Name _____________________________________________________________
Test Date _Fri, 9/3______
UNIT 1 - INTRODUCTION TO BIOLOGY
I. INTRODUCTION TO BIOLOGY
(pp.16-22)
A. Complexity of Life
Biology is the study of _life___. To study “life” is to study a subject that is awesomely complex. Our common goal is
that you _understand____ life because it is only when you understand that you can truly _learn_____ . . . And
as the wise Mrs. Rice says, “If you _memorize_____, you _forget____; when you _learn______, you
_remember_____! ☺ To accomplish this, there are two important keys:
1. Active Listening – Listening is not a passive activity! An active listener ________________________________
__________________________________________________________________________________________
2. Responsible Learning - _____________________________________________________________________
__________________________________________________________________________________________
B. Characteristics of Life
1. Living things are made of _cells___ . A cell is the _smallest working unit of life____________
2. Living things obtain and use _energy_____. Our ultimate source of energy is the _sun_____. Plants
can convert the sun’s energy into useable energy in a process called _photosynthesis____. The chemical
processes that occur in an organism to convert food to _energy__ are known as _metabolism____.
3. Living things _respond to their environment_______________. Living things react to a
_stimulus____; for example, _temperature, light__________.
4. Living things maintain a _constant__ internal environment. This is known as _homeostasis__
or _internal harmony____.
5. Living things _grow and develop_______. Development describes _physical changes __
that take place during the _lifetime___ of an organism.
6. Living things are based on a _universal genetic code______ - _DNA___.
7. Living things _reproduce__. If this did not occur, _species would die out____
8. As a group, living things _evolve____; this means, _change over time______.
C. Hierarchy of Life
1. _Atom____ - Smallest unit of matter that retains its elemental properties
2. _Molecule___ - Groups of atoms bonded together
3. _Cell__ - Smallest working unit of life
4. _Organism___ - Individual living thing; depending on the complexity, an organism may be composed of:
a. _Tissue_______ - groups of cells working together
b. _Organ____ – groups of _tissues___________ working together
c. _Organ system___ - groups of _organs___ working together
5. __Population_____ - Group of organisms of one _species__ in one area
6. _Community____ - Different populations that live together in a specific area
7. _Ecosystem_____ - A community and its _non-living components___________
8. _Biosphere______ - Earth
II. THE CHEMISTRY OF LIFE (pp. 37, 38)
Organisms are composed of _matter___, which is anything that takes up space and has mass. All matter is
composed of _elements_____, substances that cannot be broken down by chemical reactions.
A. Elements – There are 92 naturally occurring elements, 25 of which are essential to life. Four elements make up
96% of living matter. They are:
 _carbon___________
 _hydrogen___________
 _oxygen___________
 _nitrogen___________
B. Compounds - Elements combine together in fixed ratios of atoms to form _compounds_______. Compounds are
held together by _chemical bonds_________. The reactivity of an atom and the type of chemical bond that it
forms are determined by the number of _electrons____ it has.
1. Chemical Formula - _Chemical description______ of a compound. Identifies the _number___ of _atoms____
of elements that make up the compound. Identifies the _ratio__ of _atoms__ of elements that make up the
compound.
H2SO4 = _2 hydrogen atoms, 1 sulfur atom, 4 oxygen atoms______________________________
 Total number of atoms = _7__
C6H12O6 = _6 carbon atoms, 12 hydrogen atoms, 6 oxygen atoms_____________________
 Total number of atoms = _24____________
2. Chemical Equation – Provides the “_recipe__” for making a compound. The substances that go into the reaction
are known as the _reactants_____. The substance(s) formed is known as the _products___.
2H2 + O2 2H2O
 Reactant = __H2 and O2_____
 Product = _ H2O________
C. Chemical Bonds (pp. 37-38)
1. Ionic Bond – Weaker bond in which electrons are _transferred______- that is, one atom _strips____ an
electron(s) away from the other. Results in 2 oppositely-charged particles called _ions____ that are
attracted to each other due to the difference in _charges___. Examples include _Na+Cl-_______________
2. Covalent Bond– Strong chemical bond in which electrons are _shared________. Results in a very
stable compound called a _molecule____. Examples include _water, glucose, DNA_____________.
III. THE IMPORTANCE OF CARBON (pp. 44-45)
Although a cell is composed of 70% to 95% _water____, most of the rest consists of carbon-based compounds.
Carbon can form very large, complex molecules called _organic____ compounds due to its number of electrons.
Organic molecules important in organisms are called _biomolecules_____.
A. Polymers - Most biomolecules are _polymers____. The prefix “poly” means _”many”______. A
polymer is a large molecule composed of _many__ identical or similar building blocks. The sub-units,
or building block molecules, of a polymer are called _monomers___.
B. Classes of Biomolecules:
1. _Carbohydrates________________
2. _Lipids_______________________
3. _Proteins_____________________
4. _Nucleic Acids_________________
IV. CARBOHYDRATES
(p. 45-46)
Carbohydrates are used for immediate and stored _energy____ and as a _building material____________.
Carbohydrates contain the elements _C_, _H__, and _O___. The ratio of _H___ atoms to _O___ is
_2 : 1____. In other words, for every _2 hydrogens__ in a carbohydrate, there is _1 oxygen____. There are
three groups of carbohydrates:
A. Monosaccharides – “_One__ Sugar”. Simplest of all sugars. Although they vary in the number of _C___ atoms,
the ratio of _2 H : 1 O_____ is always present. Monosaccharides are the building blocks, or _monomers_____, for
the more complex carbohydrates. Examples of monosaccharides include
1. _Glucose____ – Six-carbon monosaccharide that is the preferred _energy source ___ for most organisms,
including _humans______. The chemical formula of glucose is _C6 H12 O6________.
2. _Deoxyribose_____ - Five-carbon monosaccharide; important component of _DNA_____.
B. Disaccharides - _Two__ monosaccharides _covalently____ bonded together. Examples include
1. Sucrose - _table sugar____________.
2. Lactose - _milk sugar_____________.
C. Polysaccharides - _Many __ monosaccharides _covalently___bonded together. They are divided into two groups
based on function - _energy storage____ polysaccharides and _structural_____ polysaccharides.
1. Storage Polysaccharides – Long _polymers___ of _glucose__ broken down as needed for _energy____
a. Glycogen – Storage form of _glucose___ in _animals___. In humans, most glycogen is stored in
_liver___ and _muscle___ cells.
b. Starch – Storage form of _glucose____ in _plants___. Humans are able to break down starch to its
monomers of _glucose_____ for energy.
2. Structural Polysaccharides – Used as a _building material____ in many organisms
a. Cellulose – Major component of _plant cell walls______. Composed of monomers of
_glucose___. Humans are unable to break the bonds in cellulose; therefore it cannot be used
for _energy___ but it is still important to our diet as a source of _fiber____.
b. Chitin – Major component of _fungal__ cell walls and the _exoskeletons___ of insects
and other arthropods.
V. LIPIDS
(p. 46-47)
Known for their _insolubility____ in water. Made up of _C__, _H___, and _O___, but lipids do not have the
_2H : 1O____ ratio found in carbohydrates. Our bodies need lipids for _energy storage, insulation and cushioning__.
There are 3 important groups:
A. Fats & Oils – Characterized by presence of _three fatty acid tails____. Generally referred to as
_fat___ if lipid is solid at room temperature and an _oil___ if lipid is liquid at room temperature. Fats and oils are
classified as _saturated ___ or _unsaturated_, depending on the type of covalent bonds in the
fatty acids. _Saturated ___ fats have been linked to heart disease.
B. Phospholipids – Unique lipid found in every living _cell membrane______.
C. Steroids – An important example of a steroid is _cholesterol____. Used for _hormone____ production and animal
cell structure.
VI. PROTEINS
(pp. 47-53)
Proteins are instrumental in _support, structure, movement, and metabolism________________________.
In addition to _C___, _H____, and _O___, proteins contain _N___.
A. Amino Acids - The monomers of proteins are _amino acids______. There are _20___ amino acids that
combine together in different _numbers_, _patterns__, and _arrangements___ to form proteins.
B. Enzymes - One very important function of proteins is to act as _enzymes__. Enzymes are biological
_catalysts_____, meaning they _trigger_____ chemical reactions. An organism could not
maintain _homeostasis____ without functioning enzymes.
VII. NUCLEIC ACIDS
(p. 47)
Nucleic acids are _polymers_____ composed of monomers called _nucleotides____.
There are three important molecules in this group:
A. DNA - Contains the _genetic instructions_____ for the cell.
B. RNA - _Carries out __ the instructions in DNA.
C. ATP – Provides useable _energy__ in all cells