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Biology Semester II Review


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Title: Biology Semester II Review

Biology Semester II Review
  • 2015

Mendelian Genetics chapter 11
  • 1. Use the letter T to show the following
  • Homozygous Dominant __TT___
  • Heterozygous ____Tt_
  • Homozygous Recessive __tt___
  • What would be the phenotype of each of the
    genotypes listed above?
  • Talls Tall Short

  • 2. What is a Punnett Square and how are they
    used in genetics?
  • A chart that shows all the possible outcomes of a
    mating or cross.

  • 3. Cross two heterozygous tall pea plants (T is
    the dominant allele)
  • Genotypic Ratio 1TT, 2 Tt, 1tt
  • Phenotypic Ratio 3 Tall, 1 Short

Tt tt
  • 4. Cross a heterozygous tall pea plant with a
    short one
  • Genotypic Ratio
  • 2 Tt, 2tt
  • Phenotypic Ratio
  • Half tall, half short

Tt tt
Tt tt
Genetic Engineering Chapter 13
  • 5. Analyze the DNA fingerprints below and
    identify which baby belongs to each set of
  • Smith Baby 3
  • Stevenson Baby 1
  • Jones Baby 2

  • 6. What is genetic engineering?
  • When humans purposely alter the genetic code of
    an organism
  • 7. Why is it possible to transfer DNA (genes)
    between organisms?
  • Because all organisms have DNA, the genetic code
    is universal

  • 8. How are genes arranged or organized in all
  • Genes are made of DNA which is read in groups of
    3 letters. mRNA takes this code to the cytoplasm
    where it is translated into proteins.

  • 9. Name and describe three ways genetic
    engineering is being used and applied today.
  • Making genetically modified organisms which
    include transgenic animals, transgenic plants,
    and cloning.
  • 10. Why are some people concerned or fearful of
    this technology?
  • Concerned that we cant predict how some of these
    new gene combinations might interact.

  • 10. Why are some people concerned or fearful of
    this technology?
  • People are concerned that we cant predict how
    some of these new gene combinations might

Human Genetics (Chapter 14)
  • 11. What is a Karyotype and how can it be used
    to detect chromosomal disorders in humans?
  • A karyotype is a chart of the chromosomes of an
    individual. It can be used to identify
    duplicated, and deleted chromosomes.
  • 12. Explain how these chromosomal disorders
    occur and give two specific examples.
  • Chromosomal abnormalities occur when homologous
    chromosomes fail to separate properly during
    meiosis. Examples trisomy 21 (Downs Syndrome)
    XO (Turners syndrome

  • 13. List the 4 human blood types (phenotypes)
    and all of the possible genotypes associated with
    each one. Complete the Punnett square to show the
    outcome of a cross of a person who is
    heterozygous for type A blood and a person who
    has Type AB blood.

  • Phenotypes Genotypes
  • Type A
  • Type B
  • Type AB
  • Type O

  • 14. Which chromosome carries the genes
    associated with sex linked disorders?
  • The X chromosome
  • 15. Why are males at a disadvantage in having
    an increases likelihood of inheriting these
  • Males inherit only one X chromosome. If there is
    a defective allele, they dont have another copy
    of the gene to use.

  • 16. Use the Punnett square to show the results
    of a cross between a woman who carries the gene
    for color blindness and a man with normal color

Evolution Chapter 15
  • 17. Explain the process of natural selection
    described by Charles Darwin using finches as an
    example. What is the probable ancestor to all the
    varied species of finches on the island?
  • On the islands the food is limited. Finches that
    had slight genetic differences that enabled them
    to eat other types of food survived and
    reproduced. Over time, the different types of
    finches evolved that have different shpaed beaks
    for the different food sources.

  • 18. Give an example of a homologous body
    structure and a vestigial organ.
  • Homogous structure leg of horse and fin of whale
  • 19. How do these structures provide supporting
    evidence for evolution?
  • They show evidence of a common ancestor.

  • 20. Name two other observations that also
    support the theory of evolution.
  • Fossil evidence, embryology, DNA evidence,
    Geographic distribution
  • 21. Describe the two primary sources of genetic
    variation in populations of organisms.
  • Mutation changes in DNA
  • Crossing over pieces of chromosomes are
    reshuffled during meiosis

  • 22. Why is sexual reproduction and the resulting
    genetic variation advantageous to a species as
    environmental conditions change over time?
  • It results in new combinations of genetic
    material that might provide an advantage over

  • 23. Briefly explain three different types of
    selection that act on populations of organisms
    causing traits to change over time and enable the
    population to adapt to the environment.

  • 24. Under what conditions can a population of
    organisms remain genetically stable?
  • No mutation
  • Random mating
  • No migration
  • Large population
  • No natural selection

Chapter 18 Classification
  • 25. What is binomial nomenclature? Use humans
    as the example.
  • Binomial nomenclature 2-name scientific name.
  • Example Homo genus sapien species

  • 26. How does the scientific name of an organism
    help reduce confusion among scientists?
  • A scientific name is unique. Only one organisms
    can have a particular scientific name.

  • 27. List the 8 taxonomic levels from largest to
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

  • 28. Why are dichotomous keys used in biology and
    how do they work?
  • Dichotomous keys are used to identify organisms.
    They work by asking you to always choose between
    2 characteristics. As you do this, the choices
    become more and more specific and keep dividing
    the large group into smaller and smaller groups.

Bateria and Viruses Chapter 19
  • 29. Are viruses living or nonliving? Explain
    your answer.
  • Non-living. Must have a host cell to reproduce.
  • 30. What is it necessary to produce new vaccines
    and antibiotics to combat bacterial and viral
  • Both bacteria viruses are constantly changing
    through mutations and survival of the fittest.
    Because of this, by the time we develop a
    vaccine, the virus and the bacteria have changed
    and we need to start over.

  • 31. How are the organisms in the Domains
    Eubacteria and Archaebacteria different enough
    from one another to justify classifying them into
    separate groups?
  • Eubacteria and Archaebacteria have very different
    cell walls and are found in very different
    environments. Because of this they are placed in
    different Domains.

  • 32. Which of these was probably the first life
    on earth?

  • 33. Describe two ways bacteria contribute to the
    functioning of ecosystems.
  • Bacteria are decomposers and help nutrients cycle
    through the biosphere.
  • Bacteria are nitrogen fixing. They take nitrogen
    gas from the atmosphere and change it into a form
    that plants can use.

Ecology Chapters 3-6
  • 34. Explain the relationship that exists between
    autotrophs and heterotrophs
  • Autotrophs are producers. They are able to trap
    energy from the sun into the chemical bonds of
    the sugar, glucose. Heterotrophs feed on
    autotrophs or other heterotrophs and release the
    energy from the chemical bonds for their own
    bodys uses.

  • 35. List and compare the six levels or
    organization used by ecologists to study the
  • Individual -gt population--gtcommunity--gt
  • These levels are in order from smallest to

  • 36. What is the difference between a food chain
    and a food web?
  • A food chain shows a simple feeding relationship.
  • A food web shows many feeding relationships in an
    ecosystem at one time.

37. Draw a simple example of a food chain and a
food web below, labeling each trophic level. Be
sure to include decomposers in both.
  • 38. Explain how energy and matter cycle through
    ecosystems. How are they the same, how are they
  • Energy moves one direction through the ecosystem
    with energy lost at each trophic level.
  • Matter is recycled over and over again.

39. Explain the following
  • a. What is a niche?
  • The job an organisms does in its environment.
    Example the organisms place in the food
    web--first order consumer, etc.

  • b. How do niches reduce competition in healthy
  • By having organisms occupy different niches they
    are not directly competing for the same food
    sources and other resources such as water,
    sunlight, space, etc.

  • c. What happens when populations or organisms
    compete for resources?
  • One group wins and the other loses. Usually one
    group increase in numbers over time and replaces
    the other group.

  • 40. What are three factors that can affect a
    populations size?
  • Birth rate
  • Death rate
  • Immigration/emigration

  • 41. Under ideal conditions with unlimited
    resources, what type of growth will a population
  • Exponential growth.

42. As resources become less available, what
happens to the population growth? If you were to
graph this, what would be the shape of the curve?
  • The population growth lows down and then levels
    off around the carrying capacity of that

  • 43. What is the term for the maximum number of a
    species that an ecosystem can support over time?
  • Carrying capacity
  • 44. Why is biodiversity a benefit to humans?
  • The diverse life on this planet provides us with
    food, industrial products, and medicines.

  • 45. What are some human activities that are
    causing a loss of biodiversity around the world?
  • Habitat alteration
  • Habitat fragmentation
  • Demand for wildlife products
  • Pollution
  • Introduction of alien species

  • 46. What are invasive or alien species how
    do they cause a problem in an ecosystem where
    they have been introduced?
  • Invasive or alien species are animals or plants
    introduced into new habitat. They dont have
    predators or parasites in the new environment so
    they grow rapidly. They replace native species.

  • 47. What is global warming? How is it different
    than the greenhouse effect?
  • The greenhouse effect is the normal, natural
    effect of having CO2 and H2O and methane in the
    atmosphere. These gases trap some of the suns
    energy, heating the Earth.
  • Global warming is the increase in the average
    temperature of the Earth due to the excessive
    amount of CO2 in the atmosphere. This increase
    may be due to the burning of fossil fuels.

  • 48. What is the ozone layer and why is it
  • The ozone layer is a layer of O3 in the
    atmosphere that shields the Earths surface from
    UV light. UV causes mutation in DNA

  • 49. What is the tragedy of the commons?
  • Any resource that is open to everyone will
    eventually be destroyed because everyone can use
    the resource but no one is responsible for
    preserving it.

  • 50. Why is it important to think of the Earth as
    an island?
  • Just as an island, the Earth has a limited
    resource base. We all must share it.