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What is DNA, what does it stand for, and what is the structure of DNA? Label the diagram.
genetic material. stands for deoxyribonucleic acid. structure is a double helix
Draw and label the parts of a nucleotide.
What are the base pairings for DNA? For RNA?
dna → adenine with thymine; guanine with cytosine
rna → adenine with uracil; guanine with cytosine
Describe the following types of gene mutations: substitution, deletion, and inversion.
substitution: substitutes a base for another
deletion: deletes a base
inversion: base segment breaks off and reattaches within the same chromosome, but in reverse orientation
What is replication?
in nucleus. uses dna.
the opening of the double helix and separation of the dna strands
the priming of the template strand
and the assembly of the new dna segment
results in two identical strands of dna
What is transcription?
nucleus. uses dna.
initiation: helps eukaryotic rna polymerase recognize promoter sequences
elongation: rna polymerase unwinds dna and adds nucleotides to the 3’ end of the rna chain
termination: when the rna polymerase encounters the termination signal, the rna transcript is released
results in mrna
What is mrna processing?
in nucleus. uses mrna.
5’ end gets a modified nucleotide cap. 3’ end gets a poly-a tail (protection as it goes through the cell)
introns (toss) are removed to produce mrna (keep exons)
to make a functional molecule that performs & looks correct for its job
results in rna
What is translation?
in ribosomes. uses rna.
initiation: brings together mrna, trna bearing the first amino acids of the polypeptide and two subunits of a ribosome
elongation: amino acids are added one by one to the preceding amino acids
termination: when the ribosome reaches a stop codon in mrna, ribosomes binds with a release factor (protein), everything starts disassembling
results in polypeptide/ protein
Name and explain the 3 steps of PCR. What is PCR used for?
used to replicate copies of a specific dna sequence in a few hours
denaturation of the template into single strands
annealing of primers to each original strand for new strand synthesis
extension of the new DNA strands from the primers
What is gel electrophoresis? What is it used for?
a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size
used to determine genetic disorders, identity or individuals
What is a GMO? Name and explain 2 benefits and 2 disadvantages to their use and propagation.
genetically modified organisms
benefits: 1) development of disease-resistant plants 2) can degrade environmental pollutants
disadvantages: 1) immuno-suppression 2) antibiotic resistance
What is a clone? How are clones produced?
genetically identical copies of genes or entire organisms
an unfertilized egg is taken from an animal and the nucleus is removed. the nucleus from a cell of an egg to be cloned is inserted and stimulated to divide
What is the outcome of meiosis?
division of a diploid parent cell into haploid progeny
What happens during each of the phases of Meiosis?
Prophase I → homologs pair up. crossing over
Metaphase I → independent assortment
Anaphase I → homologs separate & chromosome # is halved (diploid → haploid)
Telophase I → chromosomes have finished moving to opposite ends of the cell
Prophase II → the phase that follows after meiosis I, or after interkinesis if present
Metaphase II → the centromeres of the paired chromatids align along the equatorial plate in both cells
Anaphase II → sister chromatids separate. separation doesn’t affect ploidy
Telophase II → final outcome is four cells, each with half of the genetic material found in the original
Define the following and include chromosome number for each in humans:
haploid (n): half of diploid. only gametes
dipoid (2n): full set of chromosomes. humans → 46. only somatic cells
Explain how gametogenesis differs in males and females.
males do it their entire lives, while females are already made when they are born (finite)
Who is the Father of Genetics?
Gregor Mendel, an australian monk
Define and give an example of the following terms: gene, allele, and trait.
gene: a charitable factor that has a specific characteristic
allele: alternate forms of a gene, use letters to represent
trait: phenotypic characteristic of an organism
What does it mean if a trait is considered dominant? What does it mean if a trait is considered recessive?
if dominant, a trait that covers over, or dominates, another form of that trait. if recessive, the trait of an organism can be masked by the dominant form of a trait
Explain the difference between homozygous and heterozygous
homozygous → same allele (DD or dd)
heterozygous → different allele (Dd)
How are alleles represented for a homozygous dominant trait? Homozygous recessive trait? Heterozygous trait?
DD; dd; Dd
Explain the difference between codominance and incomplete dominance. Give an example of each.
codominance: alleles are equally dominant. stripes or polka dots
incomplete dominance: one allele isn’t completely dominant. blending of alleles
Define polygenic traits and provide an example.
one trait is characterized by the interaction of several genes. ex: human skin color (6 genes), human eye color (3 genes)
What are karyotypes used for? In other words, what type of information can they give you?
chromosome mapping. can show chromosomal abnormalities, sex, and # of chromosomes
What genetic disorder is Trisomy 21 commonly known as? How does this disorder occur?
down syndrome. occurs when a person has an extra copy of chromosome 21
What is a pedigree, and what do the symbols represent? What does a shaded symbol represent?
a chart that can help trace a trait or disease in a family. box: males; circle: female. shaded means it carries the trait
Explain the Oxygen Revolution and why it was important to the evolution of complex life on Earth.
cyanobacteria produced O2 via photosynthesis about 200 bya; algae and plants followed. aerobic respiration could now take place → more atp is made. different types of organisms could now evolve
What were the first organisms on Earth like?
performed anaerobic respiration (no O2) and heterotrophs
What evidence did Darwin use to support his theory of evolution by natural selection?
fossil evidence, biogeographical evidence, and anatomical evidence
What is an adaptation? Give an example.
any trait that aids the chances of survival and reproduction of organisms. ex: fur, feathers, fat, long legs, camouflage
Explain speciation. What factors lead to speciation?
the forming of a new and distinct species due to evolution. factors are geographical barrier, natural selection, and genetic drift
Compare and contrast analogous, homologous, and vestigial structures. Which ones can be used to support evolution and which ones cannot?
analogous: have a similar structure but no ancestry involved; due to convergent evolution (same function, different structure). provides evidence for evolution
homologous: body parts arising from the same embryonic tissues; due to divergent evolution (same structure, different function). provides evidence for evolution
vestigial: structures that have no function in the living organism. provides evidence for evolution
Explain why mules and ligers are not considered to be distinct species.
they are infertile and can’t breed together
What is artificial selection? Give an example.
humans choosing the traits they determine to be advantageous or preferable
Explain Hardy-Weinberg Equilibrium. MAKE SURE YOU CAN SOLVE HWE PROBLEMS USING THE EQUATION!
a population’s genetic variation will remain constant with no disturbances in population. (make sure to solve for homozygous recessive first!)
What do the variables p and q refer to in the Hardy-Weinberg Equation?
p → frequency of dominant allele
q → frequency of recessive allele
What do the variables p2, 2pq, and q2 refer to in the Hardy-Weinberg Equation?
p2 →homozygous dominant
2pq → heterozygous
q2 →homozygous recessive
Define all the parts of a cladogram – sister taxa, clade, and derived character.
What is a dichotomous key and how is it used to classify organisms?
an important scientific tool, used to identify different organisms, based on the organism's observable traits. consists of a series of statements with two choices in each step that will lead users to the correct identification
Is a virus considered to be a living organism? Why or why not?
no. aren’t made of cells, they can't keep themselves in a stable state, they don't grow, and they can't make their own energy
What is binomial nomenclature? Who developed this method of naming organisms?
two word naming system made by Carolus Linnaeus
What are the levels of classification from broadest (most inclusive) to most specific (least inclusive)?
domain, kingdom, phylum, class, order, family, genus, species
Complete the chart to explain the following plant adaptations.
phototropism: growth of an organism in response to a light stimulus. will grow towards the light. ex: plant bending towards window
gravitropism: the growth response of a cell or an organism to gravity. roots will grow towards gravity and the stem will grow away from gravity
thigmotropism: the directional growth of a plant, in response to the stimulus of direct contact. ex: venus fly traps and vines growing on buildings
Complete the chart about the 6 kingdoms of life.
archaebacteria: unicellular, prokaryotic, autotrophic and/or heterotrophic, no peptidoglycan in the cell wall. unusual group of lipids make up the cell membrane
eubacteria: multicellular, prokaryotic, autotrophic and/or heterotrophic, “true bacteria”
protista: most are unicellular, some are multicellular or colonial cellular, eukaryotic, autotrophic and/or heterotrophic, some cell walls contain cellulose. some have chloroplasts.
fungi: multicellular except yeast, eukaryotic, heterotrophic, cell walls have chitin. many are decomposers.
plantae: multicellular, eukaryotic, autotrophic, cell walls have cellulose.
animalia: multicellular, eukaryotic, heterotrophic, no cell walls or chloroplasts
Give an example of a biotic factor and give an example of an abiotic factor.
biotic factor: soil & animal dung
abiotic factor: water temperature
What are three types of symbiotic relationships? Give an example of each.
mutualism: +/+. ants, acacia trees, and butterfly caterpillars
commensalism +/0. phoretic mites on damselflies
parasitism: +/-. heartworms and humans
What are keystone species? Provide an example.
species that keep an ecosystem together. ex: beavers and prairie dogs
Explain the four trophic levels in an ecosystem. Explain how each level obtains energy. Explain what type of consumers (herbivore, carnivore, omnivore, and detritivores) would be at each level.
producers: obtain energy from the sun
primary consumers: obtain energy from producers. usually herbivores
secondary consumers: carnivores or omnivores that obtain energy from primary consumers
tertiary consumers: carnivores or omnivores that obtain energy from secondary consumers
apex/quaternary consumers: carnivores that obtain energy from tertiary consumers
decomposers: detritivores and decomposers that obtain energy from decomposing organisms
What is the average ecological efficiency of most ecosystems? In other words, how much energy gets passed from one trophic level to the next? Why is the number so low?
10%. 90% is lost to the environment
How would this food web be impacted if the small planktivorous fish were removed?
zooplankton would increase. large piscrivorus fish, wading birds, gulls and tems populations would decrease due to lack of small planktivorous fish. osprey populations would decrease since they only eat large piscivorous fish.
Explain the process of succession and distinguish between primary and secondary succession.
primary succession: takes the longest. starts with rocks turning to soil. starting from scratch. starts with lichen or mosses. secondary succession: damaged ecosystem but the soil is left intact. less time needed.
Explain the difference between logistic and exponential growth. Draw a graph depicting each.
logistic growth: occurs with limited resources and population has a slow growth rate until carrying capacity is reached
exponential growth: occurs when resources are abundant and a population size increase very rapidly
What is the difference between a renewable and non-renewable resource? Give an example of each.
renewable resources are regenerated as soon or quickly after they are used. ex: coal and oil
non-renewable resources are regenerated long after they are used. ex: water and solar
Explain the reproductive strategies of organisms with a Type I, Type II, or Type III survivorship.
type i: late loss, high survivorship throughout life. few amount of offspring
type ii: constant loss, independent of age. medium amount of offspring
type iii: early loss, low mortality after maturity. lots of offspring
Differentiate between density-dependent limiting factors and density-independent limiting factors.
density-dependent limiting factor: are affected by the number of individuals in a given area (competition, predation, parasitism, disease)
density-independent limiting factor: are aspects of the environment that can affect a population regardless of its size (unusual weather, natural disasters, human activities)
Explain the Nitrogen Cycle.
the nitrogen cycle is the process by which nitrogen is converted into different forms that can be used by living organisms. nitrogen fixation is the process by which nitrogen gas is converted into ammonia by bacteria. ammonia is then converted into nitrate by bacteria in a process called nitrification. plants can then assimilate the nitrate and use it to build proteins. when organisms die, decomposers break down the proteins and release ammonia back into the soil. denitrification is the process by which bacteria convert nitrate back into nitrogen gas, which is released into the atmosphere.
In what way are humans most impacting the Carbon Cycle?
breathing, burning fossil fuels, changing land use, and using limestone to make concrete
Explain biomagnification.
occurs when a pollutant moves up a food chain and accumulates in higher concentrations in the bodies of predators.
Explain some ways that humans can help the environment.
sustainable development, protecting umbrella species, and creating conservation acts
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