Some students have asked for further examples of what we are covering, so I
have provided these examples. They are meant as a supplement to the
lecture and the reading, not as a substitute for them. No questions will
be pulled directly from these examples, but they are examples of material that
we have covered.
Lesson 1: The
7 Characteristics of Life:
Living Things are Composed of Cells:
Single-cell organisms have everything they need to be self-sufficient.
In multicellular organisms, specialization increases until some cells do
only certain things.
Things are Organized at Different
Living things must be able to organize simple substances into complex ones.
molecular, and cellular organization are found in a living thing.
Living things organize cells at several levels:
Cell -the smallest unit of life (subcellular organization has been
- a group of cells that perform a common function.
- a group of tissues that perform a common function.
- a group of organs that perform a common function.
- a complete living thing or entity.
- Organisms also organize at several
- Populations -The unit that changes with time.
- Communities -all populations in an area
- Biome -wherever life can be found on the planet Earth.
2. Living Things have Heredity
- DNA is the molecule of heredity
Things Have Metabolism:
- Living things take in energy (ie light or food) for
maintenance and growth.
- Living things do this using metabolism, the chemical reactions of
- Metabolism allows living things to respond to their environment:
Things have Homeostasis:
- Living things make changes to keep their internal environment within
a certain narrow range.
- Shivering is an example of homeostasis to keep the body warm.
Living Things Grow:
Cell division - the orderly formation of new cells.
Cell enlargement - cells grow to a certain
size and then divide.
An organism gets larger as the number of its cells increases.
the filming of the show "Growing Pains,"
the kids did grow. :>)
Things Reproduce Using DNA:
Reproduction is essential for the survival of a species.
the example at the right, the parents reproduce and the child grows.
All living things reproduce in one of the following ways:
Asexual repoduction - Producing
offspring without the use of gametes.
Sexual reproduction - Producing
offspring by the joining of sex cells.
Things Adapt and Evolve in Response To Their Environment:
Adaptations are traits giving an organism an advantage in a certain
Variation of individuals is important for a healthy species, without it, the
species cannot adapt.
Lesson 2: The Scientific Method
Scientists think about the world in two ways:
- Deductive reasoning -Makes a
decision by applying a general principle.
- Inductive reasoning -Makes a
general principle by applying many different specific observations.
- Example, we think HIV
causes Aids because of many observations showing a correlation of the two.
A direct test has never been done.
If someone were to
inject Feline Immunodeficiency Virus into laboratory cats to show that it
causes kitty Aids, that would be Deductive reasoning.
These two ways of thinking about Science lead to Two
Approaches to Science
In Discovery science, scientists only use observations to learn about the
world. HIV example above.
In Hypothesis-based Science, scientists use experiments to test something
about the world. Observations are used in the experiment.
An example would be testing the cats with FIV above.
Video on the
(is a google video but most players can play it. If it does not work, find the
file "NASA_iFile_TheScientificMethod.gvi" found in this folder,
right click on it and open it with your video player (VLC, Windows Media Player
work). Or pull it directly from the internet from this link:
hypotheses -an educated guess about an observation.
INDEPENDENT VARIABLE – the one thing in the experiment
that is changed between the two groups in your experiment.
CONSTANT Variables – the things that are the kept the
same between the groups.
DEPENDENT VARIABLE – the thing (or things) in the
experiment that you are measuring. It depends on the independent variable.
Lesson 3: Chemistry
- The world is made up of atoms of pure substances we call elements.
- Atoms are the smallest thing an element can be and still have the property of
- Compounds are made up of atoms to two or more elements, such as water.
- Atoms of the same element can only have one specific number of protons,
depending on the element.
- However, atoms of the same element can vary in their number of neutrons.
3 Kinds of Chemical Bonds:
- An Atoms can Interact with other Atoms forming a Chemical Bond.
- Ionic Bonds
- Covalent Bonds
- Hydrogen Bonds (H-Bonds)
- Hydrogen bond between water molecules:
Lesson 4: Biomolecules
1. Living things are based on Carbon
- all biomolecules (the molecules of life) are built on carbon atoms
- carbon can bind to four different atoms, making a near infinite number of
- these molecules based on carbon are called organic molecules and include
all biomolecules of life
2. There are 4 biomolecules of life (4 families)
- nucleic acid
- these molecules are only found in living things or something that was once
3. Cells build their biomolecules from the four building groups (one
for each family of biomolecules)
- simple sugars
- fatty acids
- amino acids
- these building blocks are called monomers, mono means 1, or 1 simple
- the monomers can be combined to make larger molecule called polymers,
meaning many monomers
4. Carbohydrates are the first family of biomolecules
- simple sugars
- cells use them as Energy sources, for building blocks to make other
& as structural materials in cells and in organisms
- these molecules contain carbon, hydrogen, and oxygen and are polar
(dissolve in water)
|Carbohydrates that we cannot digest
(such as cellulose) are fiber in our diet.
|5. Lipids are the second family of biomolecules
(the order or number of
the family is not important)
- they are mostly hydrogen and carbon, making them mostly non-polar
- they are greasy or oily or waxy molecules and little tendency to dissolve
- They function in energy storage, membrane structure, and coatings
- fats and phospholipids are made up of glycerol and fatty acids
(other lipids are not)
- triglycerides are the most common fat in your body, have 3 fatty acids
combined to glycerol
- phospholipids are in membranes, have 2 fatty acids and a phosphate group
connected to glycerol
- phospholipids are unusual lipids because one end is polar
and one end is nonpolar (fatty acid tail)
- proteins are the most diverse of all the biolmolecular families
- they have numerous functions including acting as enzymes, in cell
movement, as storage and transport agents, as hormones, as antibodies, and
as structural material in cells and organisms.
- They are composed of carbon, hydrogen, oxygen, and nitrogen
- they are polymers made up of 20 different amino acid monomers
Proteins have 4 levels of structure (abpve right)
- Amino acids have:
- an amino group (NH2 or NH3),
- a carboxyl group (COO- or COOH),
- and one of 20 varying R groups that varies with the amino acid.
- Primary structure -the ordered sequence of amino acids in the
polypeptide, all are linked together by peptide bonds.
- Secondary structure -refers to the helical coil (as in hemoglobin) or
the sheet-like array (as in silk) of the polypeptide. This secondary
structure is result of hydrogen bonding between side groups on the amino
acids in the polypeptide.
- Tertiary structure -the result of folding of the molecule due to
interactions among R groups along the polypeptide chain.
- Quaternary structure -the getting together of multiple polypeptides
(if the protein is made of more than 1 polypeptide)
- video of
4 levels of Protein Structure
7. The last family of biomolecules are the Nucleic Acids
- these are polymers of nucleotides
- nucleotides and nucleic acids are polar (and ionic) molecules
made up of
carbon, hydrogen, oxygen, and nitrogen
- They act as chemical messengers of cells, energy carriers (ATP),
transport hydrogen atoms and electrons (examples: NAD+ and FAD),
blocks for nucleic acids.
- Nucleic acids serve as the hereditary instructions of all cells (DNA)
in translating DNA to build proteins (RNA)