Final Exam Review - KEY
Chromosomes, Mitosis & Meiosis
Vocab
Chromatid: one half of a chromosome
Centromere: center of a chromosome that hold sister chromatids together
Mitosis: process of making identical copies of cells
Prophase: nucleus disappears, chromosomes form, organelles disappear, centrioles move to opposite
ends of the cell
Metaphase: chromosomes line up in the middle of the cell
Anaphase: chromosomes split apart into chromatids
Telophase: two new nuclei form, chromosomes break down into chromatin, organelles reappear
Cytokinesis: cytoplasm splits into two new cells
Interphase: growth of cell, organelles replicate, DNA replicates
Prophase I: nucleus disappears, chromosomes form and tetrads pair up, organelles disappear, centrioles
move to opposite ends of the cell, crossing over takes place
Metaphase I: tetrads line up in middle of cell
Anaphase I: tetrads separate into chromosomes
Telophase/Cytokinesis I: two new nuclei form, break down into chromatin, organelles reappear,
cytoplasm splits
Prophase II: nucleus disappears, chromosomes form, organelles disappear, centrioles move to opposite
ends of the cell
Metaphase II: chromosomes line up in the middle of the cell
Anaphase II: chromosomes split apart into chromatids
Telophase/Cytoplasm II: four new nuclei form, chromosomes break down into chromatin, organelles
reappear, and cytoplasm splits
Crossing over: process of exchanging of DNA segments in prophase I
Tetrads/Homologues: pairs of homologous chromosomes
Homologous: chromosomes with the same genes
Haploid: a cell with half the amount of chromosomes
Diploid: a cell with two copies of each chromosome
Karyotype: a picture of an individual’s chromosomes where you can determine sex of person and if there
are chromosomal disorders
Gametes: sex cells (egg and sperm cell)
Questions
1. How does DNA become more compact?
Chromatin wraps itself around proteins called histones in order to become more compact and fit
into the cell’s nucleus.
2. How many chromosomes are in your body?
We have 23 pairs of chromosomes in our body.
3. What is the difference between a diploid and a haploid cell?
A diploid cell has two copies of each chromosome in the cell and a haploid cell only have one copy
of each chromosome in the cell.
4. If the diploid number of a gorilla is 48, then what is the haploid number of its gametes?
48/2 = 24.
5. List the stages of the cell cycle in order?
G1  S  G2  M  C
6. Describe cytokinesis in plant cells?
In plant cells, the cell wall needs to first grow in order for there to be two new daughter cells.
During cytokinesis, the plant cell will form a cell plate in between the two daughter cells allowing
them to separate into two new cells.
7. What are the similarities and differences between mitosis and meiosis? Include phases,
movement of chromosomes, and products of each.
Stage
Mitosis
Meiosis I
Meiosis II
-Chromatin  chromosomes
-Chromatin 
-Chromosomes
chromosomes
-Nucleus disappears
remain visible
Prophase
-Nucleus
disappears
-Centrioles produce
spindle fibers and
move to opposite
poles
-Centrioles produce spindle
fibers and move to opposite
poles
-Homologus chromosomes
form into tetrads
-Nucleus
disappears
-Centrioles
produce spindle
fibers and move to
opposite poles
-Crossing over takes place
Metaphase
-Chromosomes line
up at equator of cell
-Tetrads line up at equator of
cell
Anaphase
-Chromosomes are
split into
chromatids
-Tetrads are split into
chromosomes randomly
-Nucleus reappears
Telophase/
Cytokinesis
-2 identical
daughter cells are
made
-Nucleus reappears
-2 non-identical daughter
cells are made
-Chromosomes line
up at equator of
cell
-Chromosomes are
split into
chromatids
randomly
-Nucleus reappears
-4 non-identical
daughter cells are
made
Genetics & Heredity
Vocab
 P, F1, F2 Generations: parental generation, and offspring generation
 Genotype: genetic makeup of an organism
 Phenotype: physical appearance of a trait
 Dominant: trait that can mask a recessive trait
 Recessive: trait that is not commonly seen and can be masked by a dominant trait
 Co-dominance: when the heterozygous individuals express both alleles (ex: a red flower crossed
with a white flower will make red and white speckled flowers)
 Incomplete dominance: when the heterozygous individuals expressed a mixture of both traits (ex:
a parent with curly hair and a parent with straight hair can result in offspring with wavy hair)
 Law of segregation: Law that states that alleles during gamete formation
 Pedigree: chart the shows the presence of absence of a trait according to the relationships within a
family across several generations
 Allele: one of a number of different forms of a gene
 Homozygous: having two identical alleles for a particular gene
 Heterozygous: having two different alleles for a particular gene
 Law of independent assortment: law that states that genes for different traits can segregate
independently during gamete formation
 Nondisjunction: error in meiosis in which the homologous chromosomes fail to separate properly
 Karyotype: graph of the complete diploid set of chromosomes grouped together in pairs, arranged
in order of decreasing size
 Autosome: chromosomes that are not sex chromosomes; chromosomes # 1-22
 Sex chromosome: one of the two chromosomes that determines an individual’s sex
Questions
1. Who was Mendel and what he is best known for? Mendel was an Austrian scientist that is best
known for his studies done on pea plants to explain genetics. Known as the father of genetics.
2. How was Mendel able to control fertilization with the pea plants? Mendel was able to control
fertilization with the pea plants by removing the male reproductive parts and choose with plants
were able to cross.
3. If an individual is homozygous recessive for attached earlobes and the other is heterozygous for
detached earlobes, what is the probability that their offspring will have attached earlobes? The
probability that their offspring will have attached earlobes is 50%.
4. What is the difference between cross pollination and self-pollination? In cross pollination, two
plants are crossed and with self-fertilization one plant is crossed with itself.
5. What is the genotypic ratio for a cross between two heterozygous purple pea plants? (Purple is
dominant over white) The ratio would be 1:2:1 (1 PP : 2 Pp : 1 pp)
6. What is the phenotypic ratio for a cross between a homozygous dominant individual and a
heterozygous individual? The ratio would be 1. (100% purple)
7. What information can you attain just from looking at a pedigree? What can you see from a
karyotype? A pedigree can determine what type of dominance the gene is over generations within
a family, and possibly predict future offspring. A karyotype can tell you the sex of an individual
and if there is any chromosomal disorders.
8. Why are X-linked disorders more commonly expressed in males? X-linked disorders are usually
homozugous recessive. Males only have one X chromosomes therefore they cannot mask the trait
like a female since their X chromosome is either affected or not.
9. How is it possible for one parent with A blood and the other with B blood to have a child with O
blood? If both parents are heterozygous for A and B blood, they have a 25% chance of their
offspring having O type blood.
10. What occurs in the cells during meiosis for an individual to have a child with Down syndrome?
During meiosis, the chromosomes do not split evenly and the sex cell will have an extra copy of
chromosome number 21. This occurrence is called non-disjunction.
DNA, RNA, & Protein Synthesis
Vocab
 Franklin: scientist that used X-ray diffraction to take photos of DNA
 Watson & Crick: scientists that are credited with discovering the structure of DNA
 Chargaff: scientist that discovered the arrangement of bonding nitrogenous bases (ex:
adenine=thymine, guanine=cytosine)
 Avery: scientist that worked with bacteriophage and discovered that it is the DNA that causes
infection
 DNA: nucleic acid that hold our genetic information and uses deoxyribose as the backbone
 RNA: nucleic acid that uses ribose as the sugar backbone
 mRNA: (messenger) recipe that codes for proteins
 tRNA: (transfer) brings amino acids to the ribosomes
 rRNA: (ribosomal) makes up ribosomes
 RNA Polymerase: enzyme that makes RNA from DNA template
 Transcription: synthesis of an RNA molecule from a DNA template
 Translation: process by which the sequence of bases of an mRNA is converted into the sequence of
amino acids of a protein
 Exons: expressed sequence of DNA; codes for a protein
 Introns: sequence of DNA that is not involved in coding for a protein
 Nucleotide: monomer of a DNA or RNA
 Amino acid: monomer of a protein
Questions
1. What are the three parts of a nucleotide? The three parts of a nucleotide are the sugar, phosphate
group, and nitrogenous base.
2. What is the function of DNA in organisms? The function of DNA is to store all the genetic
information for the organism.
3. List the 4 nitrogenous bases found in DNA. Adenine, guanine, thymine, cytosine
4. In DNA, which nitrogenous base bonds with adenine? Which base bonds to guanine? Adenine
bonds to thymine. Guanine bonds to cytosine.
5. In what ways does DNA differ from RNA? RNA has ribose/DNA has dexoyribose, RNA uses
uracil/DNA uses thymine, RNA is single stranded/DNA is double stranded
6. Where in the cell does transcription take place, and what is occurring during this step?
Transcriptions takes place in the nucleus and the DNA is being copied into mRNA.
7. Where in the cell does translation take place, and what is occurring during this step? Translation
takes place on a ribosome in the cytoplasm, and the mRNA is getting coded into a protein.
8. Write the mRNA sequence for the following DNA strand: TAC-AAG-CGA-ACC-TTG-ATT
AUG-UUC-GCU-UGG-AAC-UAA
9. What is the amino acid sequence for the mRNA strand you just transcribed? Met-Phe-Ala-Trp-AsnSTOP
History of Life
Vocab
 Redi: scientist that worked with flies to explain that maggots must come from pre-existing species
 Spallanzani: scientist that boiled broth with microorganisms to disprove spontaneous generation
 Pasteur: scientist that did same experiment as Spallanzani except he used a curved neck flask
 Oparin: scientist that explained what inorganic materials were in our early atmosphere
 Miller & Urey: scientists that created an experiment to explain how organic molecules were made
from inorganic matter in our early atmosphere
 Radiometric dating: method for determining the age of a sample from the amount of a radioactive
isotope
 Isotopes: a form of an element where there are more or less neutrons
 Ozone: atmospheric layer in which ozone gas is relatively concentrated; protects life on Earth
from sun’s UV rays
Questions
1. If the half-life of an isotope is 2,000 years, how much of the isotope would be left after 10,000
1
years? 32
2. How old is a specimen that contains ¼ of a radioactive isotope and its half-life is 1,600 years?
3,200 years old
3. Why was Pasteur’s experiment much more accepted by scientists during his time over
Spallanzani’s experiment? Pasteur’s experiment used a curved neck flask which allowed air to
flow into the flask, but not microorganisms. His discovery and results explained that there is no
vital force in the air to spark the production of new microorganisms. His results explained that
new microorganisms come from previous microorganisms.
4. What was the overall outcome from the Miller & Urey experiment? They were able to create amino
acids and other organic materials from inorganic gases mixed with electrical current based on the
atmosphere in the early years of our planet.
5. How do scientists believe oxygen was introduced into our atmosphere? Cyanobacteria were able
to photosynthesize and create oxygen.
6. What examples of evidence are there to back up the symbiotic theory? Chloroplasts and
mitochondria are able the size of a bacterial cell, they contain their own DNA, and replicate on
their own.
Evolution & Populations
Vocab
 Darwin: English naturalist that went to the Galapagos islands and constructed the theory of
evolution by means of natural selection based on his research
 Natural selection: process by which organisms that are most suited to their environment survive
and reproduce most successfully
 Artificial selection: process by which humans choose the organisms called selective breeding of
plants and animals to promote desirable traits in offspring
 Adaptation: heritable characteristic that increases an organism’s ability to survive and reproduce
in an environment
 Homologous: structures that are similar in species of common ancestry but have a different
function
 Analogous: body parts that share a common function but not a common structure
 Hardy-Weinberg equilibrium: principle that states that allele frequencies in a population remain
constant unless one or more factors cause those frequencies to change
 Common ancestry: explanation of how species now have many common structures derived from
each other
 Vestigial organs: structure that is inherited from ancestors but has lost much or all of its original
function
 Gene flow: when there is a change in allele frequency between populations
 Geographic isolation: form of reproductive isolation in which two populations are separated by
geographic barriers such as rivers, mountains, or bodies of water, leading to form different species
 Reproductive isolation: separation of a species or population so that they no longer interbreed and
evolve into two separate species
Questions
1. What is the driving force for evolution that Darwin highlighted in his book On the Origin of
Species? Darwin explained that natural selection is the driving force for evolution.
2. How does an animal’s fitness determine whether it will survive in an environment? An animal’s
fitness determines how well they will be able to adapt and survive in an environment and
reproduce.
3. What were Darwin’s findings with the finches of the Galapagos? Darwin found that the finches of
the Galapagos varied from island to island by their beaks. Depending on the food source on each
island, the finches adapted to their surroundings and eventually became different species.
4. What are the conditions necessary for Hardy-Weinberg equilibrium? The conditions for HardyWeinberg equilibrium are: large population, no mutations, mating is random, no
emigration/immigration, and no natural selection.
5. What are the four pieces of evidence to support the theory of evolution? DNA, biogeography,
embryology, and fossils
6. If two organisms have very similar DNA sequences, but are of different species what can be
inferred from this information? They must have shared a common ancestor.
Biotechnology (Gene Technology)
Vocab
 Restriction Enzymes: enzyme that cuts DNA at a sequence of nucleotides
 Cloning: process of creating genetically identical cells produced from a single cell
 PCR: technique used by biologists to make many copies of a particular strange of DNA
 Gel Electrophoresis: procedure used to separate and analyze DNA fragments by placing a mixture
of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel
 Recombinant DNA: DNA produced by combining DNA from different sources
 VNTR: repeats of nonsense genes found in DNA that are heritage and unique to each individual
 Carcinogen: substance that is believed to cause cancer
Questions
1. How is it possible for some plants to have a resistance to herbicides? Some organisms are
genetically modified by inserting in genes from other organisms to make them resistant to
herbicides.
2. During gel electrophoresis, how is the DNA arranged and separated by the end of the procedure?
The DNA is separated by size and charge. The smaller the DNA, the farther it gets down the gel.
3. What is the goal of the Human Genome Project? Their goal is to map out all the genes on the
chromosomes and help determine cures, treatment, and causes for specific diseases.
4. In the example of Dolly being cloned, why did the clone not live up to full life expectancy? The
clone did not live the full life expectancy because the original sheep’s DNA was already 7 years old
when inserted into the egg.
5. What are the steps to cloning? Why is it important to remove the nucleus from the egg cell? First,
extract an egg cell from a female sheep. Next, remove its nucleus and fuse with a cell of the desired
organism you want to clone (to fuse the cells you need to electric shock them). Then, allow the
cells to grow into an embryo and implant the embryo into a surrogate sheep that will bring the
clone to term. It is important to remove the nucleus from the egg cell because it contains the DNA
from a sheep that we do not want to clone.
6. What are the steps to PCR? How is this technology used in crime investigations? First, the DNA
sample, DNA polymerase, primers, and free nucleotides get added into the machine. Then, the DNA
gets heated to separate the strands. The samples are then cooled down and primers are added to
the separated strands. Next, DNA polymerase adds free nucleotides and creates new strands of
DNA. This process gets repeated until enough sample is made. This can be used by crime
investigators if there is a small sample left at a crime scene and then need more copies to analyze
who the guilty suspect is.
7. How can results from gel electrophoresis help determine family relation? By creating a bio
fingerprint from each person, you can identify patterns of VNTR sequences between samples and
determine if there is a relation.
Ecology
Vocab
 Ecosystem: all the organisms that live in a place, together with their non-living environment
 Organism: a single living thing
 Population: group of individuals of the same species that live in the same area
 Community: assemblage of different populations that live together in a defined area
 Biome: a group of ecosystems that share similar climates and typical organisms
 Biomass: total amount of living tissue within a given trophic level
 Niche: role that an organism plays in their environment
 Habitat: area where an organism lives
 Producers: first level of the trophic level (usually plants) that create energy from the sun
 Herbivores: organisms that only eat plants
 Omnivores: organisms that eat both plants and animals
 Carnivores: organisms that eat meat
 Decomposers: organism that breaks down and obtains energy from dead organic matter
 Autotroph: organisms that make their own food
 Heterotroph: organisms that need to eat food in order to get energy
 Scavengers: animal the consumes the carcasses of other animals
Questions
1. What is the difference between a food chain and a food web? A food web is a more complex system
that consists of many food chains. A food chain only follows just one path as animals find food. ex:
A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten
grass. A food web shows the many different paths plants and animals are connected.
2. Energy is transferred between trophic levels, what is the relationship between the two? The
higher you go up a trophic level the energy decreases.
3. What is the ultimate source of energy on Earth? The sun.
4. What is the difference between an organism’s habitat and niche? An organism’s habitat is where it
lives, and its niche is the role it plays in its environment.
5. How are nutrients put back into the Earth and allow the food web to be considered a cycle of life?
Decomposers are organisms at the top of every food chain that break down dead and decaying
organisms. They put nutrients back into the Earth for the producers.
6. Create a food chain starting with producers with the following organisms: rabbit, grass, bacteria,
eagle grass  rabbit  eagle  bacteria