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2011-09-06 07:38:11
blgy final2

blgy final2
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  1. 1. How does a biologist determine whether something is living or nonliving?
    Answer: A biologist determines whether something is living or nonliving by observing whether or not most of the life functions are performed.
  2. 2. How is nutrition in plants different from nutrition in animals?
    Answer: Plants make their own food, but animals must eat other organisms for food. Plants make food by the process of photosynthesis. Animals must hunt, capture, ingest,and digest food.
  3. 3. Place the following life functions into a logical sequence: digestion, transport, ingestion,absorption, excretion, and respiration. Explain why you selected this sequence.
    Answer: ingestion ? digestion ? transport ? absorption ? respiration ? excretion ()ingestion�food is taken into the organism. / digestion�food is broken down into small particles that can enter a cell. / transport�food is distributed to all cells of the organism. / Absorption�food molecules enter the cell. / respiration�the digested food is used for the production of energy. / excretion�the waste products of digestion (carbon dioxide and water) are removed from the organism.
  4. 4. Why must an organism possess a transport system?
    In large organisms, most cells are not in direct contact with the environment. Such organisms require a transport system so that materials such as food, water, and oxygen from the environment can be distributed to all cells.
  5. 5. Explain why homeostasis is necessary for the survival of the organism.
    The life function of regulation allows the organism to adapt to changes in its environment. An organism that cannot respond to changes in its environment might become damaged or die. Stimulus ? Homeostasis is upset. ? Response ? Homeostasis is restored. A stimulus (change in the environment of the organism) occurs. Homeostasis is upset (out of balance). The organism responds to the stimulus. Homeostasis is restored (balance).
  6. 6. Explain the following statement: �Reproduction is necessary for the survival of the species,but not for the survival of the individual.�
    Reproduction is necessary for the survival of the species. If no members of a species reproduce, the species becomes extinct. However, reproduction is not necessary for the survival of an individual member of a species. For example, if no humans reproduced, the human species would become extinct. But, an individual person does not have to reproduce to survive.
  7. 7. Which parts of the compound microscope magnify the specimen?
    Answer: The eyepiece, low-power and high-power objective lenses magnify the specimen.
  8. 8. Identify the parts of the microscope that are used for support and carrying.
    Answer: The arm and base of the microscope are used for support and carrying.
  9. 9. Where on the microscope is the specimen placed?
    Answer: The specimen is on a slide that is placed on the stage of the microscope under one of the objective lenses.
  10. 10. Which part of the microscope produces sharp focus?
    The fine adjustment knob produces sharp focus by moving the tube up and down by very small amounts.
  11. 11. How many lenses does a compound microscope use at one time?
    The compound microscope uses two lenses at a time. One is the ocular, and the other is either the low-power or high-power objective lens.
  12. 12. Why must the specimen that is placed on a slide be thin?
    The compound microscope is a light microscope, and to see a specimen, light must be able to pass through it. Therefore, the specimen must be thin.
  13. Microtome:
    This instrument is used to slice a specimen very thin so that it can be observed with a light or electron microscope.
  14. Centrifuge:
    The centrifuge is used to spin specimens at very high speeds. The heaviest and densest parts settle to the bottom, and lighter parts remain at the top. If human blood is subjected to centrifugation, plasma (the liquid part of the blood) stays at the top, and the blood cells settle to the bottom.
  15. Microdissection Tools:
    These tools are extremely small and are used with the aid of a microscope to remove or add parts to cells. Cloning, which will be discussed in a later chapter, is one use for these tools.
  16. Problem Statement:
    identify a question to be answered.
  17. Hypothesis:
    Form an educated guess that provides a possible answer to the problem statement.
  18. Experiment:
    Perform the actual procedures used to support or reject a hypothesis. The item being tested or changed is called the independent variable. The dependent variable is the change that occurs due to the procedures performed on the independent variable. The independent variable controls or determines the dependent variable. Generally, for an experiment to be considered valid, a control must be present. The control serves as a comparison point or group.
  19. Results:
    Collect and record the outcomes and information (data) obtained as a result of the experiment. A biologist determines the results by observing, measuring and weighing. The data that a biologist gathers are often presented in a table or a graph. This makes it easier to interpret the results of the experiment.
  20. Conclusions:
    Using the results of the experiment, a biologist either supports or rejects thehypothesis, thus answering the original question.
  21. Cell membrane
    Increased magnification shows that the cell membrane is composed of two layers of lipid with protein molecules suspended inside. This model of the cell membrane is called the fluid mosaic model.
  22. Endoplasmic reticulum (ER)
    The ER forms a canal-like network within the cell that functions in the transport of materials. ER with ribosomes attached is called rough ER.
  23. Ribosome
    This organelle makes proteins for the cell. Proteins are used for growth, repair, and reproduction of new cells.
  24. Mitochondrion
    This organelle is the energy factory of the cell and is associated with cellular respiration. It has an elliptical shape with outer and inner membranes. Mitochondria contain their own DNA and reproduce independently of the cell.
  25. Golgi apparatus (body)
    Flattened membranes that look like plates stacked on top of each other. The Golgi apparatus packages proteins.
  26. Lysosomes
    Small, irregularly shaped structures that have their own membrane, containing digestive enzymes for the breakdown of food.
  27. Endocytotic vesicle
    Sometimes the cell membrane can form a small pocket or pouch that can engulf particles of food (endocytosis) that are too large to pass through the membrane. This pocket is called the endocytotic vesicle.