After a full year in this class, you should know, at a minimum:
1. Most science experiments use a control (normal condition) group and an experimental
group (with a single variable changed or manipulated).
2. A hypothesis is the “predictive statement” being tested in an experiment. It usually takes the
form of: “The more (Independent variable) used, the more (Dependent variable) occurs.”
Ex. The more ultraviolet light exposure on a skin cell, the greater the frequency of skin
cancer.
-The Independent variable is the amount of violet light exposure-this is what I, the
scientist, change during the experiment.
-The Dependent variable is the frequency of skin cancer-the data collected as a result.
3. Data collected should be in easily measured units; organized in a table or graph.
In a 2 column table,
1st column is the Ind. var. or “x” axis; 2nd column is the Dep. var. or “y” axis.
In a 3 column table,
1st is “label” for the group, 2nd the Ind. var, 3rd the Dep. var..
On a graph, the Ind. var. is on the “x” axis; Dep. var. is on the “y” axis.
UV light exposure (lumens)
100
500
1000
2000
Skin cancer (# of cells)
8
120
250
450
OR
Group
A
B
C
D
UV light exposure (lumens)
100
500
1000
2000
Skin cancer (# of cells)
8
120
250
450
On the graph shown:
-the Ind. var. is “Auto. Speed.”
-the Dep. var. is “Cost of the average
speeding ticket.”
Hypothesis probably stated:
“The greater the auto’s speed, the greater
the cost of the speeding ticket.”
(Note: Data points may be connected “dot to dot” OR
with an “average trend” line.)
4. To improve any experiment: a) increase the sample size; b) repeat the test; or
c) “control for other factors” that might also have influenced the results.
5. If in doubt, the “other factors to control for” include: size of containers, amount of water used,
temperature of room, age/health of the test subjects as long as these were NOT the independent
variable(s) in the hypothesis.
6. Metabolism is the “sum of all life functions.” Common life functions include:
Growth – increase in cell size or number of cells
Respiration – “the release of energy from food”
C6H12O6 + O2  CO2 + H2O and lots of ATP (energy carriers)
Regulation – keeping conditions relatively similar; homeostasis; react/respond
Reproduction – make offspring to continue life of your species
Asexual – one parent, identical offspring
Sexual – two parents, non-identical offspring; meiosis to make gametes
followed by fertilization to make zygote which becomes embryo  baby
Excretion – removal of metabolic wastes
Nutrition – obtaining and converting food into smaller, easily moved forms
- autotrophic nutrition means “makes own food” or photosynthesis
- heterotrophic nutrition means “eats” and digests other organisms
Transport – move items around body (ex. circulation of food/wastes/oxygen in
blood OR pushing food down intestines by peristalsis)
7. There are several biochemical equations to MEMORIZE:
Aerobic respiration (in mitochondria)
Sugar + Oxygen  Carbon dioxide + Water and lots of ATPs
Anaerobic respiration (aka fermentation) (in cytoplasm)
Sugar  alcohol + Carbon dioxide
OR Lactic acid
Photosynthesis (in chloroplasts) (Note: Photosynthesis is “the opposite” of aerobic respiration.)
Carbon dioxide + Water and Sunlight  Sugar + Oxygen
Digestion of big molecules into “building blocks”
Starch  many simple sugar molecules
Proteins  many amino acids
8. Parts of cells are called “organelles.”
ALL cells have a semi-permeable cell membrane and cytoplasm (cell goo).
Ribosomes make proteins under direction from the mRNA.
Mitochondria are the site of aerobic respiration, releasing energy from food.
Vacuoles are storage sacs.
Cell walls are rigid structures around plant cells that give them shape.
Chloroplasts are the site of photosynthesis.
Nucleus contains DNA (genetic info) that codes for making proteins.
Recognize plant cells usually have chloroplasts, cell wall, larger vacuoles.
9. A cell is the “unit of structure and function” for living organisms.
Cells come from other cells. Cells may be organized as:
Organelle Cell  tissue  organ  organ system  large organism
10. Genetic information is found in the sequences of bases of a DNA. A single gene codes for a
single protein. Genes are found on chromosomes which are in the nucleus of a cell.
11. The “double helix” is DNA.
The “big X shape” is a “replicated chromosome.”
12. DNA is read by mRNA in the nucleus.
mRNA moves out to the cytoplasm.
mRNA tells tRNA at the ribosome which amino acids
to join together.
13. During mitosis for “normal growth and repair of
cells” DNA is exactly copied and each new cell has
identical DNA. Mitosis = “binary fission” or
“asexual reproduction of a single cell.”
14. Meiosis is “the making of gametes.”
Male gametes are sperm. Female gametes are eggs.
Gametes have ½ the DNA of a normal body cell and
gametes are not identical.
15. Fertilization is the “union of gametes” which make a
zygote. The zygote then uses simply mitosis to become an embryo, then fetus, then baby.
16. Sexual reproduction involves both meiosis and fertilization and guarantees that the offspring
show a variety of traits—a mix of traits from each parent.
17. Ecology of the “study of living things and their interactions with each other and their
environment.” This involves biotic factors (“living organisms”) and abiotic factors
(“non-living factors” such as gases, water, heat, light, space, and minerals).
18. Organization of living things studied in ecology follows the pattern of:
Individual organism  all individuals of one species in one area (population)
All populations of different species in one area  community
Community AND all abiotic factors in one area  ecosystem
Similar ecosystems in a large area  biome
All biomes on earth  biosphere
Summarized: Individual  Population  Community  Ecosystem  Biome  Biosphere
19. The flow of energy in an ecosystem generally follows the pattern of:
Sun (light)  Producers (photosynthesis)  Herbivores (plant eater)  Carnivores (meat eater)
20. Only 10% of the energy from any organism moves up to the next trophic (feeding) level.
A food chain and a biomass pyramid basically show the same things.
21. A food web shows a number of interconnected food chains. One may find omnivores in a food
web (eating both plant and animal material). Rarely, one may find decomposers in a food web
(eating almost everything and recycling the material in organisms).
In a food chain or food web, the “” is read as “is eaten by.”
22. Decomposers are bacteria and fungi; they recycle nutrients.
23. Relate a pyramid to a chain.
Kelp (producer)  Sea Urchin (herbivore/first consumer) 
Sheephead (carnivore/second consumer)  Giant Sea Bass (carnivore
and “top consumer)
With 2000 kilograms of kelp, one may have 200 kg of sea urchin,
20 kg of sheephead, and only 2 kg of giant sea bass.
24. Nutrients may recycle through an ecosystem.
Water cycle: Evaporation, Condensation, Precipitation,
Run-off, and long term Storage in oceans. (Repeat)
Nitrogen cycle: Bacteria use nitrogen in air to make
nitrates for plant use; plants make proteins; animals and
bacteria convert proteins into ammonia, urea, and other
proteins. Bacteria recycle most of the rest of the nitrogen.
Carbon cycle: carbon dioxide is used by plants to make sugar (glucose) by photosynthesis.
Plants and animals use sugar as an energy source (by aerobic respiration) to make carbon dioxide.
Any nutrient needed only in “small amounts” is called a “trace nutrient” and shortages of a
particular nutrient (trace nutrient or major nutrient) makes that nutrient a “limiting factor.”
25. Ecologic succession is “the replacement of one community by
another at a single place over a period of time.” The first organisms
in the area are pioneers, commonly mosses or lichen. The plant life
tends to get larger as succession continues. Grasses, shrubs, and trees
tend to follow in that order. The final, stable community that remains
for a long time is the climax community.
Primary succession occurs when no life existed in the area at the
beginning (volcanic island).
Secondary succession occurs when a stable community has been
disturbed by minor fire or other problem.
Commonly used examples for succession are shown.
26. Some ecology terms to memorize:
Niche – organism’s role or job in an ecosystem; if two organisms have the same niche, they will
compete with each other.
Habitat – place where an organism lives; if two organisms have the same habitat but do not have
the same niche, they will live nicely with each other
Predator – an organism that hunts and kills another organism (prey) for food
Parasite – an organism that hurts another organism (host) by using it (often for food) but generally
does not want to kill the host. Ex. tapeworms (parasite) in human (host) intestines
Symbiosis – a special relationship between two different species; if helpful to both (mutualism);
helpful to one but other does not care (commensual); helps one but hurts the other (parasitism).
27. A simple comparison of “good vs bad” actions for ecology.
Good actions
Bad actions
Bad because it….
a) Use native organisms
Import non-native organisms -may become invasive
-disrupts the food web
b) Preserve species
Kill organisms
-will reduce biodiversity
-may disrupt food web
c) Use natural predators for
Spray pesticides and -may bio-accumulate and hurt
insect control
other chemicals
other species up food chain
d) Use renewable energy
Burn dirty fossil fuel -CO2 may cause global warming
(solar, wind, hydro)
(coal, petroleum, gas) -SO2 causes acid rain
-future generations won’t have this
finite resource to use
e) Human population control Overpopulation
-humans act as invasive species
-humans over-use scarce resources
f) Preserve bio-diversity
Reduce bio-diversity -low bio-diversity = low stability of
ecosystem; poor response to change
28. Biomes change as the climate (long term weather) changes, such as: moving farther from equator
or moving up a mountain.
Land biomes include:
Desert – dry with large changes in day/night temperature
Tropical rain forest – warm and wet, high biodiversity with low population numbers
Temperate deciduous forest – four seasons with trees that drop their leaves
Grasslands – have grasses with wet/dry seasons
Alpine areas are like tundras –cold with permafrost and low growing plants (if any)
Marine biomes include:
Deep sea abyss – constant conditions of cold, dark, and barren
Estuary – where salt and fresh water mix; highest biodiversity and productivity!
29. The most common elements in a living thing are: Carbon, Hydrogen, Oxygen, Nitrogen, and
some Phosphorus and Sulfur. (CHONPS)
-Carbohydrates CH2O
(glucose = C6H12O6)
“-ose” is suffix meaning sugar.
Glucose is used as: “quick energy” and for moving energy from cell to cell. Starch and glycogen
are huge molecules made from thousands of glucoses – used for “long term storage of sugars.”
Huge molecules do not move from cell to cell.
-Proteins
CHON
(a string of amino acids make keratin, insulin, lipase, lactase)
“-in” is suffix meaning “protein that is not an enzyme”
“-ase” is suffix meaning “protein that is an enzyme”
Proteins are used as: structures; chemical messengers (hormones); message receivers (receptors);
cellular name tags (antigens); or to “speed up a reaction rate” (act as an enzyme).
When proteins are working, shape matters! A specific shape is
needed for a specific function. If the shapes do not fit, the protein
does not work! Ex. Enzyme-substrate or antigen-antibody
Enzyme shape temporarily changes due to changes in pH;
permanently by high temperature. “Destroyed enzyme” =
“denatured.”
-Lipids (also called fats and oils) CHO (big molecules made from glycerol and fatty acids)
Lipids are used as: very long term energy storage or as water barriers (in cell membrane).
-Nucleic acids CHONPS
(double helix of DNA or the smaller single strand of RNA)
Nucleic acids carry the “coded messages to make proteins” and are the “genetic materials” used to
transfer information on traits from parent to offspring.
-Compounds that contain both Carbon and Hydrogen are “organic compounds.” Common organic
compounds include: carbohydrates, proteins, lipids, and nucleic acids.
ATP is a special organic compound that is used as the “immediate energy carrier inside of cells.”
-Compounds that do not contain both Carbon and Hydrogen are “inorganic compounds.” The most
common inorganic molecules include: water (H2O), carbon dioxide (CO2), and common salt (NaCl).
Water is the most common compound in any living organism!
-pH is a measurement of the acidity of a solution. A very low pH (1-3) is very acidic. Slightly low
pH (4-6) is slightly acidic. pH of 7 is “neutral.” Slightly high pH (8-10) is slightly basic. A very
high pH (11-14) is very basic. Any pH value that is very low or very high tends to harm living
things by changing the shapes of their enzymes and disrupting metabolic reactions.
30. Transport processes in cells:
Diffusion is movement of small molecules across a membrane from high concentration to low
concentration until both sides are equal. Diffusion has no energy need.
-Cells placed in hypertonic (lots of stuff) solutions shrink.
-Cells in hypotonic (almost pure water) solution will swell.
Active transport is movement of molecules across a membrane from low to high concentration and
maintains an unequal situation. Active transport requires energy use.
31. Homeostasis – maintain fairly constant internal conditions (dynamic equilibrium) by making
slight responses to changing stimuli. Body regulation is rapid and short duration for
nervous control; slower and longer duration for endocrine (hormonal) control. Both
systems use receptors.
32. Graphs for homeostasis or dynamic equilibrium are
similar. “Hormonal control” example is: blood
sugar control by insulin (glucose goes in to the
cell; out of the blood) and glucagon (glucose be
gone from the cells and into the blood).
33. Genetics – study of how traits are passed from parents to offspring
Gene – portion of chromosome coding for a single trait. There may be several versions of
genes. If only one copy needed to show trait, trait is dominant (G). If all copies must
be the same to show trait, trait is recessive (g). Some traits are controlled by
“blending of traits” (Red – pink – white flowers ) or by multiple genes (the many
different blood types (A, B, AB, O). Other traits are “expressed” (turned on/off) by
outside influences (freckles on skin with sun or fur color changes with temperature
for rabbits/foxes).
Sexual recombination of traits due to meiosis and fertilization is the main reason for variety.
Mutations (or accidental DNA changes) account for “new” traits. Mutagens (radiation,
cancer-causing chemicals, etc) trigger mutations. Body cell mutation may cause cancer; but sex cell
mutation may be passed on to offspring.
Modern genetic engineering has allowed transfer of individual genes from one organism
into the cell of very different organisms/species. (Human insulin may be made by genetically
modified bacteria.) Cloning allows the entire set of genes from one cell to be placed into another
cell – making it possible to have many “identical twins, triplets, etc.” Stem cell research has allowed
different tissues to be changed into clones of the original organism.
Traits may be predicted by analyzing ancestors (in a pedigree chart); directly calculating %
odds in offspring (Punnett Squares); direct reading of genes by karyotyping and/or gene sequencing.
Ethical issues are common with genetic issues. What is normal? How to deal with genetic
diseases? Should we manufacture “new organisms” or “play God”?
34. Evolution or “natural selection” is an explanation how populations (not individual organisms)
change over many generations. Darwin suggested: a) variations exist; b) overpopulation leads to
competition for scarce resources; c) only traits found in survivors are passed on (“fittest”
organisms tend to have more offspring than sickly or dying organisms); d) traits found within
populations change over time. Organisms are considered “best adapted” if they have traits that
allow them to have many offspring. (For biology classes, never say that “an individual organism adapts” or that
an organism “needs to” do anything; these phrases only work for psychology or sociology classes!!!) “Survival of the
fittest” only means the organism had a certain set of traits and now has many descendents. The
opposite of evolution is “extinction” for the species.
35.Conditions favoring evolution: a) large variation of traits; b) high rates of mutation and/or sexual
recombination of genes; c) a changing environment; d) shorter life cycles; e) initially wide dispersal
of population followed by isolation under different conditions.
36. Evidence for evolution: a) fossil layers in sedimentary rocks; b) comparison of similar structures
(homologous structures); c) comparative biochemistry, esp. similar genes or parts of genes using gel
electrophoresis; d) comparing embryo development. Modern example - development of drug
resistant bacteria.
37. There is NO direction to evolution. Most species develop by “being lucky” and surviving
catastrophes that killed off the competition. Examples include: 1) photosynthesis made excess
oxygen - - killed off many of the original life forms which did not use oxygen (anaerobes) but also
allowed for development of ozone layer that blocks UV rays (that otherwise kill or cause skin
cancers) and allowed for aerobic (oxygen using) organisms to evolve; 2) Ice Ages reduce sea levels
and the cold kills off more “cold-blooded” organisms allowing the “warm-blooded” organisms to
take over the now vacant areas; 3) meteor crashes near Mexico – triggers events that kill off
dinosaurs and allow mammals to take over; 4) virus outbreaks/major plagues may wipe out
populations for reasons completely separate from typical “survival of the fittest” issues.
38. Disease is a disturbance in the normal homeostastis/metabolism of an organism that harms the
organism. Some diseases are infectious: bacteria, fungi, viruses, and some protozoans may cause
disease and spread from one sick person to a healthy person (often by touching, aerosol from coughs,
direct body fluid contact, or through a “vector organism” such as mosquito, tick, or flea). Other
diseases and non-infectous: exposure to toxic chemicals/occupational considerations; genetic,
cancer, hormonal imbalances, psychological, or simple “wear and tear” issues (osteoarthritis). Noninfectious diseases are not passed from a sick person to a healthy one.
Know examples of each type of disease, its normal progression, how it is diagnosed, and its
treatment or cure.
Different bacterial infections may be cured by different antibiotics.
Viral infections may be prevented by vaccination (exposure to weakened virus to “alert” your
immune system); the viral disease then “runs its normal course” or a shortened period if an anti-viral
medicine is used.
Fungal infections take a long time to respond to anti-fungal medicines – TB, leprosy, athletes foot.
Protozoans cause many common parasitic diseases – malaria.
Cancer is “uncontrolled cell growth.” “In situ” is “in one place” and may be cut out. “Metastatic”
cancer is potentially “anywhere in the body” so needs chemotherapy and/or radiation treatment.
What is the role of public health departments in the prevention of disease?
Common healthy living strategies may include….
39. Classification (or taxonomy) often uses a dichotomous key to identify different organisms.
The basic organization is: Kingdom, phylum, class, order, family, genus, species.
Prokaryotes are bacteria – the simplest organisms; no nucleus.
Eukaryotes are every other type of life – with a nucleus.
The five kingdom system: Monera (bacteria); Protista (ameba, paramecium); Fungi, Plants, and
Animals.
In a phylogenetic tree, the most related organisms share a “recent common ancestor.”
40. Human body systems: Nervous, Circulatory, Endocrine, Excretory, Reproductive, Muscular,
Skeletal, Respiratory. Many organs are part of several body systems. Recall common seventh grade
themes: RBC- carry oxygen; WBC – fight infection (immunity); bones – support/locomotion/make
blood; digestive system – breaks down food into smaller, easily absorbed molecules in the small
intestines; liver – processes chemicals; lungs – gas diffusion; muscles - work by contraction often in
opposing pairs.