Biology Exam 3 questions

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Biology Exam 3 questions
2012-05-02 03:11:05
Biology Exam questions

Biology Exam 3 questions
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  1. Concentrations of soil mineral ions are greater within the root than in the soil. How do root-hair cells do this?
    active transport
  2. Why (by what mechanisms) do cells differ in their responses to hormone signals?
    Not all cells contain the receptor, Different cells may have their DNA in different chromatin configurations that allow different genes to be activated by the receptor, Different cells might contain different transcription factors that interact with the receptor to regulate transcription, and Activation of the same gene in different cells might have different effects depending on other proteins expressed in the cells
  3. Tight junctions
    Form tight seals that prevent extracellular fluids from leaking between cells
  4. Within an organism, what makes one cell type different from another?
    Each cell type expresses different genes
  5. In Drosophila oocytes, concentrations of a gene product called bicoid are high near the head and decline toward the posterior. bicoid is an example of a what?
  6. Plasmodesmata
    Permit the passage of molecules from the cytoplasm of one cell to another
  7. Stem cells
    can undergo mitosis, can differentiate into more than one type of specialized cell, vary in their potency, can sometimes only differentiate into one cell type.
  8. Plants are different from animals because plant development?
    involves organ formation in adults
  9. Sexual reproduction
    increases genetic variation
  10. In plant reproduction
    haploid individuals produce gametes via mitosis
  11. A pollen grain
    is a haploid organism, is a male gametophyte, contains 2 sperm cells, and performs double fertilization
  12. Which of the following is NOT true for both male and female mammalian gametogenesis?
    A. Gametes develop in the
    B. Primary cells (spermatocytes and oocytes) are diploid.
    C. Gametes are formed by meiosis.
    D. Germ cells multiply by mitosis.
    E.One primary cell produces four mature gametes.
    E. One primary cell produces four mature gametes
    (this multiple choice question has been scrambled)
  13. Which of the following is NOT TRUE of the placenta
    A.Functions in exchange of gases, nutrients and wastes between mother and fetus
    B. Blood of mother and fetus mix
    C.Develops from maternal and fetal tissue
    D.Many compounds can freely pass from mother to fetus
    E. Fetal portion (chorion) has chorionic villi providing a large surface area for exchange
    B. Blood of mother and fetus mix
    (this multiple choice question has been scrambled)
  14. If pregnancy occurs, then
    A. chorionic gonadotropin levels increase.
    B. A and B
    C. both progesterone and estrogen levels decrease
    D. A and C
    E. both progesterone and estrogen levels increase.
    D. A and C
    (this multiple choice question has been scrambled)
  15. What allows fetal hemoglobin to remove oxygen
    from maternal hemoglobin?
    Fetal hemoglobin has a higher affinity for oxygen than does maternal hemoglobin
  16. Essentially all exchange of gases and other
    materials between the circulatory system and tissues of the body or the outside world (e.g., in the lungs) occurs in the what?
  17. Hemoglobin is more likely to release oxygen in metabolically active tissues because why?
    CO2 is an allosteric regulator of hemoglobin
  18. Which of the following is NOT an important aspect contributing to water transport through the
    A. active transport of mineral ions from the soil into roots
    B. cohesion among H2O molecules due to hydrogen bonding
    C. osmosis due to sugar concentrations in source tissues
    D. transpirational H2O loss from leaves
    continuous tubes created by dead vessel and tracheid cells
    C. osmosis due to sugar concentrations in source tissues
    (this multiple choice question has been scrambled)
  19. Which of the following DOES NOT
    contribute to the differentiation of stem cells?
    A. cell signaling
    B. altered genetic content
    C. transcriptional hierarchy
    D. altered gene expression
    E. progressive restriction of cell fate
    B. altered genetic content
    (this multiple choice question has been scrambled)
  20. Phloem loading occurs through what?
    companion cells and plasmodesmata
  21. Alternation of generations in the plant life cycle refers to alternating between what?
    haploid and diploid
  22. In Drosophila eyes, photoreceptor cell differentiation
    occurs by
    cell signaling

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