Biology Final Exam Study Guide KEY

Final Exam Review - KEY
Genetics & Heredity
 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
 Crossing over: process in prophase I of meiosis when chromosomes exchange
genetics information
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. Why does crossing over create variation for future offspring? Crossing over allows
for genetic variation because segments of DNA are exchanged during this time and
recombinant DNA is made.
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. How does meiosis I differ from meiosis II? Meiosis I is when tetrads line up, crossing
over takes place, and tetrads split to chromosomes. Meiosis II is when chromosomes
line up and then the cell splits into 4 genetically different haploid cells.
5. What is the difference between a diploid and a haploid cell? A diploid cell has 2
copies of each chromosome, a haploid cell has half the genetic information.
6. If the diploid number of a gorilla is 48, then what is the haploid number of its
gametes? 24
7. 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)
8. What is the phenotypic ratio for a cross between a homozygous dominant
individual and a heterozygous individual? The ratio would be 1. (100% purple)
9. 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.
10. Why are X-linked disorders more commonly expressed in males? X-linked disorders
are usually homozygous 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.
11. 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.
12. 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 nondisjunction.
DNA, RNA, & Protein Synthesis
 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
 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
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
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-TTGATT
9. What is the amino acid sequence for the mRNA strand you just transcribed? MetPhe-Ala-Trp-Asn-STOP
 Darwin: English naturalist that traveled to the Galapagos and constructed the theory
of evolution by means of natural selection from his findings
 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
 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
 Hutton & Lyell: scientists that helped Darwin understand his theory of evolution
with geology
 Lamarck: scientist that came up with the theory of acquired traits and Darwin
disproved that theory
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
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 Hardy-Weinberg 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.
 Ecosystem: all the organisms that live in a place, together with their non-living
 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
 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
 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
 Mutualism: relationship when both species benefit
 Commensalism: relationship when one species benefits and the other in unaffected
 Parasitism: relationship when one species benefits and the other is harmed
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
6. Create a food chain starting with producers with the following organisms: rabbit,
grass, bacteria, eagle grass  rabbit  eagle  bacteria
 Coccus: spherical shaped prokaryote
 Bacillus: rod-shaped prokaryote
 Spirillum: spiral shaped prokaryote
 Virus: particle made of proteins, nucleic acids, and sometimes lipids that can
replicate only by infecting living cells
 Binary fission: type of asexual reproduction in which bacteria reproduce
 Peptidoglycan: protein found in bacterial cell walls
1. What are the differences between a prokaryotic cell and a eukaryotic cell?
Prokaryotic cells are smaller and do not contain a nucleus or membrane bound
organelles. Eukaryotic cells are more complex, larger, and contain a nucleus and
2. How are antibiotics used to kill bacteria in the body? Antibiotics target specific parts
of a bacteria or bacterial processes like protein synthesis. Ex: some antibiotics target
peptidoglycan which is only found in bacterial cell walls.
3. Where do phototrophic and chemoautotrophic bacteria get their energy from?
Phototrophic bacteria get energy from the sun and chemoautotrophic bacteria get
energy from chemicals.
4. What type of environments do bacteria typically grow in? Bacteria usually grow in
warm, dark, and moist areas.
5. How was the bacteria lab done in class considered to be a controlled experiment?
There was a control group (distilled) water and an experimental group (different
places swabbed) that all went through the same treatment to maintain consistency.
The experimental groups are compared to the control group for analysis.
6. Why are viruses considered to be non-living? Viruses do not carry out life process
and do not have all the characteristics of life ex: cannot reproduce, no metabolism
7. What is the difference between the lytic cycle and the lysogenic cycle? The lytic cycle
is the process when the viral DNA is using the living cell’s resources and creates new
viruses and bursts the cell. The lysogenic cycle is the process when the viral DNA is
inserted into the host’s genome and remains there with no symptoms until there is
an activation of the genes and then the viral DNA will switch to the lytic cycle.