Biology I Final Exam Review
Topic 1 – Biodiversity
1. Describe the characteristics of living things and how they’re different from non-living things.
Living things use and obtain energy, store and transmit information, and have “containers”.
2. Compare the relative numbers of species that exist, have been named, and have ever existed on earth.
# Species on Earth
# named
# existing
# ever existed
3. Understand how biodiversity is organized by taxonomic classification and cladistics using organism’s
morphology, molecular comparisons, and fossils.
Taxonomic Classification
Kingdom, Phylum, Class, Order, Family, Group, Species. (King Phillip cries out for great seafood)
Classifying Biology
Morphology=form or shape
Molecular=studying DNA and proteins of an organism
Fossils=bone structure
Topic 2 - Evolution
Evolution
1. Outline what the fossil record is. Include how and where fossils form and the overall patterns in the history of
life on earth that emerge from studying the fossil record. Include reference to the major eras of geologic time
and periodic mass extinctions.
Fossils form when the remains of animals are trapped in sediments after their death and they either leave an
impression on the surrounding rock or their own bones become rock through fossilization.
Fossil Record
5000mya
4000
3000
2000
1000
0
Earth Formed
1st life (prokaryotes)
Photosynthetic bacteria
1st Multicelled 1st Animals
Homonids
4600 mya
3800 mya
2500 mya
life 1000 mya
2.5mya
Precambrian4600-570mya
Paleozoic550-240mya
Mesozoic240-65mya
Cenozoic65-1.65mya
480 mya
2. Make and interpret cladograms to show molecular and morphological evidence about species relationships.
Understanding Phylogenies
1
2
3
4
Recent
(34)
(1234)
(234
)
Past
Common Ancestors,
Speciation Events
3. Describe modern phylogenetics. What does a phylogenetic tree illustrate?
Modern phylogenetics allows us to make links and see the connections between different species on earth. A
phylogenetic tree illustrates the relationships between these species and just how closely species are related in
comparison to each other.
4. Outline Darwin’s contributions to the theory of evolution.
Darwin believed that evolution occurred through natural selection, all animals came from one common ancestor,
natural selection involves a struggle for survival, and that natural selection weeds out some traits while
reinforcing others.
5. Explain what ‘survival of the fittest’ means using a specific example.
Survival of the fittest means that those animals of a species which have the strongest combination of genes and
traits will survive over those with weaker combinations. For example, giraffes evolved their long necks through
this concept of natural selection. Once, all giraffes had relatively short necks, but some were slightly longer than
others. Those with slightly longer necks survived over those with slightly shorter necks as they could reach more
food. Those with shorter necks died and those with longer necks lived to breed, resulting in a greater percentage of
long necked offspring. The cycle continued until the giraffe evolved to the modern day result.
6. Explain what ‘descent with modification’ means in evolutionary terms.
Descent with modification means that as organisms with weak combinations of genes are weeded out before they
have a chance to breed, those with strong genes live to breed and their offspring inherit these strong genes. As
generations pass there is a change in gene frequency, with more of the stronger genes arising in the population.
7. Outline the many areas of evidence in addition to the fossil record that help illustrate the process of evolution,
including homologous structures, vestigial structures, molecular biology.
Wondering what evidence in cellular biology and biogeography help illustrate the process of evolution.
Homologous structures: wings in birds signify they all evolved from a common ancestor.
Vestigial structures: Whales have a vestigial hind limb, signifying that they evolved from an animal once walked
on land.
Molecular biology: Our DNA is 98% identical to those of Chimpanzees, signifying that we have a very recent
common ancestor.
Populations
1. Outline the importance of natural selection as a factor in evolutionary change.
Natural selection is extremely important for evolutionary change, because without it then there would be no
direction to evolution. Without the gradual decrease of some genes and the increase of others due to natural
selection, evolution would not be able to take place.
2. Describe the difference between disruptive, stabilizing, and directional selection.
Stabilizing evolution=a type of natural selection in which genetic diversity decreases as the population stabilizes
on a particular trait value (e.g. Human birth weight)
Directional evolution=when natural selection favors one trait and the species evolves more the that aspect than
any other
Disruptive evolution=changes in population genetics that favor individuals at both extremes of the distribution
3. Explain how sexual dimorphism tends to arise in sexually reproducing species.
Males and females tend to differ in sexually reproducing species as desirability in males is a genetic advantage,
and through natural selection those males deemed “more attractive” through certain traits by females will evolve.
4. Explain two ways that populations can be isolated and how that can lead to speciation.
Geographic isolation=a geographic factor such as a mountain range or river separates a species, causing them to
evolve independently for many generations, eventually resulting in different species.
Sexual isolation=potential mate does not pick up on any sexual ques given.
Human Evolution
1. Outline the traits of primates including humans.
Bipedal, opposable thumbs, eyes facing forward.
2. Describe the locations of, relative dates for and unique traits of Australopithecines, Homo habilis, Homo
erectus, Homo neanderthalensis and Homo sapiens.
Australopithecines=3-3.9mya, eastern and southern Africa, bipedal with apelike skull features but more humanlike
physique, marked sexual dimorphism.
Homo habilis=1.8-1.9mya, east Africa, larger brain size, bipedal, some sexual dimorphism.
Homo neanderthalensis=150,000-30,000years, Europe and Middle East, some sexual dimorphism, very large
brain size, robust stocky built, bipedal.
Homo sapiens=200,000years-present, worldwide (first found is Africa), very large brain, slight sexual dimorphism,
fully bipedal.
3. Describe the results of mitochondrial DNA and Y chromosome DNA in mapping the migration patterns and
dates of modern human (Homo sapiens) populations.
Mitochondrial DNA is used to trace female generations, Y chromosome DNA is used in tracing male generations.
4. Outline the major trends and overall pattern of human evolution and migration during the past 5 million years.
S. Africa 200,000years agoE. AsiaAustraliaEuropeAmericasPolynesiaNew Zealand.
Apple And Elephant Are Popular Nouns
Topic 3 – Heredity
Basic Inheritance
1. Define the following terms: chromososme, homologous, allele, gene, dominant allele, recessive allele, genotype,
phenotype, P1 generation, F1 generation, F2 generation, homozygous and heterozygous, pure breeding
Chromosome：tightly coiled packages of DNA located in nucleus.
Homologous: Homologous chromosomes are chromosomes containing information on the same genes (one from
mother one from father)
Allele: Alternate forms of genes.
Gene: Piece of DNA on a chromosome that expresses a protein.
Dominant allele: the allele that is expressed over the recessive allele for a trait.
Recessive allele: an allele that will be expressed if not masked by a dominant allele for the same gene.
Genotype: genetic identity of an individual that does not show as outward characteristics.
Phenotype: the physical appearance expressed by the genotype of an individual.
P1 generation: Parental generation
F1 generation: First filial generation
F2 generation: Second filial generation
Homozygous: Same two alleles for same gene
Heterozygous: Two different alleles for same gene
2. Select and/or recognize suitable allele symbols for single-gene crosses, based on the characteristics of the alleles.
1. Construct and analyze Punnett squares to illustrate probable outcomes of single-gene crosses showing simple
dominant/recessive alleles.
AA+Aa= 50%AA, 50%Aa. All express “A” trait.
A
A
A AA
AA
a
Aa
Aa
2. Explain the use of a test cross to find the genotype of an individual with a dominant phenotype.
Breed the individual with another that expresses a recessive gene (hence being homozygous). If the offspring
express both recessive and dominant genes, then the individual was heterozygous, if the offspring expresses only
dominant gene, the individual is homozygous with dominant gene.
Sources of Variation: Meiosis and Independent Assortment
1. Outline the role of meiosis in the production of haploid [n] gametes from diploid [2n] parent cells.
Meiosis produces four haploid cells from each diploid parent cell. Each haploid cell has only 1 allele for each trait,
ready to merge with the matching allele from the haploid cell of a mate.
2. State the number of daughter cells made as a result of meiosis.
Four.
3. Draw and label and/or interpret simple diagrams of the stages of meiosis.
Interphase, Prophase, Metaphase, Anaphase, Tetraphase. (Indians play madly and terrifically)
Interphase: cell enlarges, chromosomes duplicate, centrioles duplicate, chromosomes wind up, nucleus
disappears.
Prophase 1: Chromosomes become visible, crossing over of chromosomes expressing same genes occurs
(parental and maternal), nucleus disappears, spindle network forms.
Metaphase 1: pairs of chromosomes migrate to the middle of cell and align on metaphase plate. Spindle fibers
attach. The way chromosomes line up is very important because it determines the traits of four future haploid
cells.
Anaphase 1: homologous chromosomes are pulled apart by spindle fibers and migrate to opposite sides of cell.
Tetraphase1: Homologous chromosomes reach poles of cell, nuclear envelop forms around them, cytokinesis follows
to produce two cells.
Prophase 2: Meiosis 2 begins without any further replication of the chromosomes. In prophase 2 the nuclear
envelop breaks down and spindle network forms.
Metaphase 2: chromosomes become arranged on the metaphase plate, now attached to spindles.
Anaphase 2: The centrometers separate and the sister chromatids-now individual chromosomes, move towards
opposite poles of the cell.
Tetraphase 2: A nuclear envelop forms around chromosomes, cytokinesis occurs, four daughter haploid cells
produced.
4. Explain the need for haploid gametes in sexual reproduction.
Haploid gametes are needed because only one allele for each gene is stored in them, when they merge with mate’s
haploid gamete, then the matching chromosomes come together and parental and maternal alleles are combined.
5. Describe the laws of segregation, independent assortment, and random fertilization, and explain their role in
creating new phenotype possibilities each generation.
Laws of segregation: The separation of the homologous chromosomes and their random distribution to the
gametes at meiosis.
Independent assortment: formation of random combinations of chromosomes in meiosis
Random fertilization: egg and sperm can contain any combination of chromosomes, no one know which sperm
and egg will become fertilized.
Jumbles up parental and maternal alleles for different chromosomes, so offspring contains both
grandfather and grandmother’s alleles from both parents.
Complex Patterns in Inheritance
1. Construct and analyze Punnett squares to illustrate probable outcomes of single-gene crosses showing multiple
alleles, codominant alleles.
1. Construct and analyse Punnett squares to illustrate probable outcomes of single-gene crosses. These include
simple dominant/recessive alleles, incomplete dominance, multiple alleles [blood groups], co-dominance and
sex-linked alleles.
2. Calculate genotype and phenotype ratios from such crosses.
Simple dominant/recessive alleles
AA+Aa= 50%AA, 50%Aa. All express A trait.
A
A
A AA
AA
a
Aa
Aa
Incomplete dominance
AB+AB=50%AB, 25%AA, 25%BB.
A
B
50% incomplete dominance AB, both traits expressed (e.g. pink flower)
A AA AB
25% AA, A trait expressed (e.g. red flower)
B AB BB
25% BB, B trait expressed (e.g. white flower)
Multiple alleles [blood groups]
IAIB+ IA i=25% IA i, 25% IB i, 25% IAIA, 25% IAIB
IA
IB
25% heterozygous A blood
i IA i IB i
25% heterozygous B blood
IA IAIA IAIB 25% homozygous A blood
25% heterozygous AB blood
Cancer, Genetic Disorders, and Epigenetics
1. Explain what cancer is and describe the progression of mutations that typically leads to cancer. Include
proto-oncogenes, oncogenes, tumor-suppressor genes.
Cancer is a disease where a cell is no longer following “rules” on how often they reproduce. Malfunction in signaling
process where cells don’t know when to stop dividing.
Caused by mutation of genes:
 Proto-oncogenes: An oncogene before it is active.
 Stability: “incompetent car mechanic” is supposed to suppress mutations
 Tumor suppressor genes: “breaks” tries to stop cell division.
 Oncogenes: Turns on cell division, makes a cell divide over and over.
2. Explain how factors beyond the order of the DNA bases can influence the expression of traits using an
example.
Epigenome: decides how genes are expressed. Consists of genetics switches and markers that turns genes “on”
and “off”. E.g. the agouti mice were fed a methyl rich diet, resulting in some of their offspring not being obese or
yellow. This means that the agouti gene is methylated in the skinny brown mice, and unmethylated in the obese
yellow mice.
3. Describe the nature/nurture debate as it relates to observations of epigenetic effects.
Both inherited genetics and personal environment and choices are inexplicably linked through the epigenome.
What your mother or even grandmother or father were exposed to in their lifetime may have an influence on your
personal epigenome and trait expression.
Topic 4 – DNA Unit
Nucleic Acids
1. Describe and draw a simple labeled diagram of a DNA nucleotide.
Phosphate
5’
Sugar
Hydrogen Bonds
Base
3’
2. Describe and draw a simple labeled diagram of a short section of a DNA molecule.
3. Identify three and five prime ends of each half of a DNA strand
The one with the phosphate is 5’ the one without is 3’.
4. List the three main types of RNA and their functions.
 mRNA or messenger RNA is the RNA produced by the transcription. It is the strand that breaks off and sends
message to ribosomes for protein synthesis.
 rRNA is the variety of RNA that combines with different proteins to form ribosomes.
 tRNA or transfer RNA are short RNA sequences that bring amino acids to ribosomes to code with mRNA
during protein synthesis.
5. Compare and contrast the structure and function of DNA and RNA, including number of polynucleotide
chains, sugar type, bases used and overall length.
RNA does not have a double helix structure, only one polynucleotide chain as opposed to the two chains that DNA
has. RNA is significantly shorter than DNA, only containing the number of codons that are needed to form the specific
protein instructed.
6. Compare the structure and function of the tRNA and mRNA.
tRNA bring amino acids to the mRNA that is attached to the ribosome, the tRNA codes with the mRNA and the
polypeptide chain of amino acids is formed.
DNA replication
1. Describe how and where DNA replication takes place, including the role of DNA helicase, DNA polymerase
and free DNA nucleotides and complementary base pairing.
During DNA replication the first step is when a group of DNA enzymes attach to the DNA and it unwinds as the
DNA helicase breaks hydrogen bonds. The DNA polymerase then travels along the template strand from 3’ to 5’
side, recognizes unpaired base and attracts the correct complimentary nucleotide. This is complimentary base
pairing. Once all pairs have been matched, the DNA has been successfully replicated.
2. Make and/or interpret simple labeled diagrams to explain DNA replication
3. Define what is meant by semi-conservative replication.
Each strand acts as a template for a new double helix. The established model of DNA replication in which each
double-stranded molecule is composed of one parental strand and one newly polymerized strand.
Protein synthesis
1. Define the terms codon, anticodon, start codon, stop codons, transcription, translation, amino acid,
polypeptide, protein.
Codon: In DNA or RNA, a sequence of three nucleotides that codes for a certain amino acid or signals the
termination of translation (stop or termination codon)
Anticodon: The sequential set of three nucleotides in tRNA that interacts with its complement in mRNA, the
codon, during translation in the ribosome.
Start codon: codon at the beginning of an RNA strand that causes translation to begin.
Stop codon: ends translation and polypeptide chain.
Transcription: The process of copying information from DNA into new strands of messenger RNA (mRNA). The
mRNA then carries this information to the cytoplasm, where it serves as the blueprint for the manufacture of a
specific protein.
Translation: The process of turning instructions from mRNA, base by base, into chains of amino acids that then
fold into proteins. This process takes place in the cytoplasm, on structures called ribosomes.
Amino acid: Any of a class of 20 molecules that are combined to form proteins in living things.
Polypeptide: Any compound consisting of two or more amino acids, the building blocks of proteins. Peptides are
combined to make proteins.
Protein: A molecule made up of amino acids that are needed for the body to function properly.
2. Describe the role of the enzyme RNA polymerase in transcription.
RNA polymerase breaks hydrogen bonds just above an active gene and attracts complimentary nucleotide bases to
from the mRNA strand.
3. State the locations, within the cell, of the processes of transcription and translation.
Transcription: nucleus
Translation: cytosol
4. Describe the roles of mRNA, tRNA and ribosomes in translation.
mRNA is the strand that acts as the blueprint for forming the polypeptide chain of amino acids.
tRNA brings amino acids to the mRNA strand during translation and codes with correct triplets.
Ribosome moves along the mRNA chain, forming the polypeptide chain as the tRNA brings in amino acids and
code with mRNA.
5. Describe how the information in the template DNA strand codes for a specific polypeptide.
The template DNA strand codes with free nucleotides to form a mRNA strand, which is then translated into a
chain of amino acids carried by the tRNA.
6. Use a translation table to show how information on mRNA determines a specific order of amino acids to make
a polypeptide molecule.
DNA
TAC
TTC
CAG
GGG
ATG
CCT
TAA
ACG
TAC
mRNA
AUG
tRNA
UAC
anticodon
Amino
Initiation
acid
codon
AAG
GUC
CCC
UAC
GGA
AUU
UGC
AUG
UUC
CAG
GGG
AUC
CCU
UAA
ACG
UAC
Lysine
Valine
Proline
Tyrosine
Glycine
Isoleucine Cysteine
Methionine
Gene mutations
1. Define, and give examples of, the term gene [point] mutation. This should include deletion, insertion and
substitution.
Gene point mutation is when one nucleotide in a gene is changed.
Deletion is when the nucleotide is deleted altogether
Insertion is when one extra base is inserted
Substitution is when one base is substituted for another
2. Predict the effects of “frameshift” gene mutations on protein synthesis.
Frameshift gene mutations can be disastrous for protein synthesis because it results in a shift and a whole new
sequence of codons. This usually results in a non-functional protein
3. Outline the cause and effect[s] of gene mutation.
Effects of gene mutation include dysfunctional proteins or proteins that carry out the wrong functions.
Topic 5 – Human Impact on Biodiversity
1. Explain why preservation of biodiversity is important.
Four “E”s
 Ecological- all species are interconnected, removal of one may cause ecological collapse.
 Economical- nutrient cycling, photosynthesis, clearing waste, filtering water, stabilizing climate already occurs
naturally due to biodiversity.
 Ethical- all species have inherent right to live, we should pass a diverse world onto our offspring.
 Aesthetic- the biodiversity of the world is beautiful.