General Biology Concepts review for EOC
Themes:
Systems: Flow of Energy and Matter, Change over time (Evolution and ecology), homeostasis (cell
biology, body system responses)
Inquiry: Experimental design and making conclusions (data analysis)
Application: Solving real-world problems
Chemistry you need to know:
Carbohydrates (polymers) are made of sugars (monomers) , and they contain C, H, and O. Their
function is ENERGY (carbon fuel).
Lipids are fats, oils and waxes and are made of mostly long Carbon-Hydrogen chains, with some groups
(usually -OH) on their ends, so again C, H, and O.
Their functions are, insulation, waterproofing and in the phospho- lipid bilayer of cell membranes, energy
storage.
Proteins (polymers) are made of amino acids (monomers) and have C, H, O, and N for elements. Their
linking bonds are called peptide bonds. Their functions are structural, as in cytoskeleton, muscle,
spindle fibers, and they also act as enzymes to metabolize food and lower the activation energy of other
reactions in living cells.
Nucleic Acids, are DNA and RNA, and their function is to hold the genetic code (DNA has the building
instructions) and (RNA) to read and transfer the code to actual protein synthesis.
Remember the three differences of RNA, RNA has a single not a double helix like DNA, has Uracil (U)
instead of Thymine (T) as a base, and ribose instead of deoxy-ribose as the sugar in its sugar-phosphate
backbone.
Remember the code for DNA replication is A-T adenine pairs with Thymine , G-C: Guanine pairs with
Cystosine .
And from DNA to RNA (transcription) it’s A-U: Adenine - pairs with Uracil, G-C: Guanine pairs with
Cytosine
ATP is an energy molecule for cells. It can easily release energy when needed by breaking off the third
phosphate group and becoming ADP. The phosphate group then can be restored during cellular
respiration in the electron transport chain of the mitochondrial matrix.
pH: Don’t forget your acid/base facts:
The scale is logarithmic and goes from 1-14.
1-6.5 are acidic (red) pH’s,
7.5-14 are basic (blue) pH’s,
and the neutral zone is right around 7.0 (green)
Photosynthesis Reaction:
6CO2 + 6H2O + Sunlight Energy ---- C6H12O2 + 6O2
*Main purpose is to trap energy in a chemical form that can then move through the food web. Not only
does the energy move through the food web, the C, H, and O also transfers.
Cellular Respiration Reaction:
C6H12O6 + 6O2 --- 6CO2 + 6H2O + Energy
(in the form of ATP).
Main purpose is to release energy by breaking bonds of the sugar so it is trapped in smaller amounts that
are more useable for cellular demands.
Other chemistry and solution concepts that appear on biology tests:
1) Activation energy and enzymes as catalysts in metabolism: Enzymes lower activation energy.
 Factors that affect enzyme activity:
o Heat- speeds up reactions to a certain point due to increased kinetic energy and collisions
of enzymes and substrates. At higher temperature, denaturing occurs to the enzyme.
o pH (acid and bases)- Usually negatively affects reaction rate due to denaturing enzymes.
o Concentration- Increases due to more collisions (more crowded)
2) Concentration and concentration gradients:
Concentration gradients: Difference in concentrations. Causes diffusion and osmosis (molecules move
from higher to lower concentrations. This brings nutrients and waste into and out of cells and blood.
3) Osmosis:
Water concentration changes around a cell can cause it to swell (higher outside of cell) or shrivel
(lower outside of cell).
4) Permeable, semipermeable and selective membranes. The ability
for a cell to regulate what can enter or leave it helps it maintain
homeostasis (an internal environment needed to work properly).
Cellular Biology: know the function of the organelles and the definition of
prokaryotic and eukaryotic cells:
Prokaryotic, as in Bacteria and Archae-bacteria, no membrane bound
nucleus, few organelles, small and simple in organization. Evolved first.
Eukaryotic, as in all other kingdoms, have a nucleus and many other membrane bound organelles.
Mitochondria, site of cellular respiration, and therefore energy transfer in all cells.
Chloroplast: site of photosynthesis in autotrophic cells convert solar energy to chemical energy in
glucose molecules.
Ribosomes: make proteins. .
Cell membrane, the phospholipid bilayer, see below “transport” .
*Rarely do they ask about other organelles like the golgi bodies or endoplasmic reticulums, vacuoles, or
centrioles on tests.
Cell processes:
Transport, active (requires energy in form of ATP) and
passive (diffusion, osmosis) and everything to do with
the cell membrane often appear on tests.
Mitosis, specifically the phases of, prophase, metaphase,
anaphase, etc. is being phased out of testing.
Remember it is cell division for somatic (body) cells and
is diploid to diploid in nature. Passes genetic info to new
cells.
You may be asked questions about the cell life cycle. So remember the growth phases - when the cell is
translating into proteins , growing and maturing, and the and synthesis phase-when the cell is
replicating DNA, both occur in INTERPHASE.
Meiosis, again, hopefully no phases! But do know that sex cells or gametes become haploid (go from
diploid to haploid) through this cell division process.
Transcription and Translation: are difficult concepts and do appear on standardized tests in Biology.
Use your knowledge of the RNA/DNA differences, (watch for U or T in the coding strand) to figure out
what process is pictured in the test question. Review theDNA/RNA differences in the chemistry section
of this document.
Mutations: Relate what you have learned about how DNA is read to create proteins (read as codons in 3
base sections) to be able to understand why frameshift mutations (addition or deletion of a nucleotide)
causes changes to many amino acids and the stop codon (all codons shift and are changed after the
mutations. Point mutations usually only change 1 codon and 1 amino acid if it is in a gene.
Types of RNA:
mRNA take the code from nucleus to cytoplasm (transcription) .
tRNA finds the correct amino acid. Codons, and their partner anticodons, have a three-letter code for
each amino acid.
rRNA make up all ribosomes to build the protein chain on, and are made in the nucleolus of the nucleus.
Occasionally you get the question of which organelles contain nucleic acids? Ribosomes and the
nucleus are obvious, but there is such a thing as mitochondrial DNA and RNA and chloroplast DNA
and RNA too, leading to the theory of endosymbiosis, that these small organelles were ingested by
heterotrophic cells and “assimilated” instead of digested.
Organization in living things: Starts with a cell, then tissue, then organ, then system, then organism.
Mendelian Genetics Testing tips
I am not going to review all of genetics here, but
1) Remember each parent passes an allele to offspring for each gene (2 alleles per gene)
2) Do DRAW a Punnett Square to calculate ratios of monohybrid crosses, don’t guess.
3) Do Read questions carefully and double check the genotypes and phenotypes of the parents
and offspring.
4) Do Remember your simple examples of incomplete dominance (pink flowers, roan cows) and
co-dominance (red and white flowers, spotted cows) .
5) Do know that the phenotype ratio of a standard di-hybrid cross is 9:3:3:1.
Tips on Ecosystem Test Questions:
1) The arrows in food webs refer to flowing energy and always go from producer (autotrophs) to
first degree consumer (heterotrophs) , to second degree consumer, etc. not from biggest predator
on down. There is a 10% rule for going up trophic levels in the pyramid in terms of energy.
2) Biomagnification is the concept where the pollutant gets into a first degree consumer- usually
insects or mice on land or small krill in the ocean--and the biggest predators get that toxin built up
in their bodies over time as they feed. * DDT, a pesticide, is a famous example from the 19501970’s that nearly made The American Eagle extinct.
3) Organisms live in populations of their (one) species.
4) Populations form communities of both symbiotic and sympathetic species but also of
predator/prey species and plants and decomposers too. Communities contain several living
populations. These are all biotic factors! Every species must have a niche in their community,
for example: a species of bacteria’s ‘niche’ might be to decompose dead organic matter.
5) Add the abiotic factors of nutrients, temperature, moisture, rocks, rivers, grass, sand, air, climate,
weather, etc. to your communities and you have an ecosystem.
6) Ecosystems that share similar plant life, climate and rainfall patterns make up biomes. All living
things on the planet make up the biosphere.
Nutrient Cycles: They will ask you about flowing matter and the uses for some nutrients. The main
nutrients they will ask you about are Nitrogen and Carbon (and maybe phosphorus).
Nitrogen Cycle:
 The atmosphere is 78% N2.
All organisms need nitrogen to make DNA and proteins.
Most organisms cannot use the N2 in the atmosphere.
A certain type of bacteria can “fix” nitrogen- which means to
break apart an N2 molecule and convert it into nitrogen
compounds that can be used by plants and other living things.
These nitrogen fixing bacteria can live in the soil or on the
roots of certain plants (in a symbiotic relationship.)
Nitrogen is passed along the food chain and recycled by
decomposers.
 Nitrogen is need to make Protein and DNA/RNA.
Carbon Cycle: Photosynthesis and Cellular Respiration are key to cycling Carbon.
Photosynthesis: Uses the sun’s light energy to make glucose, which stores chemical energy. O2 is also
produced. Occurs in chloroplast.
Food Chain
CO2 + H2O
Glucose
In plants
Glucose in consumers
Cellular Respiration: Sugar is broken down to use the energy stored in the sugar to make ATP. Occurs in both
plants and animals (and other aerobic organisms) in the mitochondria.
(Anaerobic organisms also break down food molecules to make ATP but without O2 and produce less
ATP per sugar.)
Cellular Respiration: Sugar is broken down to use the energy stored in the sugar to make ATP. Occurs in both
plants and animals (and other aerobic organisms) in the mitochondria.
Most of the matter/mass in a plant comes from the carbon dioxide in the air and water which are used to
build the glucose.
Plants need other nutrients to be able to build DNA, protein, and ATP (esp. nitrogen and phosphorus). Without
these nutrients plants cannot grow (and gain mass).
(Anaerobic organisms also break down food molecules to make ATP but without O2 and produce less ATP per
sugar.)
Overall, plants perform more photosynthesis than cellular respiration (as shown in increase of mass) but still
consume some of the O2 they release for cellular respiration. (NET release of O2 but use some O2.)
 There is a recycling of matter in an ecosystem.

There is a one-way flow of energy through a food chain, forming an energy pyramid since not all of the
energy is transferred through the system.)
Evolution:
Charles Darwin’s 14 finches are an example of “adaptive radiation” .
His book was called “The Origin of Species”
The three accepted evidences for evolutionary theory are
DNA analysis- The strongest evidence. Change in species is due to change in genetic make-up. All
life uses the same genetic code and the more genetically similar, the more closely related.
Anatomy comparisons & The fossil record:
Homologous structures, have a divergent evolutionary path, a common ancestor, and different
functions. Ex: bat’s wing, whale flipper, human hand.
Analogous structures have a convergent evolutionary path, different ancestry, and similar
functions. Ex: Cats whiskers and ant antenna.
Vestigial structures are no longer needed by their organism. Ex: appendix, tails in chimps.
The oldest fossils occur in the deeper and older layers of a fossil bed. This seems obvious, but
I have seen this concept on biology tests!
Body Systems: There will not be any questions on specific body systems, but will be on how body
systems (or other systems) respond to changes, specifically feedback loops.
Feedback loops: Feedback is the process by which the output of a system causes further
influence on the system.
Positive feedback loops: The response would cause further change to the system that would
promote the direction the system is heading (either an increase or a decrease). Think of it reinforcing
the current trend.
Example: Increased births in a deer population result in a larger population size, which causes a
further increase in the birth rate.
Negative feedback loops: The response would cause change to the system that would be in the
opposite direction to the system’s current trend. Think of counteracting the current trend.
Example: Your body temperature goes up, your body responds by sweating that brings the body
temperature lower.
Tackling the Written Questions on scientific process and methods:
Experimental methods: Practice writing logical procedures by mentally breaking down your daily
doings into logical steps: “My alarm goes off, I hit snooze, it goes off again, I get up and brush my teeth”.
They often have a previous procedure they have written that you should use as a model!
Look for all the parts of good science in the presented scenarios:
Do they have an experimental control to compare to so you can tell how much the MV has affected the
RV? Besides the manipulated variable, are all other variables kept the same (controlled)? What are these
controlled variables? What are the manipulated and responding variables of the experiment? What is the
hypothesis? Are there at least 3 trials so you can determine how consistent (reliable) the data is?
Can I follow (or write) their experimental steps (procedure) and are all parts included (such as multiple
trials and clear descriptions to set up the manipulated variable and keep other factors constant)? Did you
clearly indicate what to record for your responding variable (not just say “data”)?
Use the data : The test readers are looking to see if you quoted or referred back to specific data
pieces when you analyze results or write conclusions for the given experiments on the test. You must cite
data (averages are good to use) that covers the whole range (use at least the starting data and ending
data and describe the trend).
Take your time! This is not a timed test. You have time to organize thoughts or steps in procedures, and
to be sure you know all parts of the experiment before you answer. Do write inside the marked margins
though!