What is the difference between cell movements in response to outside forces and cell-generated movements (in response to specific cell activity)? (Hint: Do red blood cells move because of RBC activity? What causes cell movements associated with cytokinesis?) Using the index of your text to guide you to relevant sections in other chapters (look up entries for the various cytoskeletal proteins),
explain the different types of movements that cells generate.
What will be an ideal response?
Red blood cells and other cells in circulation move because they are suspended in a flowing fluid (blood or lymph); the axon of a nerve cell in the arm will move when the arm moves. Cell-generated movements involve the activity of actin microfilaments, intermediate filaments, microtubules, and myosin thick filaments (in muscle). The processes of chromosome alignment during mitosis/meiosis, cytoplasmic pinching during cytokinesis, beating of cilia and flagella, endocytosis and exocytosis, and muscle contraction are all examples of cell-generated
movements.
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Genetics is the study of
A. the effect of the environment on health. B. DNA. C. sperm and eggs. D. inheritance of characteristics.
Chromium is
A) a minor essential element. B) a dietary supplement with no natural role in the body. C) a major essential element. D) None of the answers are correct.
Regarding fluid movement through the capillaries,
A. blood pressure moves fluid out of the capillaries. B. osmotic pressure moves fluid into the capillaries. C. blood usually has a greater osmotic pressure than interstitial fluid. D. nine tenths of the fluid that leaves the capillary reenters the capillary. E. All of these are true statements.
Rickets is
A. a disease in adults characterized by softening of bones resulting from calcium depletion. B. a disease in children characterized by soft, bowed, and swollen bones. C. a group of genetic disorders producing very brittle bones that are easily fractured; this occurs because of insufficient collagen development. D. bone inflammation that often results from bacterial infection. E. a disease in adults, especially women, characterized by a reduced amount of bone matrix.