Botany Chapter 2

Botany Chapter 2 - Chapter 2: The Nature of Life Living...

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1 Chapter 2: The Nature of Life ± Living organisms composed of cells ± Unicellular organisms ± Single cell ± Multicellular organisms ± organized to form tissues, organs, and organ systems ± Specialized molecules (usually DNA) contain genetic instructions ± Internal structures called organelles perform specific functions ± ± Exclusive to bacteria and microscopic organisms ± Simplest cell ± No nucleus or other membrane-bound organelles ± ± Contain a variety of organelles, including a nucleus, which houses DNA ± More complex ± Have a nucleus and other membrane-bound organelles Types of cells
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2 ± Biological growth ± Size of cells, the number of cells or both ± Continued growth – organism growths throughout its life (i.e., trees) ± Defined growth – has a limited growth (i.e., humans) ± Development ± All changes that take place ± Structures and body form are adapted functions ± ± Essential to nutrition, growth & repair of cells, and conversion of energy ± Regulation of metabolic processes maintains homeostasis (equilibrium) ± Respiration - Energy release. ± Photosynthesis - Energy harnessing. ± Digestion - Large insoluble food molecules converted to smaller soluble molecules. ± Assimilation - Conversion of raw materials into cell substances. ± Stimuli ± Physical or chemical changes in the internal or external environment ± Examples: ± Light ± Temperature, pressure, or sound ± The chemical composition of soil ± Callose and callus are two substances that may accumulate at wound sites in plant cells ± Movement ± Cytoplasmic streaming ± Plants respond to light, water, etc.
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3 ± Organisms can only arise from others ± Asexual ± Simple organisms ± Cells split to form 2 or more individuals ² Duplicate DNA and genetically identical ± Sexual ± Most plants and animals ± Fertilization of egg and sperm ± New organism with new genetic identity (interaction of genes/genetic variation) ± Populations evolve to better survive ± Examples ± Characteristics that enhance an organism’s ability to survive in a particular environment ± May be structural, physiological, behavioral, or a combination ± Variation among individuals ± Result of different varieties of genes that code each characteristic ± Ultimate source of variation is random mutation ± Chemical or physical changes in DNA that can be inherited ± Modifies genes Chemical and Physical Bases of Life ± ± Occupies space ± Has mass
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This note was uploaded on 04/18/2008 for the course BIO 1203 taught by Professor Tartur during the Spring '08 term at Dalton State.

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Botany Chapter 2 - Chapter 2: The Nature of Life Living...

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