Botany Chapter 3: The Basics of Life and Cells PDF

Leaf No need to read Chapter three in your textbook before proceeding z Chapter Three: The Basics of Life and Cells © Bauman Books, Inc.  z Basics of Life (this material is in chap...

Leaf No need to read Chapter three in your textbook before proceeding z Chapter Three: The Basics of Life and Cells © Bauman Books, Inc.  z Basics of Life (this material is in chapter two of Stern’s Plant Biology) Life is difficult if not impossible to define However, all living things have five things in common Growth--increase in size Reproduction--increase in number Responsiveness, including adaptation--change characteristics Metabolism Cellular structure--the basic unit of all life is a cell © Bauman Books, Inc.  z Cells Two basic types of cells Eukaryotes--cells that have internal membrane- bound “organelles,” particularly the nucleus Plants Animals Fungi Prokaryotes--cells that lack internal membrane- bound “organelles;” they don’t have a nucleus Bacteria Archaea © Bauman Books, Inc.  z Plant Cells Basic unit of life Parts Cell wall--rigid but porous structure that supports and protects © Bauman Books, Inc.  z Special Features of Plant Cell Walls Multicellular plants have plasmodesmata (singular: plasmodesma)--cytoplasmic strands that go through the cell walls from one cell to another © Bauman Books, Inc.  z Special Features of Plant Cell Walls Plant cell walls are composed of a polysaccharide, cellulose, which may be reinforced with lignin or suberin, which are complex polymers of phenol Lignin Suberin Phenol © Bauman Books, Inc.  z Plant Cells Basic unit of life Parts Cell wall--rigid but porous structure that supports and protects Cytoplasmic membrane (plasmalemma, plasma membrane)-- phospholipid bilayer; “bag” that holds cellular contents Cytoplasm--contents of cell, cytosol and organelles Plastid--organelles that are centers of metabolic activity in plants Chloroplast--photosynthetic plastid Amyloplast--starch-filled plastid Chromoplast--plastid filled with carotenoid pigments Vesicle--phospholipid membrane bags Central vacuole--large vesicle in center of many plant cells Nucleus--site of DNA (genes), largest organelle Nucleolus--site within nucleus where RNA is synthesized © Bauman Books, Inc.