2015 CHHS Science Gateway Study Guide Packet
Remember to eat breakfast. Bring a pen, pencil, highlighter, and calculator (not graphing). Discuss and cite all
documents as well as provide your own prior knowledge.
ECOLOGICAL CHANGES
Bottom Line: Ecological changes refer to the growth or regrowth of species in an ecosystem over time. A common term associated
with this concept is ecological succession. In ecological succession, the trend is an ecosystem moves from early stages where only
pioneer species, such as small plants, mosses and lichen, towards its climax community, which is the stable, full grown variety of
species characteristic for its biome. There are two types of ecological succession – primary succession and secondary succession. In
primary succession, an ecosystem starts from nothing – even soil has to be made by pioneer species like moss and bacteria
decomposing organic material. In secondary succession, an ecosystem that has been establish is disrupted by a natural disaster or
human activity and must regrow with any remaining species and soil already present. In either type of succession, once plant life
has been (re)established, animal life can be sustained through the food chain.
Vocabulary:
ecosystem: all the biotic (living) and abiotic (non-living) factors interacting in an area; ex: trees, soil, moisture and squirrels in a field.
community: all the different living species (biotic factors) interacting in an area; ex: mice, coyote and humans interacting.
ecological succession: series of changes that occur in an ecosystem over time typically moving from pioneer stage to climax
community stage.
pioneer species: species that first inhabit an area in succession; typically small autotrophs that better conditions for species which
later inhabit the area; examples: lichen, mosses, small plants
climax community: fully grown, stable variety of species that is characteristic of the biome for an area; ex: hardwood deciduous
forest in Georgia
habitat disruption: an act that changes the number and type of species in an area; ex: forest fires, flood, pollution
primary succession: type of ecological change process in which an area starts with no life or soil and develops into a functioning
ecosystem; ex: volcanic lava cools in the ocean to form lifeless rock; eventually pioneer species like algae and mosses, carried by
currents, inhabit the rock; their breakdown eventually makes soil and more life can migrate or be carried to the rock habitat.
secondary succession: type of ecological change process in which an ecosystem that is already established is disrupted and must
regrow with the remaining species; ex: a forest fire burns many trees and grasses leaving some species to regrow; pioneer species
include small plants and grasses.
Video Notes: http://www.youtube.com/watch?v=V49IovRSJDs
Example Prompt: In 1980, a forest fire burned 100 acres of a hardwood oak and hickory forest community in Gwinnett County. By
2012, much of that 100 acres is now covered in pine trees, tall grasses and a few young hardwood trees. Few deer, squirrel and field
mice have also repopulated the land. Using your knowledge of ecological succession, discuss the following:
-What type of succession applies to this scenario? Support your answer.
-What type of pioneer species likely inhabited this area after the fire? What was their role?
-Has the 100 acres reached its climax community? Support your answer.
Biochemistry/Nutrition
Bottom Line: If you’ve heard the term, you are what you eat, this is true to some degree. The foods we eat contain proteins, lipids
and carbohydrates, which are all types of organic macromolecules or polymers we use for energy and to repair and replace our cells
and tissues. Nutrition is twofold: get the energy from breaking down the bonds in food to power our bodies (by recharging a
molecule called ATP) and get the building blocks (monomers) of materials we need to grow and repair our bodies.
Vocab:
Organic: Molecule containing carbon
Macromolecules: Large molecules with many atoms that make up foods and the structure of living things; include proteins, lipids,
carbohydrates and nucleic acids.
Proteins: organic macromolecule made up of amino acid monomers (elements C, H, N, O, P, S); provides energy when broken down,
makes up structure of muscle, skin and makes up enzymes which catalyze reactions in the body
Lipids: organic macromolecule made up of triglyceride monomers (elements C, H, O); provides energy when broken down; makes up
structure of cell membrane and cholesterol; also cushions and insulates the animal body; lipids are how animal bodies store energy
(fat)
Carbohydrates: organic macromolecule made up of monosaccharide monomers (elements C, H, O); preferred source of energy for
the body; plants store energy as polysaccharides such as starch.
Hydrolysis: Reaction in the body using water and enzymes to break down food.
Polysaccharide
Polypeptide
Video Notes: Molecules of Life - http://www.youtube.com/watch?v=QWf2jcznLsY
Video Notes: Digestion - http://www.youtube.com/watch?v=nM5kMSjBrmw
https://www.youtube.com/watch?v=G0O87gWv-Xk
https://www.youtube.com/watch?v=MnnfN5BIX7E
https://www.youtube.com/watch?v=FbaXQ8u6IP8
Example Prompt: Discuss the saying “you are what you eat” in terms of the following:
-What role does digestion play in homeostasis?
-What are the 3 organic macromolecules found in our foods?
-What are the functions of the macromolecules we consume in our bodies?
Energy Transformation
Bottom Line: Cells must conduct different processes to obtain energy and materials, excrete waste and divide for various purposes.
Watch the following videos and jot down how these processes help the cell maintain their function and homeostasis.
Vocab:
Chloroplast: the part of the cell containing the chlorophyll where photosynthesis takes place
Mitochondria: the part of the cell where food is converted to energy during cellular respiration
10% Rule of Energy Flow: only 10% of the organisms energy can be passed on to the next organism in the food chain when it is
consumed. The remaining energy is used or given off as heat.
Equation for Photosynthesis: 6CO2 + 6H2O + sunlight ---> C6H12O6 + 6O2 (only occurs in plant cells) this reaction occurs in the
chloroplast and is endothermic because it uses energy
Equation for Respiration: C6H12O6 + 6O2 ---> 6CO2 + 6H2O + ATP (occurs in both plant and animal cells) this reaction is exothermic
because it produces energy (ATP)
Heterotrophs: Obtain energy and nutrients from the food they eat
Autotrophs: Obtain energy from the sun and from nutrients from the soil.
Producer: Uses energy from the sun and carbon from the environment to make its own food. “Bottom of the food chain” Necessary
in any ecosystem because they make energy from the sun available/usable for heterotrophs.
Consumer: Obtains energy through eating other organisms
• Herbivore: eats only plants
• Carnivore: eats only animals
• Omnivore: eats both plants and animals
– Primary consumer: eats producers
– Secondary consumer: eats the consumers that eat the producers
Means of obtaining nutrition:
Predation: Ecological interaction in which one organism (predator) feeds on another living organism(prey).Predator may or may
not kill the prey.
Scavenging: An animal ingests dead plants, animals, or both. Ex: Vultures, termites, beetles
Food Chain: Linear pathway of energy transport through an ecosystem. Ex: algaekrillcodsealkiller whalebacteria.
Producers always come first in the food chain. Decomposers always come last in the food chain; they will break down dead
organisms and allow nutrients to be recycled. Arrows indicate the direction in which energy flows through the ecosystem.
Bacteria/Decomposers
Video Notes: Photosynthesis & Respiration http://www.youtube.com/watch?v=0IJMRsTcwcg
Example Prompt – How does light energy transform into chemical energy and flow in an ecosystem?
Genetics (Mendelian)
Bottom line: Alleles are types of genes (segments of DNA) carried on chromosomes that determine traits of an organism by coding
for proteins. Mendelian genetics, named after the work of Gregor Mendel, describes traits that are controlled by
dominant/recessive alleles. Mendel concluded that factors, now called alleles, are passed and not altered each generation (Law of
Unit Characters), each parent only passes on 1 allele per trait (Law of Segregation), a dominant allele masks a recessive allele (Law of
Dominance) and alleles randomly assort when passed (Law of Independent Assortment).
Genotype refers to the allele combinations an individual inherits, written as single letters – a capital letter (ex: T) stands for a
dominant allele and a lower case letter (ex. t) stands for a recessive allele. A dominant allele will mask the recessive allele and
produce the dominant trait or phenotype. An example of a Mendelian trait is tongue rolling (in a hot dog shape). Tongue rolling is
the dominant phenotype. Not being able to roll one’s tongue is the recessive phenotype. Homozygous dominant genotypes (ex: TT)
and heterozygous genotypes (Tt) both produce dominant phenotype of tongue rolling. Only the homozygous recessive genotype (tt)
produces the recessive phenotype of non-tongue rolling. Punnett squares are tools we can use to predict inheritance of traits from
offspring based on parent genotypes.
Vocabulary:
allele: single gene which codes for a trait; Ex: T = dominant allele for tongue rolling
genotype: two allele combination which controls the phenotype an organism has; Ex: Tt is a heterozygous genotype which produces
the dominant, tongue rolling phenotype
phenotype: physical trait expressed by an individual’s inherited genotype; ex: tongue rolling, brown eyes, red hair
dominant allele: allele that masks a recessive allele (Ex: T); produces dominant phenotype
recessive allele: allele that is masked by a dominant allele (Ex: t); the recessive phenotype is only seen in the homozygous recessive
genotype
homozygous dominant: genotype of two dominant alleles (TT); produces dominant phenotype
heterozygous: genotype of one dominant and one recessive allele (Tt); produces dominant phenotype
homozygous recessive: genotype of two recessive alleles (tt); produces recessive phenotype
P1: first parents crossed
F1: first offspring generation, offspring of the P1 cross
Video Notes: http://www.youtube.com/watch?v=NWqgZUnJdAY
Example Prompt: Two purple flower pea plants in the P1 generation are crossed and produce 100 offspring in the F1 generation. Of
the F1 offspring, 71 have purple flowers and 29 have white flowers. Based on the information, discuss the following:
-How are traits, like flower color, in this scenario passed from parent to offspring?
-In this scenario what are the dominant and recessive phenotypes, support your answer
-Based on the information, what must have been the genotypes of both parents in the P1
-Work a punnett square showing the P1 generation and F1 outcomes and compare to the results in the scenario
Genetics (Central Dogma of Molecular Biology)
Bottom Line: Genetics is a BIG topic! The “central dogma of molecule biology” describes the process of how DNA controls traits. It
is commonly remembered as DNA  mRNA  amino acid sequence  protein  trait. Therefore any process in between DNA and
trait (and beyond) applies to GENETICS. The following vocabulary and video will give a quick review of the topics.
Vocabulary:
DNA: Deoxyribonucleic acid; made double helix up of nucleotides of deoxyribose sugar, phosphate group and a nitrogen base (A, G,
T, C); it is the nitrogen base that contains the information.
Replication: Process by which DNA is copied during the S phase of the cell cycle; DNA splits and makes two templates; enzyme DNA
Polymerase matches complementary base pairs to each template leaving a semi-conservative copy of DNA; Ex: DNA template =
TTGCCG then DNA Polymerase will bring in AACGGC; in DNA A pairs with T and C pairs with G
RNA: Ribonucleic acid; made up of nucleotides of ribose sugar, phosphate group and nitrogen base (A, G, U, C); single stranded
unlike DNA; In RNA A pairs with U and C pairs with G
Transcription: Process in protein synthesis whereby DNA’s message is made into an mRNA transcript using the enzyme RNA
Polymerase in the nucleus; Ex: DNA template = TTGCCG then RNA Polymerase will make a complementary message of UUCGGC
which can leave the nucleus. Using an mRNA codon chart, we can decode which amino acids each 3 letters of mRNA (called a codon)
stand for in making up a protein.
Translation: Process in protein synthesis whereby mRNA’s message is decoded by tRNA at the ribosome and proteins are made; Ex:
If mRNA is GGC, the amino acid Glycine will be brought in by the tRNA with the anticodon GGC
mRNA: messenger RNA; takes an RNA copy of DNA’s message from the nucleus to the ribosome
tRNA: transfer RNA; decodes mRNA at the ribosome and brings the correct amino acid to the protein being made
amino acid: monomer of a protein; there are 20 different amino acids specified for by mRNA codons in living things
mutation: change in the DNA code which may alter the protein produced and produce a different trait; ex: DNA sequence of a
normal gene = TACAAA; a mutated gene may have a sequence TACTAA, changing the amino acid sequence of the protein.
sex-linked trait: trait who’s allele is carried on either the X or the Y chromosome; these types of traits are exceptions to Mendel’s
Laws; ex: colorblindness and hemophilia; X linked traits are passed from fathers  daughters and from mothers  sons or
daughters; Y linked traits (which there are very few) are only passed from fathers  sons
Video Notes: https://www.youtube.com/watch?v=itsb2SqR-R0&list=PL3EED4C1D684D3ADF&index=12 OR
http://www.youtube.com/watch?v=h3b9ArupXZg
Example Prompt: A male patient is colorblind. Neither of his parents are colorblind, but his mother’s father was. The colorblindness
allele on his X chromosome has the DNA sequence TACAAATAGACT. The allele for normal vision is TACAAACAGACT. Discuss the
following:
-Describe how the male patient inherited his colorblindness if neither of his parents have the trait.
-Describe how DNA controls traits using the “central dogma of molecular biology”
-How does a change in DNA code result in a different trait?
Cell Structure and Function
Bottom Line: There are many different types of cells. The most commonly recognized types of cells are prokaryote and eukaryote.
Bacteria are prokaryotes. Prokaryotes have ribosomes, a cell membrane and a cell wall but lack a nucleus and certain membrane
bound organelles. Plants, Animals, Fungi and Protists are all made up of Eukaryotic cells. These types of cells have a nucleus and
membrane bound organelles.
Video Notes: http://www.bozemanscience.com/a-tour-of-the-cell
Vocab Activty
Prokaryote/Eukaryote Venn Diagram – Fill In
Membrane Bound Organelle:
Nucleus:
Ribosomes:
Cell Membrane:
Cell Wall:
Golgi
ER
Lysosomes
DNA
Example Prompt: A younger student thinks there are only 2 types of cells: plant and animal. Explain to the student that there are
more types of cells. Be sure to address:
-A description of prokaryotic cells
-The similarities and differences of prokaryotic and eukaryotic cells
-Which type of cell makes up plant and animal cells