Download Chapter Six – Chemistry in Biology – Study Guide for End of Chapter

Chapter Six – Chemistry in Biology – Study Guide for End of Chapter
Section 6.1 – Atoms, Elements, Compounds
 Atomic structure – atoms, protons, electrons, neutrons, energy levels for electrons
2, 8, 18
 Elements, compounds
 Chemical bonds – involve electrons of atoms and outer level either being filled or
brought to 8 electrons
o Covalent bonds – share electrons – form molecules such as water, glucose
(C6H12O6), oxygen (O2)
o Ionic bonds – transfer electrons
 Give up electrons to another atom – leaves a positively charged ion
 Receive electrons from another atom – creates a negatively
charged ion
 Sodium chloride – Na+Cl- is an example of an ionic compound
Section 6.2 – Chemical Reactions
 Reactants either form or break bonds to result in products
 Energy is either released or used
 Activation energy – amount needed to get a reaction going
 Catalyst / enzyme – special chemicals which by their presence lower the
activation energy and speed up reactions without taking part in the reactions – act
like a lock / key mechanism
 ALWAYS the same number of atoms in the reactants as in the products
Section 6.3 – Water and Solutions
 Water is polar – has a positive and negative side which gives it unique properties
 Water contains H2O molecules, hydrogen ions, and hydroxyl ions
 Solutions of water can be acid, base, neutral and are measured on the pH scale
from 0 – 14. (7 is neutral, less than 7 is acid, greater than 7 is basic or alkaline)
 Buffers are chemicals in cells that help keep the pH close to neutral
Section 6.4 – The Building Blocks of Life
 All life forms are made of similar large molecules with a carbon skeleton
(organic)
 These large molecules (polymers) are built from basic building blocks
(monomers) that are connected in chains or rings so of which can be thousands of
pieces long
 Carbohydrates – C,H,O – 2:1 hydrogens to oxygen, monomer is glucose, kinds
include sugars, starches, glycogen, cellulose – used for energy source and
structures
 Lipids – also of C,H,O – hydrogens to oxygen more than 2 to 1. Monomers are
glycerol and 3 fatty acids. Types include fats, oils, waxes – used for energy
storage, structural, protection
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Proteins – C,H,O,N – monomers are called amino acids (20 kinds) joined together
in chains of 300 to 30,000 forming large twisting and turning molecules that
provide structures for cells and also are enzymes to drive cell chemical reactions
Nucleic Acids – C,H,O,N,P – monomers are called nucleotides (5 kinds) hooked
together in very long chains. Deoxyribonucleic and ribonucleic acids are the
blueprints for life (DNA and RNA)