C H2O)n
n = the number of CH2O units in a chain
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Key role as a source of _____________________
Some are a source of _______________________ (like cellulose for a cell wall in plants), or Chitin
which makes up the ______________________________ of things like shrimp.
Lipids
 Molecules made mostly of
______________________ and
________________________
 Fats, oils, and waxes
 Composed of fatty acids, glycerol, and other
components, mainly used to store _________________
 Important for ___________________________________________ (lets things go in/out of the cell)
 Steroids: estrogen, ____________________________ and cholesterol (also, the bad ones)
 Saturated Fats
 Found mostly in animal fats, associated with higher __________________________, obesity,
heart disease (atherosclerosis- hardening of the arteries) etc…
 Unsaturated Fats
 Better in small amounts, _____________________________, better skin, supposedly help with
depression, keep ____________________________ down.
 Some research suggest they keep your brain healthy!
Proteins
 Compound made of small carbon compounds called ________________________________.
 Amino Acids: small compounds made of _______________________________________________
__________________________________________________________.
 Make up about 15% of your body mass and structures like muscles, skin and hair.
 They also give other structure, they
are used to transport things, they
are used to
____________________________
signals with in the cell and between
cells, they speed up chemical
reactions and control cell growth.
Nucleic Acids
 Store and transmit
____________________________
_____________.
 Made of repeating units of
__________________________,
nitrogen, oxygen,
_________________, and hydrogen
 ___________ (ribonucleic acid) and
___________ (deoxyribonucleic
acid)